Showing papers by "University of Texas at Arlington published in 2005"
TL;DR: In this article, the authors examined how industry characteristics affect the relative importance and value of high-performance work systems and found that the impact of these human resources systems on productivity is influenced by industry capital intensity, growth, and differentiation.
Abstract: There has been growing interest in the degree to which human resource systems contribute to organizational effectiveness, yet limited research attention has been paid to the contextual conditions that moderate the efficacy of these practices. In this study, we examined how industry characteristics affect the relative importance and value of high-performance work systems. Findings indicate that the impact of these human resources systems on productivity is influenced by industry capital intensity, growth, and differentiation.
1,186 citations
TL;DR: It is shown that the constrained optimal control law has the largest region of asymptotic stability (RAS) and the result is a nearly optimal constrained state feedback controller that has been tuned a priori off-line.
1,045 citations
TL;DR: Traditional, plan-driven software development methodologies lack the flexibility to dynamically adjust the development process, so emergent organizations need information systems that constantly evolve to meet their changing requirements.
Abstract: Software development methodologies are constantly evolving due to changing technologies and new demands from users. Today's dynamic business environment has given rise to emergent organizations that continuously adapt their structures, strategies, and policies to suit the new environment [12]. Such organizations need information systems that constantly evolve to meet their changing requirements---but the traditional, plan-driven software development methodologies lack the flexibility to dynamically adjust the development process.
1,017 citations
TL;DR: It is shown that both trait-neutral and trait-based mechanisms operate simultaneously to influence diversity loss as production increases, and management that focuses on locally susceptible functional groups and generally susceptible rare species will be essential to maintain biodiversity.
Abstract: Human activities have increased N availability dramatically in terrestrial and aquatic ecosystems. Extensive research demonstrates that local plant species diversity generally declines in response to nutrient enrichment, yet the mechanisms for this decline remain unclear. Based on an analysis of >900 species responses from 34 N-fertilization experiments across nine terrestrial ecosystems in North America, we show that both trait-neutral and trait-based mechanisms operate simultaneously to influence diversity loss as production increases. Rare species were often lost because of soil fertilization, randomly with respect to traits. The risk of species loss due to fertilization ranged from >60% for the rarest species to 10% for the most abundant species. Perennials, species with N-fixing symbionts, and those of native origin also experienced increased risk of local extinction after fertilization, regardless of their initial abundance. Whereas abundance was consistently important across all systems, functional mechanisms were often system-dependent. As N availability continues to increase globally, management that focuses on locally susceptible functional groups and generally susceptible rare species will be essential to maintain biodiversity.
908 citations
28 Jan 2005
TL;DR: Smart environments represent the next evolutionary development step in building, utilities, industrial, home, shipboard, and transportation systems automation Like any sentient organism, the smart environment relies first and foremost on sensory data from the real world Sensory data comes from multiple sensors of different modalities in distributed locations as mentioned in this paper.
Abstract: Smart environments represent the next evolutionary development step in building, utilities, industrial, home, shipboard, and transportation systems automation Like any sentient organism, the smart environment relies first and foremost on sensory data from the real world Sensory data comes from multiple sensors of different modalities in distributed locations The smart environment needs information about its surroundings as well as about its internal workings; this is captured in biological systems by the distinction between exteroceptors and proprioceptors
466 citations
Journal Article•
TL;DR: Both static and proprioceptive neuromuscular facilitation stretching caused similar deficits in strength, power output, and muscle activation at both slow and fast velocities, which suggests the need for practitioners to consider a risk-to-benefit ratio when incorporating static or proprioception neuromUScularfacilitation stretching.
