Showing papers by "Facebook published in 2022"

Exploring Plain Vision Transformer Backbones for Object Detection

Abstract: We explore the plain, non-hierarchical Vision Transformer (ViT) as a backbone network for object detection. This design enables the original ViT architecture to be fine-tuned for object detection without needing to redesign a hierarchical backbone for pre-training. With minimal adaptations for fine-tuning, our plain-backbone detector can achieve competitive results. Surprisingly, we observe: (i) it is sufficient to build a simple feature pyramid from a single-scale feature map (without the common FPN design) and (ii) it is sufficient to use window attention (without shifting) aided with very few cross-window propagation blocks. With plain ViT backbones pre-trained as Masked Autoencoders (MAE), our detector, named ViTDet, can compete with the previous leading methods that were all based on hierarchical backbones, reaching up to 61.3 AP $$^\text {box}$$ on the COCO dataset using only ImageNet-1K pre-training. We hope our study will draw attention to research on plain-backbone detectors. Code for ViTDet is available ( https://github.com/facebookresearch/detectron2/tree/main/projects/ViTDet ).

Deep image synthesis from intuitive user input: A review and perspectives

Abstract: In many applications of computer graphics, art, and design, it is desirable for a user to provide intuitive non-image input, such as text, sketch, stroke, graph, or layout, and have a computer system automatically generate photo-realistic images according to that input. While classically, works that allow such automatic image content generation have followed a framework of image retrieval and composition, recent advances in deep generative models such as generative adversarial networks (GANs), variational autoencoders (VAEs), and flow-based methods have enabled more powerful and versatile image generation approaches. This paper reviews recent works for image synthesis given intuitive user input, covering advances in input versatility, image generation methodology, benchmark datasets, and evaluation metrics. This motivates new perspectives on input representation and interactivity, cross fertilization between major image generation paradigms, and evaluation and comparison of generation methods.

Effect of dent defects on the collapse pressure of sandwich pipes

Abstract: This paper aims to assess the effect of dent defects on the collapse pressure of sandwich pipes under external pressure. A new pipe-making process is proposed, and its ability to resist external loads is investigated. The result shows that the collapse pressure of the sandwich pipe is 76.46%–99.95% higher than that of a single-wall pipe in the same dent defect, and the buckling propagation pressure is 100% higher than the sum of the inner and outer pipes. Otherwise, the influence of the dent on the sandwich pipe is weakened. The pipe consists of two steel pipes and a polypropylene pipe bonded together by one-millimetre thick epoxy resin to form a sandwich pipe. Seven specimens with varying degrees of defects were investigated to obtain their collapse pressure, where four specimens are sandwich pipes. Additionally, a numerical model was established and validated, and systematic parametric studies were carried out to supplement the test results. The experimental and numerical results show that the collapse pressure of the sandwich pipe is significantly influenced by the dent defect. Based on the parametric study, the main parameters that affect the collapse pressure of sandwich pipes are obtained. The relationship between the collapse pressure and the geometry of the sandwich pipes was analysed. The research shows that dent defects have a significant effect on the collapse pressure of sandwich pipes and that reducing the thickness-to-ratio of the inner pipe and the friction between layers is an effective method to improve the collapse pressure of defective sandwich pipes.

Effect of dent defects on the collapse pressure of sandwich pipes

Abstract: This paper aims to assess the effect of dent defects on the collapse pressure of sandwich pipes under external pressure. A new pipe-making process is proposed, and its ability to resist external loads is investigated. The result shows that the collapse pressure of the sandwich pipe is 76.46%–99.95% higher than that of a single-wall pipe in the same dent defect, and the buckling propagation pressure is 100% higher than the sum of the inner and outer pipes. Otherwise, the influence of the dent on the sandwich pipe is weakened. The pipe consists of two steel pipes and a polypropylene pipe bonded together by one-millimetre thick epoxy resin to form a sandwich pipe. Seven specimens with varying degrees of defects were investigated to obtain their collapse pressure, where four specimens are sandwich pipes. Additionally, a numerical model was established and validated, and systematic parametric studies were carried out to supplement the test results. The experimental and numerical results show that the collapse pressure of the sandwich pipe is significantly influenced by the dent defect. Based on the parametric study, the main parameters that affect the collapse pressure of sandwich pipes are obtained. The relationship between the collapse pressure and the geometry of the sandwich pipes was analysed. The research shows that dent defects have a significant effect on the collapse pressure of sandwich pipes and that reducing the thickness-to-ratio of the inner pipe and the friction between layers is an effective method to improve the collapse pressure of defective sandwich pipes.

CFRP Strengthening and Rehabilitation of Inner Corroded Steel Pipelines under External Pressure

Abstract: The objective of this study was to investigate the performance of pipelines repaired with carbon-fibre-reinforced polymer (CFRP) under external pressure. The repaired pipeline experienced defects in terms of thinning of its local inner wall. The three-dimensional finite element method was used to analyse the collapse pressure of repaired pipes with internal corrosion defects. The traction–separation law and interlaminar damage criterion were applied to simulate the collapse process of repaired pipes. The results show that the collapse pressure of the composite-repaired pipe increased and the CFRP significantly reduced the strain in the defect region. It was observed that the ovality of the corrosion defect region was reduced and that the repair effectiveness mainly depended on the length, thickness, and interlayer cohesion.

Reverse Engineering Language Acquisition with Child-Centered Long-Form Recordings

Abstract: Language use in everyday life can be studied using lightweight, wearable recorders that collect long-form recordings—that is, audio (including speech) over whole days. The hardware and software und...

