Yonsei University

About: Yonsei University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Cancer. The organization has 50162 authors who have published 106172 publications receiving 2279044 citations. The organization is also known as: Yonsei.

Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks

Abstract: There are currently a large variety of wireless access networks, including the emerging vehicular ad hoc networks (VANETs). A large variety of applications utilizing these networks will demand features such as real-time, high-availability, and even instantaneous high-bandwidth in some cases. Therefore, it is imperative for network service providers to make the best possible use of the combined resources of available heterogeneous networks (wireless area networks (WLANs), Universal Mobile Telecommunications Systems, VANETs, Worldwide Interoperability for Microwave Access (WiMAX), etc.) for connection support. When connections need to migrate between heterogeneous networks for performance and high-availability reasons, seamless vertical handoff (VHO) is a necessary first step. In the near future, vehicular and other mobile applications will be expected to have seamless VHO between heterogeneous access networks. With regard to VHO performance, there is a critical need to develop algorithms for connection management and optimal resource allocation for seamless mobility. In this paper, we develop a VHO decision algorithm that enables a wireless access network to not only balance the overall load among all attachment points (e.g., base stations and access points) but also maximize the collective battery lifetime of mobile nodes (MNs). In addition, when ad hoc mode is applied to 3/4G wireless data networks, VANETs, and IEEE 802.11 WLANs for a more seamless integration of heterogeneous wireless networks, we devise a route-selection algorithm for forwarding data packets to the most appropriate attachment point to maximize collective battery lifetime and maintain load balancing. Results based on a detailed performance evaluation study are also presented here to demonstrate the efficacy of the proposed algorithms.

A Comparative Study of Voiding and Sexual Function after Total Mesorectal Excision with Autonomic Nerve Preservation for Rectal Cancer: Laparoscopic Versus Robotic Surgery

Abstract: To evaluate the protection of the urogenital function after robot-assisted total mesorectal excision (R-TME) for rectal cancer compared to those of laparoscopic TME (L-TME). 69 patients who underwent L-TME (n = 39) or R-TME (n = 30) were prospectively enrolled. Their urogenital function was evaluated by uroflowmetry, a standard questionnaire of the international prostate symptom score (IPSS) and the international index of erectile function (IIEF) before surgery and 1, 3, 6, and 12 months after surgery. The pre- and postoperative IPSS and IIEF scores were compared to detect functional deterioration by paired t test for each group. How postoperative IPSS and IIEF scores and uroflowmetry data deviated from the preoperative values (Δ) were statistically compared between the two groups. The IPSS score significantly increased 1 month after surgery; the recovery from decreased urinary function took 6 months for patients in the L-TME group (8.2 ± 6.3; P = 0.908) but 3 months in the R-TME group (8.36 ± 5.5; P = 0.075). The ΔIPSS scores were significantly different between the two groups at 3 months (P = 0.036). In male patients (L-TME 20, R-TME 18), the total IIEF score in R-TME and L-TME significantly decreased 1 month after surgery, L-TME gradually recovered over 12 months (46.00 ± 16.9; P = 0.269), but R-TME recovered within 6 months (44.61 ± 13.76; P = 0.067). The ΔIIEF score value was not significantly different at any time between the two groups, but in an itemized analysis of the change in erectile function and sexual desire, there were significant differences at 3 months between the two groups. R-TME for rectal cancer is associated with earlier recovery of normal voiding and sexual function compared to patients who underwent L-TME, although this result needs to be verified by larger prospective comparative studies.

Video Object Segmentation Using Space-Time Memory Networks

Abstract: We propose a novel solution for semi-supervised video object segmentation. By the nature of the problem, available cues (e.g. video frame(s) with object masks) become richer with the intermediate predictions. However, the existing methods are unable to fully exploit this rich source of information. We resolve the issue by leveraging memory networks and learn to read relevant information from all available sources. In our framework, the past frames with object masks form an external memory, and the current frame as the query is segmented using the mask information in the memory. Specifically, the query and the memory are densely matched in the feature space, covering all the space-time pixel locations in a feed-forward fashion. Contrast to the previous approaches, the abundant use of the guidance information allows us to better handle the challenges such as appearance changes and occlussions. We validate our method on the latest benchmark sets and achieved the state-of-the-art performance (overall score of 79.4 on Youtube-VOS val set, J of 88.7 and 79.2 on DAVIS 2016/2017 val set respectively) while having a fast runtime (0.16 second/frame on DAVIS 2016 val set).

Platelet microparticles induce angiogenesis in vitro.

Abstract: Platelet microparticles (PMP) are endogenous substances generated during the coagulation process in a hypercoagulable state. This study demonstrated that PMP promote the proliferation and survival, migration, and tube formation in human umbilical vein endothelial cells (HUVEC). Heat-treated PMP did not significantly decrease the angiogenic activity in HUVEC compared with that of the untreated PMP. Meanwhile when PMP were treated with activated charcoal, a procedure known to remove the lipid growth factors, the angiogenic activity was significantly reduced. These results suggest that the lipid component(s) of the PMP may be major active factor(s) and that protein component(s) may be minor contributor(s). PMP were also shown to augment endothelial progenitor cell differentiation in peripheral blood mononuclear cells. In addition, PMP-stimulated proliferation, chemotaxis and tube formation of the HUVEC was mediated via the Pertussis toxin-sensitive G protein, extracellular signal-regulated kinase and the phosphoinositide 3-kinase pathway. Herein, a new action of PMP was demonstrated to be a potent angiogenic stimulator. It is expected that in pathological states such as a growing tumour, PMP shed from the circulating platelets may reach adequate concentrations and that the elevated levels of PMP could contribute to florid formation of new blood vessels.