Abstract: Context: Stretching is commonly used as a technique for injury prevention in the clinical setting. Our findings may improve the understanding of the neuromuscular responses to stretching and help clinicians make decisions for rehabilitation progression and return to play.Objective: To examine the short-term effects of static and proprioceptive neuromuscular facilitation stretching on peak torque (PT), mean power output (MP), active range of motion (AROM), passive range of motion (PROM), electromyographic (EMG) amplitude, and mechanomyographic (MMG) amplitude of the vastus lateralis and rectus femoris muscles during voluntary maximal concentric isokinetic leg extensions at 60 and 300 degrees .s.Design: A randomized, counterbalanced, cross-sectional, repeated-measures design.Setting: A university human research laboratory.Patients or Other Participants: Ten female (age, 23 +/- 3 years) and 9 male (age, 21 +/- 3 years) apparently healthy and recreationally active volunteers.Intervention(s): Four static or proprioceptive neuromuscular facilitation stretching exercises to stretch the leg extensor muscles of the dominant limb during 2 separate, randomly ordered laboratory visits.Main Outcome Measure(s): The PT and MP were measured at 60 and 300 degrees .s, EMG and MMG signals were recorded, and AROM and PROM were measured at the knee joint before and after the stretching exercises.Results: Static and proprioceptive neuromuscular facilitation stretching reduced PT (P = .051), MP (P = .041), and EMG amplitude (P = .013) from prestretching to poststretching at 60 and 300 degrees .s (P .05).Conclusions: Both static and proprioceptive neuromuscular facilitation stretching caused similar deficits in strength, power output, and muscle activation at both slow (60 degrees .s) and fast (300 degrees .s) velocities. The effect sizes, however, corresponding to these stretching-induced changes were small, which suggests the need for practitioners to consider a risk-to-benefit ratio when incorporating static or proprioceptive neuromuscular facilitation stretching.
425 citations
TL;DR: In this article, the authors analyze fraud by senior executives in terms of its nature, scope, antecedents, and consequences, and draw on the fields of psychology, sociology, economics, and criminology to identify societal-, industry, and firm-level antecedent of management fraud and individual differences that enhance or neutralize the likelihood and degree of such fraud.
420 citations
TL;DR: This paper found that the presence of peers increases the urge to purchase, and the presence with family members decreases it, and that this difference is greater when the group (peers or family) is cohesive and when participants are susceptible to social influence.
388 citations
TL;DR: An overview of several video transcoding techniques and some of the related research issues is provided, to propose solutions to some of these research issues, and identify possible research directions.
Abstract: One of the fundamental challenges in deploying multimedia systems, such as telemedicine, education, space endeavors, marketing, crisis management, transportation, and military, is to deliver smooth and uninterruptible flow of audio-visual information, anytime and anywhere. A multimedia system may consist of various devices (PCs, laptops, PDAs, smart phones, etc.) interconnected via heterogeneous wireline and wireless networks. In such systems, multimedia content originally authored and compressed with a certain format may need bit rate adjustment and format conversion in order to allow access by receiving devices with diverse capabilities (display, memory, processing, decoder). Thus, a transcoding mechanism is required to make the content adaptive to the capabilities of diverse networks and client devices. A video transcoder can perform several additional functions. For example, if the bandwidth required for a particular video is fluctuating due to congestion or other causes, a transcoder can provide fine and dynamic adjustments in the bit rate of the video bitstream in the compressed domain without imposing additional functional requirements in the decoder. In addition, a video transcoder can change the coding parameters of the compressed video, adjust spatial and temporal resolution, and modify the video content and/or the coding standard used. This paper provides an overview of several video transcoding techniques and some of the related research issues. We introduce some of the basic concepts of video transcoding, and then review and contrast various approaches while highlighting critical research issues. We propose solutions to some of these research issues, and identify possible research directions.
374 citations
TL;DR: Both nonobese clozapine- and olanzapine's and risperidone's treatment with atypical antipsychotic agents displayed significant insulin resistance and impairment of glucose effectiveness compared with ris peridone-treated subjects.
