Moonseo Park

Opportunistic Scheduling for Three-Way Relay Systems with Physical Layer Network Coding

This paper considers a three-way wireless communication system employing physical layer network coding (PNC), where each user desires to transmit independent data to the other users via relay. However, one difficulty with this system is that the performance is limited by worst channel. To overcome this problem, we adopt a scheduling system. Since channel characteristics vary over time in wireless communications, a scheduling technique employing network coding where users are selected based on the instantaneous signal-to-noise ratio was proposed for the broadcast channel (BC) phase. In this paper, we extend the scheduling technique to the multiple access channel phase as well as the BC phase. We propose two criteria for selecting users based on the channel norm and the minimum distance criterion. Also, an efficient method to compute the minimum distance is introduced. The proposed scheduling for PNC provides a significant improvement over the conventional scheme.

Opportunistic Scheduling for Multi-User Two-Way Relay Systems with Physical Network Coding

This letter considers a multi-user wireless communication system employing physical network coding (PNC), where a pair of users communicates with each other via a relay. To attain reliable communication over time varying channels, we apply an opportunistic scheduling scheme for the PNC to both the broadcast channel phase and the multiple access channel phase. We propose two criteria for selecting users based on the channel norm and the minimum distance. Also, an efficient method to compute the minimum distance for superposed QPSK signals is introduced. Simulation results show that the proposed scheduling for PNC provides a significant improvement over conventional schemes.

Linear Precoding Design Based on the Minimum Distance for Two-Way MIMO Physical Network Coding Systems

In this paper, we propose precoding methods for multiple input multiple output physical network coding systems, which employ the modulo operation. In our work, the transmit and receive filters are determined to maximize the minimum distance on the received constellations. Especially, to address non-concavity of the given problems, we change our problem into a concave one which can be optimized by an iterative method. Also, we propose a suboptimal non-iterative scheme whose performance is very close to the optimum iterative method. In our derivations, we prove that the modulo operation achieves the optimality in terms of the minimum distance. Finally, it is confirmed from the simulation results that the proposed systems outperform conventional schemes in terms of the error performance.

Dietary Maillard reaction products and their fermented products reduce cardiovascular risk in an animal model

This study examined the effects of Maillard reaction products (MRP) and MRP fermented by lactic acid bacteria on antioxidants and their enhancement of cardiovascular health in ICR mouse and rat models. In previous in vitro studies, the selected lactic acid bacteria were shown to significantly affect the activity of MRP. The expression of genes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) related to antioxidant activity was upregulated by Maillard-reacted sodium caseinate (cMRP), and cMRP fermented by Lactobacillus fermentum H9 (F-cMRP) synergistically increased the expression of catalase and superoxide dismutase when compared with the high-cholesterol-diet group. Bleeding time, the assay for determination of antithrombotic activity, was significantly prolonged by Maillard-reacted whey protein concentration (wMRP) and wMRP fermented by Lactobacillus gasseri H10 (F-wMRP), similar to the bleeding time of the aspirin group (positive control). In addition, the acute pulmonary thromboembolism-induced mice overcame severe body paralysis or death in both the wMRP and the F-wMRP groups. In the serum-level experiment, cMRP and F-cMRP significantly reduced the serum total and low-density lipoprotein cholesterol levels and triglycerides but had only a slight effect on high-density lipoprotein cholesterol. The levels of aspartate transaminase and alanine transaminase also declined in the cMRP and F-cMRP intake groups compared with the high-cholesterol-diet group. In particular, F-cMRP showed the highest reducing effects on triglycerides, aspartate transaminase, and alanine transaminase. Moreover, the expression of cholesterol-related genes in the F-cMRP group demonstrated greater effects than for the cMRP group in the level of cholesterol 7 α-hydroxylase (CYP7A1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), and low-density lipoprotein receptors compared with the high-cholesterol-diet group. The protective role of cMRP and F-cMRP in the high-cholesterol group may have been the result of an antioxidative defense mechanism that regulated cholesterol synthesis and metabolism. Therefore, F-cMRP and cMRP have the potential to play preventive and therapeutic roles in the management of cardiovascular disease.

Precoding Designs Based on Minimum Distance for Two-Way Relaying MIMO Systems with Physical Network Coding

In this paper, we propose new precoding methods for two-way multiple input multiple output physical network coding (PNC) systems which employ the modulo operation. In our work, the transmit and receive filters are determined to maximize the minimum distance of the received constellations assuming global channel state information. The precoding operations are separately optimized for the multiple access (MA) and the broadcast stages, and the optimal precoding is obtained by applying a semidefinite relaxation method. Especially, we prove that for the system with linear detection the modulo operation for the PNC achieves optimality with the derived precoding for the MA stage in terms of the minimum distance. Also, we present a closed-form solution for the optimal filter designs for two special cases. For computing solutions, we transform our max min problem into a simple maximization problem by imposing additional constraints. Also, we propose a suboptimal non-iterative precoding scheme whose performance is within 1 dB at a bit error rate (BER) of 10-4 compared to the optimum iterative method with much reduced complexity. Finally, the simulation results show that the proposed systems achieve 2-3 dB gains at a BER of 10-4 compared to the optimal amplify-and-forward systems.