Three Things Everyone Should Know About Vision Transformers

Abstract: After their initial success in natural language processing, transformer architectures have rapidly gained traction in computer vision, providing state-of-the-art results for tasks such as image classification, detection, segmentation, and video analysis. We offer three insights based on simple and easy to implement variants of vision transformers. (1) The residual layers of vision transformers, which are usually processed sequentially, can to some extent be processed efficiently in parallel without noticeably affecting the accuracy. (2) Fine-tuning the weights of the attention layers is sufficient to adapt vision transformers to a higher resolution and to other classification tasks. This saves compute, reduces the peak memory consumption at fine-tuning time, and allows sharing the majority of weights across tasks. (3) Adding MLP-based patch pre-processing layers improves Bert-like self-supervised training based on patch masking. We evaluate the impact of these design choices using the ImageNet-1k dataset, and confirm our findings on the ImageNet-v2 test set. Transfer performance is measured across six smaller datasets.

DeiT III: Revenge of the ViT

Abstract: A Vision Transformer (ViT) is a simple neural architecture amenable to serve several computer vision tasks. It has limited built-in architectural priors, in contrast to more recent architectures that incorporate priors either about the input data or of specific tasks. Recent works show that ViTs benefit from self-supervised pre-training, in particular BerT-like pre-training like BeiT. In this paper, we revisit the supervised training of ViTs. Our procedure builds upon and simplifies a recipe introduced for training ResNet-50. It includes a new simple data-augmentation procedure with only 3 augmentations, closer to the practice in self-supervised learning. Our evaluations on Image classification (ImageNet-1k with and without pre-training on ImageNet-21k), transfer learning and semantic segmentation show that our procedure outperforms by a large margin previous fully supervised training recipes for ViT. It also reveals that the performance of our ViT trained with supervision is comparable to that of more recent architectures. Our results could serve as better baselines for recent self-supervised approaches demonstrated on ViT.

Towards compact and snapshot channeled Mueller matrix imaging

Abstract: A polarization transformation can be fully described by a 4 × 4 matrix, known as the Mueller matrix. To fully image an object's polarization response, one needs to compute the Mueller matrix at each pixel of the image. Standard divison-of-time Mueller matrix imaging, because of its sequential nature, is ill-suited to applications requiring immediate and real-time imaging and is also bulky owing to multiple moving parts. In this work, we propose a new method for compact, snapshot Mueller matrix imaging, based on structured polarization illumination, and division-of-focal plane imaging, which can, in a single-shot, fully capture the Mueller matrix information of a band-limited signal.

Reducing Conversational Agents’ Overconfidence Through Linguistic Calibration

Abstract: Abstract While improving neural dialogue agents’ factual accuracy is the object of much research, another important aspect of communication, less studied in the setting of neural dialogue, is transparency about ignorance. In this work, we analyze to what extent state-of-the-art chit-chat models are linguistically calibrated in the sense that their verbalized expression of doubt (or confidence) matches the likelihood that the model’s responses are factually incorrect (or correct). We find that these models are poorly calibrated, yet we show that likelihood of correctness can accurately be predicted. By incorporating such metacognitive features into the training of a controllable generation model, we obtain a dialogue agent with greatly improved linguistic calibration.

Parallelization of Machine Learning Algorithms Respectively on Single Machine and Spark

Abstract: With the rapid development of big data technologies, how to dig out useful information from massive data becomes an essential problem. However, using machine learning algorithms to analyze large data may be time-consuming and inefficient on the traditional single machine. To solve these problems, this paper has made some research on the parallelization of several classic machine learning algorithms respectively on the single machine and the big data platform Spark. We compare the runtime and efficiency of traditional machine learning algorithms with parallelized machine learning algorithms respectively on the single machine and Spark platform. The research results have shown significant improvement in runtime and efficiency of parallelized machine learning algorithms.

Tutorial on amortized optimization

Abstract: Optimization is a ubiquitous modeling tool and is often deployed in settings which repeatedly solve similar instances of the same problem. Amortized optimization methods use learning to predict the solutions to problems in these settings, exploiting the shared structure between similar problem instances. These methods have been crucial in variational inference and reinforcement learning and are capable of solving optimization problems many orders of magnitudes times faster than traditional optimization methods that do not use amortization. This tutorial presents an introduction to the amortized optimization foundations behind these advancements and overviews their applications in variational inference, sparse coding, gradient-based meta-learning, control, reinforcement learning, convex optimization, optimal transport, and deep equilibrium networks. The source code for this tutorial is available at https://github.com/facebookresearch/amortized-optimization-tutorial.

Commentary on 'Co-Creating Corporate Brands with Multiple Stakeholders'

Abstract: In current times when corporate brands are increasingly developing strategies with purpose and the marketing discipline as a whole is being called to explore how to create a better world and enable actions that benefit multiple stakeholders, brand co-creation naturally responds to these challenges and leads to win-win strategies for all involved. This commentary reviews the four chapters in this section that agree that co-creation is driven by the increase in technological and the increasing levels of stakeholder brand co-ownership, which implies a democratization of the value creation process. It discusses the managerial challenges that democratizing the process of value creation presents for organizations—primarily ensuring consistency while embracing diverse perspectives—and argues that the benefits of corporate brand co-creation outweigh any perceived risk.