Abstract: Background While the incidence of new-onset diabetes mellitus may be increasing in patients with schizophrenia treated with certain atypical antipsychotic agents, it remains unclear whether atypical agents are directly affecting glucose metabolism or simply increasing known risk factors for diabetes Objective To study the 2 drugs most clearly implicated (clozapine and olanzapine) and risperidone using a frequently sampled intravenous glucose tolerance test Design A cross-sectional design in stable, treated patients with schizophrenia evaluated using a frequently sampled intravenous glucose tolerance test and the Bergman minimal model analysis Setting Subjects were recruited from an urban community mental health clinic and were studied at a general clinical research center Patients Fifty subjects signed informed consent and 41 underwent the frequently sampled intravenous glucose tolerance test Thirty-six nonobese subjects with schizophrenia or schizoaffective disorder, matched by body mass index and treated with either clozapine, olanzapine, or risperidone, were included in the analysis Main Outcome Measures Fasting plasma glucose and fasting serum insulin levels, insulin sensitivity index, homeostasis model assessment of insulin resistance, and glucose effectiveness Results The mean ± SD duration of treatment with the identified atypical antipsychotic agent was 683 ± 289 months (clozapine), 295 ± 175 months (olanzapine), and 409 ± 337 (risperidone) Fasting serum insulin concentrations differed among groups (F33 = 335;P = 047) (clozapine>olanzapine>risperidone) with significant differences between clozapine and risperidone (t33 = 232;P = 03) and olanzapine and risperidone (t33 = 215;P = 04) There was a significant difference in insulin sensitivity index among groups (F33 = 1066;P olanzapine>risperidone) (clozapine vs risperidone,t33 = 294;P = 006; olanzapine vs risperidone,t33 = 242;P = 02) There was a significant difference among groups in glucose effectiveness (F30 = 418;P = 02) (clozapine Conclusions Both nonobese clozapine- and olanzapine-treated groups displayed significant insulin resistance and impairment of glucose effectiveness compared with risperidone-treated subjects Patients taking clozapine and olanzapine must be examined for insulin resistance and its consequences
336 citations
TL;DR: Video Quality Experts Group .
Abstract: PICTURE CODING AND HUMAN VISUAL SYSTEM FUNDAMENTALS Digital Picture Compression and Coding Structure . Introduction to Digital Picture Coding . Characteristics of Picture Data . Compression and Coding Techniques . Picture Quantization . Rate-Distortion Theory . Human Visual Systems . Digital Picture Coding Standards and Systems . Summary Fundamentals of Human Vision and Vision Modeling . Introduction . A Brief Overview of the Visual System . Color Vision . Luminance and the Perception of Light Intensity . Spatial Vision and Contrast Sensitivity . Temporal Vision and Motion . Visual Modeling . Conclusions Coding Artifacts and Visual Distortions . Introduction . Blocking Effect . Basis Image Effect . Blurring . Color Bleeding . Staircase Effect . Ringing . Mosaic Patterns . False Contouring . False Edges . MC Mismatch . Mosquito Effect . Stationary Area Fluctuations . Chrominance Mismatch . Video Scaling and Field Rate Conversion . Deinterlacing . Summary PICTURE QUALITY ASSESSMENT AND METRICS Video Quality Testing . Introduction . Subjective Assessment Methodologies . Selection of Test Materials . Selection of Participants-Subjects . Experimental Design . International Test Methods . Objective Assessment Methods . Summary Perceptual Video Quality Metrics-A Review . Introduction . Quality Factors . Metric Classification . Pixel-Based Metrics . The Psychophysical Approach . The Engineering Approach . Metric Comparisons . Conclusions and Perspectives Philosophy of Picture Quality Scale . Objective Picture Quality Scale for Image Coding . Application of PQS to a Variety of Electronic Images . Various Categories of Image Systems . Study at ITU . Conclusion Structural Similarity Based Image Quality Assessment . Structural Similarity Based Image Quality . The Structural SIMilarity (SSIM) Index . Image Quality Assessment Based on the SSIM Index . Discussions Vision Model Based Digital Video Impairment Metrics . Introduction . Vision Modeling for Impairment Measurement . Perceptual Blocking Distortion Metric . Perceptual Ringing Distortion Measure . Conclusion Computational Models for Just-Noticeable Difference . Introduction . JND with DCT Subbands . JND with Pixels . JND Model Evaluation . Conclusions No-Reference Quality Metric for Degraded and Enhanced Video . Introduction . State-of-the-Art for No-Reference Metrics . Quality Metric Components and Design . No-Reference Overall Quality Metric . Performance of the Quality Metric . Conclusions