OC10.08: *The risk of preterm birth in vanishing twin: a multicentre prospective cohort study

S. Jisu1, S. Lee1, Y. Han2, M. Kim2, J. Shim3, M. Lee3, S. Oh4, J. Lee5, S. Kim6, D. Cha6, G. Cho7, H. Kwon8, B. Kim9, M. Park10, H. Cho11, H. Ko12, C. Park1, J. Park1, J. Jun1, H. Ryu2, S. Lee1 1Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Republic of Korea; 2Obstetrics and Gynecology, Cheil General Hospital and Women’s Healthcare Centre, Dankook University College of Medicine, Seoul, Republic of Korea; 3Obstetrics and Gynecology, University of Ulsan College of Medicine, Asan Medical Centre, Seoul, Republic of Korea; 4Obstetrics and Gynecology, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; 5Obstetrics and Gynecology, Institute of Women’s Life Medical Science, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Republic of Korea; 6Obstetrics and Gynecology, CHA Gangnam Medical Centre, CHA University, Seoul, Republic of Korea; 7Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Republic of Korea; 8Obstetrics and Gynecology, Konkuk University School of Medicine, Seoul, Republic of Korea; 9Obstetrics and Gynecology, Seoul Metropolitan Government Seoul National University Boramae Medical Centre, Seoul, Republic of Korea; 10Obstetrics and Gynecology, Ewha Woman’s University, Seoul, Republic of Korea; 11Obstetrics and Gynecology, CHA Bundang Medical Centre, CHA University, Sung Nam, Republic of Korea; 12Obstetrics and Gynecology, Catholic University of Korea College of Medicine, Seoul, Republic of Korea

Exact BER Analysis of Physical Layer Network Coding for Two-Way Relay Channels

Physical layer network coding (PNC) was first introduce by Zhang et al. for two-way relay channels (TWRCs). By utilizing the PNC, we can complete two-way communications within two time slots, instead of three time slots required in non-PNC systems. Recently, the upper and lower bounds for a bit error rate (BER) of PNC have been analyzed for fading channels. In this paper, we derive an exact BER of the PNC for the TWRC over fading channels. We determine decision regions based on the nearest neighbor rule and partition them into several wedge areas to apply the Craigs polar coordinate form for computing the BER. We confirm that our derived analysis accurately matches with the simulation results.

P18.02: Prenatal ultrasonographic diagnosis of congenital hereditary cataracts in a dizygotic twin

Results: Chromosomal abnormalities were found in 78 cases. In the first group the flow was abnormal in 53 cases, the overall detection rate, specificity, positive predictive value, negative predictive value and likelihood ratio for aneuploidy were 67.9%, 99.0%, 67.9%, 99% and 66.7 respectively. On basis in the ductus venosus blood flow during atrial contraction as positive marker only A-wave was negative (43 cases) the sensitivity, specificity, the positive and negative predictive values and likelihood ratio were 55.1%, 99.1%, 67.2%, 98.6%, 64.4 respectively. Conclusions: Abnormal ductus venosus blood flow is an useful marker of chromosomal anomalies in the first trimester ultrasound screening. We could improve the predictive for the detection of aneuploidies by considering absent flow during atrial contraction as a positive marker (abnormal).

P32.08: Single cervical length measurement at 36 to 38 weeks as a predictor of spontaneous onset of labor by 41 weeks

Objectives: The aim of this study was to investigate the relationship between single cervical length measurement at 36 to 38 weeks and prediction of spontaneous onset of labor by 41 weeks. Methods: We performed transvaginal ultrasound to measure single cervical length in women with singleton gestation in cephalic presentation at 36 to 38 weeks. We used a receiver operating characteristic curve (ROC) to assess the relationship between cervical length and prediction of spontaneous onset of labor by 41 weeks by SPSS 6.0. Results: For the 176 women included in the analysis, the mean cervical length (±SD) was 27.8 ± 0.96 mm. Significant probability of spontaneous labor within 41 weeks was increased when cervical length is < 20 mm. A single cervical length measurement below 30.5 mm between 36 and 38 weeks of gestation predicted spontaneous onset labor before 41 weeks gestation with a sensitivity of 61%, specificity of 84%, positive predictive value of 96% and negative predictive value of 26%. Conclusions: Single cervical length measurement at 36–38 weeks is an independent predictor of spontaneous onset of labor by 41 weeks, but with low sensitivity and negative predictive value. This information can be utilized when counseling patients regarding the management of term pregnancies.