Parallel Opportunistic Routing in Wireless Networks

We study benefits of opportunistic routing in a large wireless ad hoc network by examining how the power, delay, and total throughput scale as the number of source- destination pairs increases up to the operating maximum. Our opportunistic routing is novel in a sense that it is massively parallel, i.e., it is performed by many nodes simultaneously to maximize the opportunistic gain while controlling the inter-user interference. The scaling behavior of conventional multi-hop transmission that does not employ opportunistic routing is also examined for comparison. Our results indicate that our opportunistic routing can exhibit a net improvement in overall power--delay trade-off over the conventional routing by providing up to a logarithmic boost in the scaling law. Such a gain is possible since the receivers can tolerate more interference due to the increased received signal power provided by the multi-user diversity gain, which means that having more simultaneous transmissions is possible.Comment: 18 pages, 7 figures, Under Review for Possible Publication in IEEE Transactions on Information Theor

A Design and Development of the Learning Contents Management based on the Personalized Online Learning

Teaching-learning methods are undergoing rapid transformation in terms of new information and communication technology and in accordance with onset of the 4th Industrial Revolution. The educational environment is being transformed into various forms, with examples being found not only in the existing traditional educational environment, but also in online education and blended learning. Existing online learning (LMS, LCMS) is offered in a limited contents transmission online educational environment, and has been limited but the level of support offered to a learner’s personalized learning. This study will overview existing flexible model of contents, suggest possible problems, and attempt to solve these problems. LCMS was designed and realized based on the open source Moodle platform, offering personalized contents to learners. LCMS is composed of the following 3 functions: contents registration of metadata inputted by administrator; search functionality for personalized learner contents; and personalized contents automatically being recommended to learners. As a result of the research, we made online learning environment that can provide customized learning recommendation and self - directed learning by increasing the continuity and efficiency of learning by automatically providing customized online contents to learners. Through this study, the learning of students promises to be effectively initiated by being based on available LCMS functions related to personalized educational contents in online education

Nested Lattice Codes for Gaussian Relay Networks with Interference

In this paper, a class of relay networks is considered. We assume that, at a node, outgoing channels to its neighbors are orthogonal, while incoming signals from neighbors can interfere with each other. We are interested in the multicast capacity of these networks. As a subclass, we first focus on Gaussian relay networks with interference and find an achievable rate using a lattice coding scheme. It is shown that there is a constant gap between our achievable rate and the information theoretic cut-set bound. This is similar to the recent result by Avestimehr, Diggavi, and Tse, who showed such an approximate characterization of the capacity of general Gaussian relay networks. However, our achievability uses a structured code instead of a random one. Using the same idea used in the Gaussian case, we also consider linear finite-field symmetric networks with interference and characterize the capacity using a linear coding scheme.Comment: 23 pages, 5 figures, submitted to IEEE Transactions on Information Theor

Central vs. Peripheral Vision during a Singe-Leg Drop Jump: Implications of Dynamics and Patellofemoral Joint Stress

Landing on a single-leg without receiving direct visual information (e.g., not looking at the ground) may increase the risk of injury. We examined whether visual focus contributed to the changing lower-extremity dynamics and patellofemoral joint stress during a single-leg drop jump task. Twenty healthy volunteers visited the laboratory for three separate sessions. During each session, participants randomly performed either of two types of a single-leg drop jump task from a 30 cm high wooden box. Subsequently, participants looked at the landing spot (central vision condition) or kept their heads up (peripheral vision condition) when performing the task. Sagittal and frontal plane lower-extremity joint angles and joint moments (in the ankle, knee, and hip), including the vertical ground reaction force, and patellofemoral joint stress during the first landing phase (from initial contact to peak knee flexion) were compared. Greater ankle inversion and hip adduction were observed when landing with the peripheral vision condition. However, the magnitudes were negligeable (Cohen’s d effect siz

Comparison of Static Lower Extremity Alignment in Female Ballet Dancers and Non-ballet Dancer

PURPOSE This study aimed to: 1) compare the differences in static lower-extremity alignment (SLEA) between female ballet dancers (BD) and non-ballet dancers (NBD); 2) investigate the differences among gesture leg (GL) and supporting leg (SL) in BD and dominant leg (DL) in NBD; and 3) compare limb asymmetry between groups. METHODS Twenty-nine female BD and 20 NBD were recruited for this study. The quadriceps, tibiofemoral, rearfoot, and genu-recurvatum angles, tibial torsion and varum, and navicular drop height were measured. An independent t-test was conducted to compare SLEA and limb asymmetry between groups. One-way analysis of variance with Bonferroni post-hoc tests were performed to determine the differences among the GL, SL and DL. RESULTS BD showed lower quadriceps and rearfoot angles, less tibial varum and navicular drop, and greater tibiofemoral angle (p<.005) than NBD. BD showed less quadriceps angle asymmetry but greater tibial torsion asymmetry (p<.01) than NBD. GL and SL in BD showed differences in quadriceps, tibiofemoral, rearfoot angle, tibial torsion and navicular drop compared to NBD. CONCLUSIONS Repetitive dance movements can transfer varying forces to the GL and SL, potentially contributing to SLEA asymmetry. An intervention strategy that can reduce SLEA asymmetry in BD is needed, as is the identification of elements of ballet training that contribute to maintaining a normal SLEA

Idiopathic erythrocytosis in a patient on chronic hemodialysis

AbstractA 78-year-old man on hemodialysis presented to our hospital with erythrocytosis. He had started hemodialysis 4 years previously, with a hemoglobin level of 9.8g/dL, and was administered erythropoiesis stimulating agents and ferrous sulfate. Two years previously, his hemoglobin level increased to 14.5g/dL and the treatment for anemia was discontinued. He continued hemodialysis thrice weekly; however, the hemoglobin level had increased to 17.0g/dL at the time of presenting to our hospital. His serum erythropoietin level was 31.4mIU/mL (range, 3.7–31.5mIU/mL), carboxyhemoglobin level was 0.6% (range, 0–1.5%), and oxygen saturation in ambient air was 95.4%. The JAK2 V617F mutation was not observed and other bone marrow abnormalities were not identified. The patient was diagnosed with bladder cancer and a transurethral resection was performed. Eight months after the treatment of bladder cancer, his hemoglobin level was 15.1g/dL, and he was diagnosed with idiopathic erythrocytosis