and Future Research Video Quality Experts Group . Formation . Goals . Phase I . Phase II . Continuing Work and Directions . Summary PERCEPTUAL CODING AND PROCESSING OF DIGITAL PICTURES HVS Based Perceptual Video Encoders . Introduction . Noise Visibility and Visual Masking . Architectures for Perceptual Based Coding . Standards-Specific Features . Salience/Maskability Pre-Processing . Application to Multi-Channel Encoding Perceptual Image Coding . Introduction . A Perceptual Distortion Metric Based Image Coder . Model Calibration . Performance Evaluation . Perceptual Lossless Coder . Summary Foveated Image and Video Coding . Foveated Human Vision and Foveated Image Processing . Foveation Methods . Scalable Foveated Image and Video Coding . Discussions Artifact Reduction by Post-Processing in Image Compression . Introduction . Image Compression and Coding Artifacts . Reduction of Blocking Artifacts . Reduction of Ringing Artifacts . Summary Reduction of Color Bleeding in DCT Block-Coded Video . Introduction . Detailed Analysis of the Color Bleeding Phenomenon . Description of the Post-Processor . Experimental Results-Concluding Remarks Error Resilience for Video Coding Service . Introduction to Error Resilient Coding Techniques . Error Resilient Coding Methods Compatible with MPEG-2 . Methods for Concealment of Cell Loss . Experimental Procedure . Experimental Results . Conclusions Critical Issues and Challenges . Picture Coding Structures . Vision Modeling Issues . Spatio-Temporal Masking in Video Coding . Picture Quality Assessment . Challenges in Perceptual Coder Design . Codec System Design Optimization . Summary Appendix: VQM Performance Metrics . Metrics Relating to Model Prediction Accuracy . Metrics Relating to Prediction Monotonicity of a Model . Metrics Relating to Prediction Consistency . MATLAB(R) Source Code . Supplementary Analyses INDEX
Posted Content•
TL;DR: In this paper, the authors explored the effects of three unique intangibility dimensions on a consumer's ability to evaluate goods and services, and the perceived risk associated with the transaction.
Abstract: Intangibility has long been studied as a unidimensional construct with the focus being placed upon the physical element. This paper explores the effects of three unique intangibility dimensions on a consumer’s ability to evaluate goods and services, and the perceived risk (PR) associated with the transaction. The authors examine these relationships in purchase environments that include both traditional bricks-and-mortar retailers and the Internet. Their investigation further incorporates prior knowledge as a moderating factor into the proposed framework. This allows for a thorough comparison of the effects and relationships that exist between intangibility and its consequences in general, evaluation difficulty (ED) and perceived risk (PR) in particular. The authors develop hypotheses pertaining to the proposed model and test them with two experiments. The empirical results are broadly supportive of the hypotheses. Theoretical and managerial implications to the services marketing literature are discussed.
TL;DR: This paper examined the relationship between top management team (TMT) characteristics (educational level, tenure, age, international experience and functional background) and firm international diversification and found that the relationships between TMT characteristics and International diversification are more dominant in better-performing than in lower-performing firms.
Abstract: Drawing on the executive demography and the upper-echelons perspectives, this paper examines the relationships between top management team (TMT) characteristics (educational level, tenure, age, international experience and functional background) and firm international diversification. The study is based on a sample of 112 relatively large, internationally diversified US-based firms in the manufacturing sector. Findings indicate that firms with higher levels of international diversification are likely to have TMTs characterized by higher educational level, shorter organizational tenures, younger executives and greater international experience. In addition, findings indicate that the relationships between TMT characteristics and international diversification are more dominant in better-performing than in lower-performing firms.
TL;DR: This article used reflectance spectroscopy to characterize the sediments in a 795-cm long core taken from the southeastern part of the lake and found that redness increases at times of increased precipitation, that is, as monsoon strength increases.
TL;DR: All of these trinuclear copper(I) pyrazolates show bright luminescence upon exposure to UV radiation, suggesting metal-centered emissions owing to intertrimer Cu...Cu interactions that are strengthened in the phosphorescent state.