How Local Mass Protests Influence Corporate Board Composition Change

Abstract: This paper seeks to examine how and under what conditions firms respond to large-scale street protests that do not target business. Corporate elites are more likely to notice and identify with certain social issues when high-volume street protests occur in their community. In addition, a firm’s governance structure shapes its reaction to such mass mobilizations. Using a dataset of S&P 1500 companies for the period 2017-2020, I examine the effect of Women’s March protests on firms’ appointment of new female directors. Empirical analysis demonstrates that a firm is more likely to appoint new female directors when more people participate in Women’s March activities around its headquarters. This effect is stronger when firms have more incumbent female directors and a lower level of transient ownership, and when male directors leave the boardroom. My findings offer new insights into research on how and under what conditions mass mobilization triggers responses from corporations. In addition, this research contributes to the literature on corporate governance by showing how macro-level sociopolitical contexts influence corporate governance and how existing governance structure influences firms’ responsiveness to the social movement.

Understanding Deep Contrastive Learning via Coordinate-wise Optimization

Abstract: We show that Contrastive Learning (CL) under a broad family of loss functions (including InfoNCE) has a unified formulation of coordinate-wise optimization on the network parameter $\boldsymbol{\theta}$ and pairwise importance $\alpha$, where the \emph{max player} $\boldsymbol{\theta}$ learns representation for contrastiveness, and the \emph{min player} $\alpha$ puts more weights on pairs of distinct samples that share similar representations. The resulting formulation, called $\alpha$-CL, unifies not only various existing contrastive losses, which differ by how sample-pair importance $\alpha$ is constructed, but also is able to extrapolate to give novel contrastive losses beyond popular ones, opening a new avenue of contrastive loss design. These novel losses yield comparable (or better) performance on CIFAR10, STL-10 and CIFAR-100 than classic InfoNCE. Furthermore, we also analyze the max player in detail: we prove that with fixed $\alpha$, max player is equivalent to Principal Component Analysis (PCA) for deep linear network, and almost all local minima are global and rank-1, recovering optimal PCA solutions. Finally, we extend our analysis on max player to 2-layer ReLU networks, showing that its fixed points can have higher ranks.

Elbow lateral ulnar collateral ligament reconstruction by transposition of the local extensor fascia septum: surgical technique and preliminary results