Abstract: Synthetic details, solid-state structures, and photophysical properties of a group of trimeric copper(I) complexes containing pyrazolate ligands are described. The reaction of copper(I) oxide and the fluorinated pyrazoles [3-(CF3)Pz]H, [3-(CF3),5-(Me)Pz]H, and [3-(CF3),5-(Ph)Pz]H leads to the corresponding trinuclear copper(I) pyrazolates, {[3-(CF3)Pz]Cu}3, {[3-(CF3),5-(Me)Pz]Cu}3, and {[3-(CF3),5-(Ph)Pz]Cu}3, respectively, in high yield. The {[3,5-(i-Pr)2Pz]Cu}3 compound was obtained by a reaction between [Cu(CH3CN)4][BF4], [3,5-(i-Pr)2Pz]H, and NEt3. These compounds as well as {[3,5-(Me)2Pz]Cu}3 and {[3,5-(CF3)2Pz]Cu}3 adopt trimeric structures with nine-membered Cu3N6 metallacycles. There are varying degrees and types of intertrimer Cu···Cu interactions. These contacts give rise to zigzag chains in the fluorinated complexes, {[3-(CF3)Pz]Cu}3, {[3-(CF3),5-(Me)Pz]Cu}3, {[3-(CF3),5-(Ph)Pz]Cu}3, and {[3,5-(CF3)2Pz]Cu}3, whereas the nonfluorinated complexes, {[3,5-(Me)2Pz]Cu}3 and {[3,5-(i-Pr)2Pz]Cu}3 form ...
TL;DR: The decreases in PT and EMG amplitude for the unstretched limb suggested that the stretching-induced decreases may be due to a central nervous system inhibitory mechanism.
Abstract: The purpose of this study was to examine the acute effects of static stretching on peak torque (PT), the joint angle at PT, mean power output (MP), electromyographic (EMG) amplitude, and mechanomyographic (MMG) amplitude of the vastus lateralis (VL) and rectus femoris (RF) muscles during maximal, voluntary concentric isokinetic leg extensions at 60 and 240°·s-1 of the stretched and unstretched limbs. Twenty-one volunteers [mean age (SD) 21.5 (1.3) years] performed maximal, voluntary concentric isokinetic leg extensions for the dominant and non-dominant limbs at 60 and 240°·s-1. Surface EMG (μVrms) and MMG (mVrms) signals were recorded from the VL and RF muscles during the isokinetic tests. PT (Nm), the joint angle at PT, and MP (W) were calculated by a dynamometer. Following the initial isokinetic tests, the dominant leg extensors were stretched using four static stretching exercises. After the stretching, the isokinetic tests were repeated. PT decreased (P≤0.05) from pre- to post-stretching for the stretched limb at 60 and 240°·s-1 and for the unstretched limb at 60°·s-1. EMG amplitude of the VL and RF also decreased (P≤0.05) from pre- to post-stretching for the stretched and unstretched limbs. There were no stretching-induced changes (P>0.05) for the joint angle at PT, MP, or MMG amplitude. These findings indicated stretching-induced decreases in force production and muscle activation. The decreases in PT and EMG amplitude for the unstretched limb suggested that the stretching-induced decreases may be due to a central nervous system inhibitory mechanism.
TL;DR: In this paper, the authors place the research on radio frequency identification (RFID) usage in supply chains within a specific business and market context; in this case, the grocery industry.
Abstract: Purpose – To place the research on radio frequency identification (RFID) usage in supply chains within a specific business and market context; in this case, the grocery industry.Design/methodology/approach – This paper considers RFID research within the context of the grocery industry and outlines the market drivers that affect the way the grocery industry approaches RFID and also specific areas of research on RFID that should be undertaken to better provide the grocery industry with managerial insights into this technology's application.Findings – Examining market drivers that are leading to RFID implementation in the grocery industry, this paper provides a theoretical framework for future applied research on RFID implementation. Specifically, it develops a research framework that includes research using modeling techniques, RFID implementation and the impact of RFID on daily operational issues.Research limitations/implications – This paper focuses on the market drivers for RFID implementation. While it ...
TL;DR: Paulus et al. as discussed by the authors assessed the extent to which idea exposure produced cognitive stimulation and social comparison effects in group brainstorming and found that exposure to a high number of ideas and to common ideas enhanced the generation of additional ideas.
TL;DR: Remarkable luminescence properties are found for the three M3 complexes, as manifested by the appearance of multiple unstructured phosphorescence bands whose colors and lifetimes change qualitatively upon varying the coinage metal and temperature.
Abstract: This article discusses the metal effect on the supramolecular structure, photophysics, and acid-base character of trinuclear pyrazolato coinage metal complexes.
TL;DR: In this paper, a semi-empirical relation for the mass loss of cool stellar winds, which so far has frequently been described by Reimers' law, was presented, which was based solely on dimensional scaling arguments without any physical interpretation.
Abstract: We present a new semiempirical relation for the mass loss of cool stellar winds, which so far has frequently been described by "Reimers' law." Originally, this relation was based solely on dimensional scaling arguments without any physical interpretation. In our approach, the wind is assumed to result from the spillover of the extended chromosphere, possibly associated with the action of waves, especially Alfven waves, which are used as guidance in the derivation of the new formula. We obtain a relation akin to the original Reimers law, but which includes two new factors. They reflect how the chromospheric height depends on gravity and how the mechanical energy flux depends, mainly, on the effective temperature. The new relation is tested and sensitively calibrated by modeling the blue end of the horizontal branch of globular clusters. The most significant difference from mass-loss rates predicted by the Reimers relation is an increase by up to a factor of 3 for luminous late-type (super)giants, in good agreement with observations.
TL;DR: In this paper, a piezoelectric windmill with 12 bimorph actuators was demonstrated for the remote powering of sensors and communication devices, achieving a power of 10.2 mW across a load of 4.6 kΩ after rectification.
Abstract: This study demonstrates a technology, "Piezoelectric Windmill", for generating the electrical power from wind energy. The electric power-generation from wind energy is based on piezoelectric effect and utilizes the bimorph actuators. Piezoelectric Windmill consists of piezoelectric actuators arranged along the circumference of the mill in the cantilever form. Using the camshaft gear mechanism an oscillating torque is generated through the flowing wind and applied on the actuators. A working prototype was fabricated utilizing 12 bimorphs (60 ×20 ×0.5 mm3) having a preload of 23.5 gm. Under a nominal torque level corresponding to normal wind flow and oscillating frequency of 6 Hz, a power of 10.2 mW was successfully measured across a load of 4.6 kΩ after rectification. Combined with the wireless transmission, this technology provides a practical solution to the remote powering of sensors and communication devices.
TL;DR: Effective secondary prevention of work disability will require research to develop cost-effective, multipronged approaches that concurrently target both worker-related and workplace psychosocial risk factors.
Abstract: Introduction: Psychosocial factors are important contributors to work disability associated with musculoskeletal conditions. The primary objectives of this paper were 1) to describe different psychosocial interventions that have been developed to prevent prolonged work disability, and 2) to identify future research directions that might enhance the impact of programs targeting psychosocial risk factors for work disability. Methods: Selective review of scientific literature on psychosocial and behavioral interventions and work disability. Results: Most prior interventions focused on psychosocial risk factors that exist primarily within the individual (e.g., pain catastrophizing, beliefs, expectancies). Successful disability prevention will require methods to assess and target psychosocial risk factors “outside” of the individual (e.g., interpersonal conflict in the workplace, job stress, etc.) using cost-effective, multipronged approaches. Research to explore interactions among different domains of psychosocial risk factors in relation to RTW outcomes is needed. Challenges to effective secondary prevention of work disability include developing competencies to enable a range of providers to deliver interventions, standardization of psychosocial interventions, and maximizing adherence to intervention protocols. Conclusion: Effective secondary prevention of work disability will require research to develop cost-effective, multipronged approaches that concurrently target both worker-related and workplace psychosocial risk factors.
TL;DR: The results suggest that the effects of paedomorphosis on phylogenetic analyses may be complex, difficult to detect, and can lead to results that are both wrong and statistically well supported by parsimony and Bayesian analyses.