Abstract: The lateral ulnar collateral ligament (LUCL) is a primary lateral stabilizer of the elbow that originates from the isometric center of the capitulum and inserts into the supinator crest of the ulna. LUCL injury may be due to trauma, chronic strain, or iatrogenic lesion. In patients with symptomatic LUCL insufficiency and recurrent posterolateral rotatory instability, surgical reconstruction can restore elbow stability. In primary acute treatment, the injured LUCL is reattached to the lateral epicondyle with transosseous sutures and anchors placed at the isometric origin of the ligament. If the ligament quality is poor, patients with chronic elbow instability may require reconstruction with a tendon autograft or allograft. Alternatively, the LUCL can be reconstructed by transposition of the local extensor fascia septum, a local flap that exploits the common extensor fascia connected to a thin strip of extensor digitorum quinti or the extensor digitorum communis intermuscular septum. We describe a new LUCL reconstruction technique based on the transposition of the local extensor fascia septum and report the preliminary result in a series of patients aged 50 years or less. The lateral ulnar collateral ligament (LUCL) is a primary lateral stabilizer of the elbow that originates from the isometric center of the capitulum and inserts into the supinator crest of the ulna. LUCL injury may be due to trauma, chronic strain, or iatrogenic lesion. In patients with symptomatic LUCL insufficiency and recurrent posterolateral rotatory instability, surgical reconstruction can restore elbow stability. In primary acute treatment, the injured LUCL is reattached to the lateral epicondyle with transosseous sutures and anchors placed at the isometric origin of the ligament. If the ligament quality is poor, patients with chronic elbow instability may require reconstruction with a tendon autograft or allograft. Alternatively, the LUCL can be reconstructed by transposition of the local extensor fascia septum, a local flap that exploits the common extensor fascia connected to a thin strip of extensor digitorum quinti or the extensor digitorum communis intermuscular septum. We describe a new LUCL reconstruction technique based on the transposition of the local extensor fascia septum and report the preliminary result in a series of patients aged 50 years or less. The lateral ulnar collateral ligament (LUCL) is a primary lateral stabilizer of the elbow. The ulnar band of the lateral collateral ligament (LCL) complex originates from the isometric center of the capitulum and inserts into the supinator crest of the ulna. LUCL injury is usually due to trauma, chronic strain, or iatrogenic lesion. Acute severe injury of the LCL complex can lead to posterolateral rotatory instability (PLRI).14O’Driscoll S.W. Bell D.F. Morrey B.F. Posterolateral rotatory instability of the elbow.J Bone Joint Surg Am. 1991; 73A: 440-446Crossref Scopus (628) Google Scholar The lesion is commonly the result of trauma, such as a fall on an outstretched arm with the forearm supinated and the elbow slightly flexed; the humeroulnar joint rotates posterolaterally to dislocate or subluxate the elbow posteriorly. Chronic LUCL strain may arise from long-standing cubitus varus deformity resulting, for instance, from malunion of childhood supracondylar fractures, long-term crutch use,15O’Driscoll S.W. Spinner R.J. McKee M.D. Kibler W.B. Hastings H. Morrey B.F. et al.Tardy postero-lateral rotatory instability of the elbow due to cubitus varus.J Bone Joint Surg Am. 2001; 83A: 1358Crossref Scopus (160) Google Scholar or iatrogenic injury due to aggressive surgical release for lateral epicondylitis or to surgical exposure of radial head or capitulum fractures. In primary acute treatment, the injured LUCL is reattached to the lateral epicondyle with transosseous sutures and anchors placed at the isometric origin of the ligament. Patients with chronic elbow instability and poor-quality ligament tissue may require reconstruction with a tendon autograft or allograft. Transposition of the local extensor fascia septum uses a local flap of common extensor fascia connected to a thin strip of extensor digitorum quinti (EDQ) or extensor digitorum communis (EDC) intermuscular septum. We describe a new LUCL reconstruction technique involving the transposition of the local extensor fascia septum and report the preliminary result obtained in patients aged 50 years or less. Surgical reconstruction is recommended in patients with symptomatic LUCL insufficiency and recurrent PLRI to restore elbow stability. In primary acute treatment, the injured LUCL is reattached to the lateral epicondyle with transosseous sutures and anchors placed at the isometric origin of the ligament. In patients with an attenuated ligament but good-quality tissue, an advanced or imbricated suture can be performed to achieve structural stability. Patients with chronic elbow instability and inadequate ligament quality may require reconstruction with a tendon autograft/allograft. The graft selection options include an allograft (eg, plantaris tendon, semitendinosus or gracilis tendon) or an autograft (palmaris longus free strip of triceps tendon or fascia lata, gracilis tendon).3Baumfeld J.A. Van Riet R.P. Zobitz M.E. Eygendaal D. Kai-Nan A.N. Steinmann S.P. Triceps tendon properties and its potential as an autograft.J Shoulder Elbow Surg. 2010; 19: 607-609https://doi.org/10.1016/j.jse.2009.12.001Abstract Full Text Full Text PDF Scopus (19) Google Scholar,13Nestor B.J. O’Driscoll S.W. Morrey B.F. Ligamentous reconstruction for postero-lateral rotatory instability of the elbow.J Bone Joint Surg. (Am). 1992; 74: 1235-1241Crossref PubMed Scopus (244) Google Scholar,16Olsen B.S. Sojberg J.O. The treatment of recurrent postero-lateral instability of the elbow.J Bone Joint Surg Br. 2003; 85: 342-346https://doi.org/10.1302/0301-620x.85b3.13669Crossref PubMed Scopus (0) Google Scholar,18Reimann A.F. Daseler E.H. Anson B.J. Beaton L.E. – The palmaris longus muscle and tendon: A study of 1600 extremities – Anat.Rec. 1944; 89: 495-505Google Scholar We describe the transposition of the local extensor fascia septum as an LUCL reconstruction technique. This is a local flap of common extensor fascia connected to a thin strip of EDQ or EDC intermuscular septum (Fig. 1). The superficial fascia of the common extensor tendons is raised from its bed with the fascial septum, preserving the epicondyle insertion, moved laterally, and reinserted into a drill hole made in the supinator crest. The common extensor fascia is a substantial band that is easily identified and detached from the muscle fibers. In an anatomical study,4Cohen M.S. Hastings H.H. Rotatory instability of the elbow, the anatomy and role of the lateral stabilizers.J Bone Joint Surg Am. 1997; 79: 225-233Crossref PubMed Scopus (74) Google Scholar Cohen and Hastings described a distinct band of extensor carpi ulnaris (ECU) fascia, about 6 cm in length and 0.8 cm in width, running from the lateral epicondyle to the ulna. Its