Abstract: Evolutionary developmental biology ("evo-devo") has revolutionized evolutionary biology but has had relatively little impact on systematics. We show that similar large-scale developmental changes in distantly related lineages can dramatically mislead phylogenetic analyses based on morphological data. Salamanders are important model systems in many fields of biology and are of special interest in that many species are paedomorphic and thus never complete metamorphosis. A recent study of higher-level salamander phylogeny placed most paedomorphic families in a single clade based on morphological data. Here, we use new molecular and morphological data to show that this result most likely was caused by the misleading effects of paedomorphosis. We also provide a well-supported estimate of higher-level salamander relationships based on combined molecular and morphological data. Many authors have suggested that paedomorphosis may be problematic in studies of salamander phylogeny, but this hypothesis has never been tested with a rigorous phylogenetic analysis. We find that the misleading effects of paedomorphosis on phylogenetic analysis go beyond the sharing of homoplastic larval traits by paedomorphic adults, and the problem therefore is not solved by simply excluding suspected paedomorphic characters. Instead, two additional factors are critically important in causing paedomorphic species to be phylogenetically "misplaced": (1) the absence of clade-specific synapomorphies that develop during metamorphosis in nonpaedomorphic taxa and allow their "correct" placement and (2) parallel adaptive changes associated with the aquatic habitat of the larval stage. Our results suggest that the effects of paedomorphosis on phylogenetic analyses may be complex, difficult to detect, and can lead to results that are both wrong and statistically well supported by parsimony and Bayesian analyses.
TL;DR: This article employs a contingency approach, arguing that the KM announcement would have a positive short-term impact on firm value in some conditions but not in others, and provides empirical support for the theory-based arguments, and helps develop a contingency framework of the effectiveness of KM efforts.
Abstract: The importance of knowledge management (KM) processes for organizational performance is now well recognized. Seeking to better understand the short-term impact of KM on firm value, this article focuses on public announcements of information technology (IT)-based KM efforts, and uses cumulative abnormal return (CAR) associated with an announcement as the dependent variable. This article employs a contingency approach, arguing that the KM announcement would have a positive short-term impact on firm value in some conditions but not in others. Thus, it pursues the following research question: What are the effects of contextual factors on the CAR associated with the announcement of an IT-based KM effort? Specific hypotheses are proposed based on information-processing theory, organizational learning theory, the knowledge-based theory of the firm, and the theory of knowledge creation. These hypotheses link CARs to alignment between industry innovativeness and the KM process, alignment between firm efficiency and the KM process, firm-specific instability, and firm diversification. The empirical study utilizes secondary data on 89 KM announcements from 1995 to 2002. The results largely support the hypotheses. Overall, this article provides empirical support for the theory-based arguments, and helps develop a contingency framework of the effectiveness of KM efforts.
TL;DR: In this article, the authors proposed a new technique for generating smoothed APW paths based on the latest version (4.5a) of the Global Paleomagnetic Database (GPMDB), a revised global plate tectonic model since the Early Jurassic, and a smoothing technique including pre-selection of palaeopoles.
Abstract: SUMMARY Synthetic apparent polar wander (APW) paths for North America, South America, Eurasia, India, Central Africa, Australia and Antarctica for the last 200 Myr are proposed. Computation of these APW paths is based upon the latest version (4.5a) of the Global Paleomagnetic Database (GPMDB), a revised global plate tectonic model since the Early Jurassic, and a new technique for generating smoothed APW paths. The smoothing technique includes the following steps: (1) pre-selection of palaeopoles, including pre-filtering parameters (number of sites, number of samples per site, 95 per cent confidence circle about mean direction, cleaning procedure, and time uncertainty); (2) generation of palaeolatitude and declination plots for a reference site on each continent that combines palaeopoles via a global plate tectonic circuit; (3) independent spline regression analyses of the palaeolatitude and declination plots; (4) removal of palaeolatitude or declination data that deviate by more than 10 ◦ from the regression curves (post-filtering process); (5) generation of synthetic APW paths from the resulting palaeolatitude and declination plots. These synthetic APW paths are then rotated into African coordinates to determine the best-fit APW path and a global palaeomagnetic reference frame. Four representative plate tectonic reconstructions and global plate velocity fields are presented for the three time intervals that correspond to globally synchronous changes in plate motion.
TL;DR: In this article, a simple 0.5 power relationship between the splitting tensile strength and the compressive strength of GFRC and PFRC has been derived for estimating the tensile strengths of concrete.
02 Sep 2005
TL;DR: A novel group-based key pre-distribution framework is developed, which does not require the knowledge of sensors' expected locations and greatly simplifies the deployment of sensor networks.
Abstract: Many key pre-distribution techniques have been developed recently to establish pairwise keys for wireless sensor networks. To further improve these schemes, researchers have proposed to take advantage of sensors' expected locations to help pre-distributing keying materials. However, it is usually very difficult, and sometimes impossible, to guarantee the knowledge of sensors' expected locations. In order to remove the dependency on expected locations, this paper proposes a practical deployment model, where sensor nodes are deployed in groups, and the nodes in the same group are close to each other after the deployment. Based on this model, the paper develops a novel group-based key pre-distribution framework, which can be combined with any of existing key pre-distribution techniques. A distinguishing property of this framework is that it does not require the knowledge of sensors' expected locations and greatly simplifies the deployment of sensor networks. The analysis also shows that the framework can substantially improve the security as well as the performance of existing key pre-distribution techniques.
TL;DR: Two key predistribution schemes are developed, a closest pairwise keys scheme and a closest polynomials scheme, and the analysis shows that these schemes can achieve better performance if the expected location information is available and that the smaller the deployment error is, the better performance they can achieve.
Abstract: Pairwise key establishment is a fundamental security service for sensor networks. However, establishing pairwise keys in sensor networks is a challenging problem, particularly due to the resource constraints on sensor nodes and the threat of node compromises. This article proposes to use both predeployment and postdeployment knowledge to improve pairwise key predistribution in static sensor networks. By exploiting the predeployment knowledge, this article first develops two key predistribution schemes, a closest pairwise keys scheme and a closest polynomials scheme. The analysis shows that these schemes can achieve better performance if the expected location information is available and that the smaller the deployment error is, the better performance they can achieve. The article then investigates how to use postdeployment knowledge to improve pairwise key predistribution in static sensor networks. The idea is to load an excessive amount of predistributed keys on sensor nodes, prioritize these keys based on sensors' actual locations discovered after deployment, and discard low-priority keys to thwart node compromise attacks. This approach is then used to improve the random subset assignment scheme proposed recently to demonstrate its practicality and effectiveness. The analysis indicates that the postdeployment knowledge can also greatly improve the performance and security of key predistribution.
TL;DR: A typical pattern for a new industry is to have an initial phase where a small number of firms each earn significant profits, followed by a phase in which rapid entry of new firms leads to increased competition and dissipation of some of those profits, often accompanied by a shakeout whereby only a few large firms remain this article.
Abstract: Both the economics literature and the business press suggest that a typical pattern for a “new” industry [or what Jovanovic and MacDonald (1994) call an invention ]i s to have an initial phase in which a small number of firms each earn significant profits, followed by a phase in which rapid entry of new firms leads to increased competition and dissipation of some of those profits, often accompanied by a shakeout, whereby only a few large firms remain (especially if subsequent innovations increase the optimal scale). Although this pattern seems to characterize many industries, the length of time during which early movers retain their profits, how prices adjust during the entry process, and the
TL;DR: Understanding and preventing delayed RTW will require application of new concepts and study designs, better measures of determinants and outcomes, and more translational research.
Abstract: Background: Despite considerable multidisciplinary research on return to work (RTW), there has been only modest progress in implementation of study results, and little change in overall rates of work disability in developed countries. Methods: Thirty RTW researchers, representing over 20 institutions, assembled to review the current state of the art in RTW research, to identify promising areas for further development, and to provide direction for future investigations. Results and Conclusion: Six major themes were selected as priority areas: early risk prediction; psychosocial, behavioral and cognitive interventions; physical treatments; the challenge of implementing evidence in the workplace context; effective methods to engage multiple stakeholders; and identification of outcomes that are relevant to both RTW stakeholders and different phases of the RTW process. Understanding and preventing delayed RTW will require application of new concepts and study designs, better measures of determinants and outcomes, and more translational research. Greater stakeholder involvement and commitment, and methods to address the unique challenges of each situation are required.