fibers were fused with the remaining fascia on the ECU surface, and in some cases, they merged proximally with the annular ligament and the LCL complex. Interestingly, “…a stout four-to-six millimeters intermuscular septum was noted to separate the extensor digitorum communis and extensor digiti quinti muscle compartments.”4Cohen M.S. Hastings H.H. Rotatory instability of the elbow, the anatomy and role of the lateral stabilizers.J Bone Joint Surg Am. 1997; 79: 225-233Crossref PubMed Scopus (74) Google Scholar Proximal to the radiocapitellar joint, this septal band inserts into the lateral epicondyle, where its fibers merge with the underlying LCL complex and the extensor tendon insertion. The patient lies in the supine position, and a sterile tourniquet is applied to the upper arm. The distal limited Kocher approach is performed (Fig. 2). The interval between the ECU and the anconeus is developed (Fig. 3), carefully preserving the ECU fascial band with the remaining fibers of the LCL epicondyle insertion. The fascial band usually merges with the insertions of the extensor tendons and the ECU.Figure 3The septum between the EDQ and the EDC is identified by palpation anterior to the ECU insertion, whereas the EDQ is identified by passive movement of the small finger with the wrist blocked. EDQ, extensor digitorum quinti; ECU, extensor carpi ulnaris; EDC, extensor digitorum communis.View Large Image Figure ViewerDownload Hi-res image Download (PPT) A triangular fragment of common extensor fascia (ca. 2 × 6 cm wide and 8 cm long), centered on the intermuscular septum, is marked (Fig. 4). The septum can be identified by palpation 3-4 mm medial to the ECU humeral head. The EDQ and the fascial septum are easily identified anterior to the ECU insertion by passively moving the little finger with direct palpation. The fascia can be elevated from the common extensor muscles, sparing the epicondyle insertion of the fascia and septum. The fascial flap should incorporate the superficial portion of the intermuscular septum (2-3 mm), preserving its continuity (Fig. 5, A–C) and keeping the deep portion intact. The common extensor fascial band is folded around the split septum as a rotation flap and mobilized, sparing the epicondyle insertion. Imbricated Krackow locking sutures are placed along the anterior and posterior aspects of the rotation flap, which provides a new ligament (Figs. 6 and 7).Figure 7The two long sides of the flap are folded around the split of the septum, and an imbricated Krackow locking suture is placed along the anterior and posterior aspects of the new ligament.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The interval between the EDC tendon insertion and the lateral insertions of the EDQ and the ECU is identified and split longitudinally, to expose the underlying oblique fibers of the supinator muscle (Figs. 8 and 9).Figure 9The graft is rotated posterior to the ulnar insertion under the ECU-EDQ tendon unit and above the supinator muscle. EDQ, extensor digitorum quinti; ECU, extensor carpi ulnaris.View Large Image Figure ViewerDownload Hi-res image Download (PPT) If exposure of the lateral aspect of the joint is required, as in radial head replacement, the distal deep splitting approach may be extended superiorly, as in the column approach. The insertions of the common extensor tendons (EDC, extensor carpi radialis brevis/longus) are released from the lateral column and the lateral aspect of the epicondyle, carefully preserving the insertion of the new ligament. At the end of the surgical procedure, an incision is made in the anterior capsule, and the annular ligament is divided longitudinally with stay sutures placed on both sides of the incision for anatomical repair. A plane under the ECU and EDQ tendons and above the supinator muscle fibers is carefully developed using blunt scissors so that the graft can be rotated posterior to the ulnar insertion and passed through it. To ensure alignment with the native ligament, the new ligament is fixed with a suture anchor to the isometric point identified at the center of the lateral epicondyle (Fig. 10). A groove for the rotation flap (1-1.5 × 0.5 cm) is excavated with a high-speed burr in the supinator crest, perpendicular to the intended direction of the LCL. Three holes are then drilled into its bottom on the ulnar border (Fig. 11), and the graft sutures are passed through them. The new ligament is laid in the groove, and the sutures are stretched to the correct length after repeated flexion-extension movements. Next, the sutures are tied with the forearm in full pronation and the elbow at 40° of flexion. The new ligament is sutured proximal to the remains of the native ligament, and the annular ligament incision is repaired (Fig. 12). The extensor fascia is closed, and the Kocher interval is reapproximated with absorbable sutures (Figs. 13 and 14).Figure 12The graft sutures are passed through the ulnar holes, the new ligament is introduced into the groove, and the sutures are tied with correct tension with the elbow in 40° of flexion and the forearm fully pronated. The remaining native ligament and the annular ligament are repaired in continuity with the LUCL. LUCL, lateral ulnar collateral ligament.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 13The extensor fascia is closed and the Kocher interval is reapproximated with absorbable sutures. ECU, extensor carpi ulnaris.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 14X-ray scans (case #2).View Large Image Figure ViewerDownload Hi-res image Download (PPT) •0-4 weeks: Elbow immobilization in a static posterior splint.•4-8 weeks: Hinged elbow brace enabling active and passive movement but limiting supination.•8 weeks: Active and passive movement without the brace, avoiding full supination and varus stress, and use of upper limb for normal daily activities. Data are reported as mean (± standard deviation). The normal distribution of data was tested with the Shapiro-Wilk test, and homoscedasticity was tested with the F test for homogeneity of variances. The Wilcoxon signed-rank test was used to compare variables between preoperative and postoperative assessments. A P value < .05 (2-tailed) was considered significant. Analyses were performed using the STATA software package (2009, release 11; Stata Corp, College Station, TX, USA). From 2017 to 2019, 10 consecutive patients with chronic PLRI of the elbow—7 men and 3 women—underwent LUCL reconstruction with transposition of the local extensor fascia septum at our institution. All procedures were performed by the same surgeon. Patients’ mean age at the time of surgery was 33 years (range, 25-50), and the mean interval from injury to surgery was 15 months (range, 10-20). The right elbow was involved in 9 cases (Table I). PLRI had developed after a documented traumatic dislocation of the elbow. Eight patients suffered from recurrent elbow instability (dislocation or subluxation). Two patients described snapping sensations or elbow locking symptoms. Moderate pain was reported by 7 patients, and severe pain was reported by one. Physical examination demonstrated severe limitations in daily living and sports activities in all cases. Anteroposterior dynamic examination under fluoroscopy documented varus instability in all cases. Before surgery, all patients had a positive lateral pivot shift test and a varus/valgus stability test under anesthesia. In one patient (#3), the recurrent PLRI had induced early degenerative changes to the capitulum surface; however, no additional surgical steps were performed on his elbow.Table IPreoperative clinical assessment with the Mayo Elbow Performance Score (MEPS), the QuickDash questionnaire, and the visual analog scale (VAS) for pain.Case #Gender M/FSide L/RDominant arm L/RAge (yr)Mechanism of injurySymptomsSymptom duration (mo)ROM extensionROM flexionMEPSQuickDASHVASPivot shift test under anesthesia1MRR48DislocationRecurrent subluxation1401307520.54Positive2FRR35DislocationSnapping-locking18201408011.45Positive3MRR50SubluxationRecurrent subluxation200130809.12Positive4MRR30DislocationRecurrent subluxation1201409511.40Positive5MRL33SubluxationRecurrent subluxation18101407513.63Positive6MLR25DislocationSnapping-locking16101309011.40Positive7FRR28SubluxationRecurrent subluxation1301307515.95Positive8FRR35DislocationRecurrent subluxation1501408020.55Positive9MRR25SubluxationRecurrent subluxation1001406522.77Positive10MRR27DislocationRecurrent subluxation1401408018.25PositiveROM, range of motion. Open table in a new tab ROM, range of motion. The mean follow-up was 26 months (range, 24-30). All patients were assessed for pain, range of motion, and subjective and objective stability. The Mayo Elbow Performance Score (MEPS),12Morrey B. An K. The Elbow and Its Disorders: Functional Evaluation of the Elbow.3rd ed. WB Saunders, Philadelphia, PA2000Google Scholar the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire score,6Gummesson C. Ward M. Atroshi I. The shortened disabilities of the arm, shoulder and hand questionnaire (Quick DASH): validity and reliability based on responses within the full-length DASH.BMC Musculoskelet Disord. 2006; 7: 2-3https://doi.org/10.1186/1471-2474-7-44Crossref PubMed Scopus (591) Google Scholar and the visual analog scale (VAS) score for pain8Johnson E. Visual analog scale (VAS).Am J Phys Med Rehabil. 2001; 80: 717Crossref PubMed Scopus (39) Google Scholar were calculated before surgery and at the last follow-up. At the last follow-up, 9 patients (90%) reported a completely stable elbow. The tenth (#3) described a marked improvement compared with his preoperative condition, but was unable to return to his previous level of sport activity because he felt that his elbow could not lift weights as before the trauma. The range of motion improved or was preserved in all patients (extension, from 4° ± 6.99° to 2° ± 4.22°; flexion, from 136° ± 5.16° to 135° ± 5.27°; both P ˃ .05). All clinical measures improved significantly (P < .05): the mean MEPS from 79 (79.5 ± 8.32) to 98 (98.5 ± 4.74); the mean QuickDASH score from 15.4 (15.47 ± 4.76) to 0.9 (0.91 ± 1.58), and the mean VAS score from 3.6 (3.6 ± 2.32) to 0.2 (0.2 ± 0.63) (Tables I and II).Table IIPostoperative clinical assessment with the Mayo Elbow Performance Score (MEPS), the QuickDash questionnaire, the visual analog scale (VAS) for pain and the pivot shift test.CaseFollow-up (mo)ROM extensionROM flexionMEPSQuickDASHVASX-ray assessment: ectopic bone formationX-ray assessment: degenerative joint changesPivot shift testReturn to previous sports activitiesSports activities12401301002.30Lateral epicondyleNoNegativeYesVolleyball2301014010000NoNoNegativeYesVolleyball3250130854.52NoCapitulumNegativeNoWeightlifting428014010000NoNoNegativeYesBasketball524101301002.30NoNoNegativeYesVolleyball624013010000NoNoNegativeYesFree climbing727013010000Lateral epicondyleNoNegativeYesWeightlifting824014010000NoNoNegativeYesKarate929014010000NoNoNegativeYesWeightlifting1024014010000NoNoNegativeYesWeightliftingAll patients returned to their sports. X-ray assessments: degenerative joint changes and ectopic bone formation.ROM, range of motion. Open table in a new tab All patients returned to their sports. X-ray assessments: degenerative joint changes and ectopic bone formation. ROM, range of motion. At the last clinical evaluation, 9 of 10 patients (90%) were completely without pain (Table II), whereas the lateral pivot shift test was negative for all elbows. All patients were satisfied with the outcome of their procedure, and 90% returned to their sports to the preinjury level. The X-rays showed a small ectopic bone formation without clinical relevance on the lateral epicondyle in 2 patients (#1 and 7). Early degenerative changes, detected in one patient (#3), did not progress during the study period. LUCL insufficiency is the most common cause of recurrent elbow instability. The ulnar portion of the LCL complex is attenuated, and symptoms vary from recurrent posterolateral subluxation to subtle pain and discomfort.17Regan W. Lapnes P.C. Prospective evaluation of two diagnostic apprehension signs for posterolateral instability of the elbow.J Shoulder Elbow Surg. 2006; 15: 344-346https://doi.org/10.1016/j.jse.2005.03.009Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar Patients with recurrent subluxation describe the elbow as slipping in and out of the joint and often report popping, snapping, clicking, or locking when the forearm is supinated and the elbow slightly flexed. Eight patients of our series had recurrent subluxation, and two reported snapping or locking during normal activities. Patients with chronic LUCL insufficiency experience lateral pain with a sensation of instability in certain positions when the elbow is loaded. This was the case in 80% of our patients and was the primary factor influencing the MEPS, QuickDash scores, and VAS scores. The PLRI was assessed by tests involving humeroradial joint subluxation or the typical apprehension response. Radial subluxation is easily demonstrated under anesthesia.1Arvind C.H. Hargreaves D.G. Table top relocation test: New clinical test for postero-lateral rotatory instability of the elbow.J Shoulder Elbow Surg. 2006; 15: 500-501https://doi.org/10.1016/j.jse.2005.11.014Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar,14O’Driscoll S.W. Bell D.F. Morrey B.F. Posterolateral rotatory instability of the elbow.J Bone Joint Surg Am. 1991; 73A: 440-446Crossref Scopus (628) Google Scholar,15O’Driscoll S.W. Spinner R.J. McKee M.D. Kibler W.B. Hastings H. Morrey B.F. et al.Tardy postero-lateral rotatory instability of the elbow due to cubitus varus.J Bone Joint Surg Am. 2001; 83A: 1358Crossref Scopus (160) Google Scholar,17Regan W. Lapnes P.C. Prospective evaluation of two diagnostic apprehension signs for posterolateral instability of the elbow.J Shoulder Elbow Surg. 2006; 15: 344-346https://doi.org/10.1016/j.jse.2005.03.009Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar,21Smith III, J.P. Savoie III, F.H. Field L.D. Postero-lateral rotatory instability of the elbow.Clin Orthop. 2001; 20: 47-58Scopus (43) Google Scholar Standard X-rays (anteroposterior and lateral views) are often normal. After ligament injury, small fragments of avulsed bone may be detected under the lateral epicondyle on anteroposterior radiographs. This was the case of patients #3 and 9. Posterior subluxation of the radial head with widening of the humeroulnar joint space can be detected in lateral views, whereas LUCL insufficiency is best demonstrated using radiographic or fluoroscopic stress views during the pivot shift test under anesthesia. Both conditions were detected in all our patients. Although standard magnetic resonance imaging plays a limited role, magnetic resonance arthrography may disclose LCL complex injury. Magnetic resonance imaging may depict chondral damage to the capitulum or intra-articular loose bodies, as in one of our patients (#3). Surgical management of recurrent PLRI involves direct LUCL repair or its reconstruction with a free tendon or fascia lata graft or with transposition of the local extensor fascia septum. Direct repair should be performed only in patients with good LUCL tissue quality; in the other cases, the ulnar portion of the LCL complex should be reconstructed using a free tendon or fascia graft. In patients with chronic ligament insufficiency, LUCL reconstruction with autologous graft tissue is recommended when reinsertion and plication do not appear to stabilize the humeroradial joint. An autologous free tendon graft is usually preferred, using the palmaris longus tendon (present in 85% of individuals),18Reimann A.F. Daseler E.H. Anson B.J. Beaton L.E. – The palmaris longus muscle and tendon: A study of 1600 extremities – Anat.Rec. 1944; 89: 495-505Google Scholar the plantaris tendon (found in 80% of lower limbs), a strip of triceps tendon,3Baumfeld J.A. Van Riet R.P. Zobitz M.E. Eygendaal D. Kai-Nan A.N. Steinmann S.P. Triceps tendon properties and its potential as an autograft.J Shoulder Elbow Surg. 2010; 19: 607-609https://doi.org/10.1016/j.jse.2009.12.001Abstract Full Text Full Text PDF Scopus (19) Google Scholar,16Olsen B.S. Sojberg J.O. The treatment of recurrent postero-lateral instability of the elbow.J Bone Joint Surg Br. 2003; 85: 342-346https://doi.org/10.1302/0301-620x.85b3.13669Crossref PubMed Scopus (0) Google Scholar or the gracilis or semitendinosus tendon. Different fixation techniques can be used. The traditional approaches include the figure-of-8 yoke technique,13Nestor B.J. O’Driscoll S.W. Morrey B.F. Ligamentous reconstruction for postero-lateral rotatory instability of the elbow.J Bone Joint Surg. (Am). 1992; 74: 1235-1241Crossref PubMed Scopus (244) Google Scholar the docking technique,11Metha J.A. Bain G.I. Posterolateral rotatory instability of the elbow.J Am Acad Orthop Surg. 2004; 12: 405-415https://doi.org/10.5435/00124635-200411000-00005Crossref PubMed Scopus (81) Google Scholar and the circumferential graft or box loop technique.5Finkbone P.R. O’Driscoll S.W. Box loop ligament reconstruction of the elbow for medial and lateral instability.J Shoulder Elbow Surg. 2015; 24: 647-654https://doi.org/10.1016/j.jse.2014.12.008Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar,7Hack L.M. Heinze N. Wegmann K. Lappen S. Leschinger T. Burkhart K.J. et al.The circumferential graft technique for treatment of multidirectional elbow instability: a comparative biomechanical evaluation.J Shoulder Elbow Surg. 2016; 25: 127-135https://doi.org/10.1016/j.jse.2015.07.016Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar Our ten patients with chronic LUCL insufficiency were managed with local transposition of the extensor fascia septum. The approach restored adequate lateral elbow stability and enabled return to the preinjury level of sport performance in 90% of patients. These outcomes are comparable with those obtained by other researchers with different types of autografts/allografts.2Badhrinarayanan S. Desai A. Watson J.J. White C.H.R. Phadnis J. Indications, Outcomes, and Complications of Lateral Ulnar Collateral Ligament Reconstruction of the Elbow for Chronic Posterolateral Rotatory Instability: A Systematic Review.Am J Sports Med. 2021; 49: 830-837https://doi.org/10.1177/0363546520927412Crossref PubMed Scopus (2) Google Scholar,9Lee B.P. Teo L.H. Surgical reconstruction for posterolateral rotatory instability of the elbow.J Shoulder Elbow Surg. 2003; 12: 476-479https://doi.org/10.1016/s1058-2746(03)00091-0Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar,10Lin K. Shen P. Lee C. Pan R. Lin L. Shen H. Functional outcomes of surgical reconstruction for posterolateral rotatory instability of the elbow.Injury. 2012; 43: 1657-1661https://doi.org/10.1016/j.injury.2012.04.023Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar,19Rodriguez M.J. Kusnezov N.A. Dunn J.C. Waterman B.R. Kilcoyne K.G. Functional outcomes following lateral ulnar collateral ligament reconstruction for symptomatic posterolateral rotatory instability of the elbow in an athletic population.J Shoulder Elbow Surg. 2018; 27: 112-117https://doi.org/10.1016/j.jse.2017.08.015Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar,20Sanchez-Sotelo J. Morrey B.F. O’Driscoll S.W. Ligamentous repair and reconstruction for posterolateral rotatory instability of the elbow.J Bone Joint Surg. (Br). 2005; 87: 54-61https://doi.org/10.1302/0301-620X.87B1.15096Crossref PubMed Scopus (143) Google Scholar The chief advantage of this novel technique lies in its simplicity since it uses donor tissue from the same surgical area and preserves the epicondyle insertion of the transposed local extensor fascia septum. For correct alignment with the native ligament, identification of the isometric point at the center of the lateral epicondyle allows fixation of the new ligament with a suture anchor, sparing the insertion in the transposed soft tissue. The new ligament is accommodated into a specially prepared ulnar groove, and after repeated flexion-extension movements, the sutures are tied with the forearm in full pronation and the elbow at 40° of flexion. There was no donor site morbidity, nor were there any complications related to soft tissue transposition. No adverse functional effects on hand or wrist movement were seen at the last follow-up. We attribute this outcome to the preservation of the muscle insertions and of the deep portion of the intermuscular septum. It would be interesting to compare prospectively patients treated with this technique and with other approaches using a tendon autograft/allograft. To the best of our knowledge, there are no studies describing local extensor fascia septum transposition as a reconstruction technique for chronic LUCL lesions. If ligament quality is poor, this is a useful alternative to other approaches using tendon autografts/allografts. Our experience with a mean follow-up of two years showed that the approach can stabilize the lateral compartment. Comparison of larger patient groups managed by this and other autograft/allograft reconstruction techniques is clearly needed to establish the respective medium- and long-term outcomes.

Towards Generating RESTful Full Stack Software: A Module Based Domain Driven Design Approach

Abstract: Domain-driven design (DDD) has widely been used to develop RESTful software in a range of programming language platforms. The use of code generators in these technologies helps significantly increase productivity and achieve large scale software reuse. However, there have been no work that address incremental construction of RESTful full stack software (RFS) at both the module and software levels. In this paper, we propose a generative module-based method for RFS to bridge this gap. We characterise an essential RFS and realise this in a module-based DDD software architecture, named MOSA $$ ^{R} $$ . Our method takes as input a software configuration and the required software assets and automatically generates a module-based RFS software. We present algorithms for the frontend and backend generation functions. The backend software consist of web service modules. The frontend software consists of modules that are designed with single-page views. Each view can be nested to reflect the containment tree of the module. We demonstrate by implementing the generators for two popular platforms (React and Spring Boot). The evaluation shows that the generators are able to support large software.

Computer Aided Optimization Design for New Transmission System of High-Efficiency Shearer

Abstract: Shearer is one of the core equipment of modern fully mechanized mining equipment, which is an important milestone marking the leap forward of China's mineral resources from labor-intensive to mechanized and intelligent output. At present, the cutting part of most shearers adopts the structural form of multi-stage involute spur gear linkage. The complex and large number of transmission parts have the problems of complex spatial structure and low transmission efficiency in the implementation of long-distance transmission of large torque. This paper puts forward the improved design scheme of “two-stage spur gear - two-stage bevel gear - two-stage planetary gear which greatly reduces the energy loss in the normal working process of the equipment, improves the transmission efficiency, and simplifies the spatial structure. Based on the strength theory, the weight with optimal bearing capacity and minimum volume is determined as the objective optimization function. According to the multi index constrained boundary conditions, the optimal gear train design parameters are obtained by ant colony algorithm, and the design strength meets the use requirements.

Understanding the Role of Nonlinearity in Training Dynamics of Contrastive Learning

Abstract: While the empirical success of self-supervised learning (SSL) heavily relies on the usage of deep nonlinear models, existing theoretical works on SSL understanding still focus on linear ones. In this paper, we study the role of nonlinearity in the training dynamics of contrastive learning (CL) on one and two-layer nonlinear networks with homogeneous activation $h(x) = h'(x)x$. We have two major theoretical discoveries. First, the presence of nonlinearity can lead to many local optima even in 1-layer setting, each corresponding to certain patterns from the data distribution, while with linear activation, only one major pattern can be learned. This suggests that models with lots of parameters can be regarded as a \emph{brute-force} way to find these local optima induced by nonlinearity. Second, in the 2-layer case, linear activation is proven not capable of learning specialized weights into diverse patterns, demonstrating the importance of nonlinearity. In addition, for 2-layer setting, we also discover \emph{global modulation}: those local patterns discriminative from the perspective of global-level patterns are prioritized to learn, further characterizing the learning process. Simulation verifies our theoretical findings.

Calibration of P-values for calibration and for deviation of a subpopulation from the full population

Abstract: The author's recent research papers, "Cumulative deviation of a subpopulation from the full population" and "A graphical method of cumulative differences between two subpopulations" (both published in volume 8 of Springer's open-access "Journal of Big Data" during 2021), propose graphical methods and summary statistics, without extensively calibrating formal significance tests. The summary metrics and methods can measure the calibration of probabilistic predictions and can assess differences in responses between a subpopulation and the full population while controlling for a covariate or score via conditioning on it. These recently published papers construct significance tests based on the scalar summary statistics, but only sketch how to calibrate the attained significance levels (also known as "P-values") for the tests. The present article reviews and synthesizes work spanning many decades in order to detail how to calibrate the P-values. The present paper presents computationally efficient, easily implemented numerical methods for evaluating properly calibrated P-values, together with rigorous mathematical proofs guaranteeing their accuracy, and illustrates and validates the methods with open-source software and numerical examples.