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Search Results: 1 - 10 of 11223 matches for " Seung-Jong Park "
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Energy Efficient Correlated Data Aggregation for Wireless Sensor Networks
Seung-Jong Park,Raghupathy Sivakumar
International Journal of Distributed Sensor Networks , 2008, DOI: 10.1080/15501320701774592
Abstract: Data aggregations from Sensors to a sink in wireless sensor networks (WSNs) are typically characterized by correlation along the spatial, semantic, and temporal dimensions. Exploiting such correlation when performing data aggregation can result in considerable improvements in the bandwidth and energy performance of WSNs. For the sensors-to-sink data delivery, we first explore two theoretical solutions: the shortest path tree (SPT) and the minimum spanning tree (MST) approaches. To approximate the optimal solution (MST) in case of perfect correlation among data, we propose a new aggregation which combines the minimum dominating set (MDS) with the shortest path tree (SPT) in order to aggregate correlated data. To reduce the redundancy among correlated data and simplify the synchronization among transmission, the proposed aggregation takes two stages: local aggregation among sensors around a node in the MDS and global aggregation among sensors in the MDS. Finally, using discrete event simulations, we show that the proposed aggregation outperforms the SPT and closely approximates the centralized optimal solution, the MST, with less amount of overhead and in a decentralized fashion.
Impact of Loss Synchronization on Reliable High Speed Networks: A Model Based Simulation
Suman Kumar,Lin Xue,Seung-Jong Park
Journal of Computer Networks and Communications , 2014, DOI: 10.1155/2014/795489
Abstract: Contemporary nature of network evolution demands for simulation models which are flexible, scalable, and easily implementable. In this paper, we propose a fluid based model for performance analysis of reliable high speed networks. In particular, this paper aims to study the dynamic relationship between congestion control algorithms and queue management schemes, in order to develop a better understanding of the causal linkages between the two. We propose a loss synchronization module which is user configurable. We validate our model through simulations under controlled settings. Also, we present a performance analysis to provide insights into two important issues concerning 10?Gbps high speed networks: (i) impact of bottleneck buffer size on the performance of 10?Gbps high speed network and (ii) impact of level of loss synchronization on link utilization-fairness tradeoffs. The practical impact of the proposed work is to provide design guidelines along with a powerful simulation tool to protocol designers and network developers. 1. Introduction As one of the basic characteristics of computer networks, a dynamical system, TCP flow synchronization/desynchronization, is very important and interesting. In fact, level of loss synchronization is proven to be the major impact factor for the performance of computer networks. Modeling the loss synchronization has been a challenging task for network researchers especially for high speed networks. A few studies have concentrated on loss synchronization studies on high speed networks such as [1–3]. The work in [1] presents an analytical model using M/M/1/K queuing model approximations that is only valid for HighSpeed TCP (HSTCP) [4]. The work in [2, 3] presents synchronization statistics in a high speed network environment via simulation. However, both [2, 3] do not answer the question: how does loss synchronization level affect the performance of high speed TCP variants? Or how does loss synchronization affect the design of high speed networks? Also, these works do not address 10?Gbps high speed networks. Hardware technologies and network applications have been bringing rapid changes in protocols at transport layer as well as at network layer. At the same time, network community must understand the behavior of these protocols in order to support research and development of next generation networks. This understanding is especially important to improve the robustness of protocol implementations and network applications. In general, networking protocol developers have to repeat a cycle consisting of two steps: they
Stable 2D Feature Tracking for Long Video Sequences
Jong-Seung Park,Jong-Hyun Yoon,Chungkyue Kim
International Journal of Signal Processing, Image Processing and Pattern Recognition , 2008,
Abstract: In this paper, we propose a 2D feature tracking method that is stable to long video sequences. To improve the stability of long tracking, we use trajectory information about 2D features. We predict the expected feature states and compute a rough estimate of the feature location on the current image frame using the history of previous feature states up to the current frame. A search window is positioned at the estimated location and similarity measures are computed within the search window. Once the feature position is determined from the similarity measures, the current feature states are appended to the history bu er. The outlier rejection stage is also introduced to reduce false matches. Experimental results from real video sequences showed that the proposed method stably tracks point features for long frame sequences.
The Relationship between Thyroid Hormone Levels and Corrected QT Interval and QT Dispersion in Non-Diabetic Hemodialysis Patients  [PDF]
Heo-Yeong Kim, Ji Soo Kim, Seung Eun Suh, Yu Kyung Hyun, Kyeong Mi Park, Hyung-Jong Kim
Open Journal of Nephrology (OJNeph) , 2014, DOI: 10.4236/ojneph.2014.41003

Background: Cardiovascular disease and sudden cardiac death are common in hemodialysis patients. These cardiac complications are often associated with prolonged QTc interval (QTc) and QTc dispersion (QTcd). Subclinical hypothyroidism (SH) can alter autonomic modulation of heart rate and cause increased inhomogeneity of ventricular recovery time. We aimed to evaluate the relationship between thyroid hormone levels and QTc and QTcd in non-diabetic hemodialysis patients. Methods: We enrolled 29 non-diabetic hemodialysis patients without thyroid disease. After each hemodialysis session, a 12-lead ECG was recorded. Before each hemodialysis session, routine laboratory tests and measurement of thyroid hormone levels were performed. Patients were divided into 2 groups according to QTc (group 1 QTc < 430 ms, group 2 QTc ≥ 430 ms). We examined the relationship between QTc or QTcd and thyroid hormone in the respective groups and then compared the results from the 2 groups. Results: The mean age was 54.06 ± 14.72 years and the means of QTc and QTcd were 433.82 ± 22.03 ms, 59.10 ± 28.29 ms, respectively. Homocysteine levels were significant higher in group 2 than group 1 (p < 0.05) and QTcd was comparable between groups. In group 1, QTc and QTcd were not significant correlated with TSH, T3, fT4 and biochemical parameters. In group 2, QTc was significant positively correlated with TSH (p < 0.05) and QTcd was

High-risk Human Papillomavirus Infection in Low Risk Women: Incidence, Patient Characteristics, and Clinical Meaning for Cervical Cancer
Sung Jong Lee, Seung Geun Yeo, Dong Choon Park
International Journal of Medical Sciences , 2012,
Abstract: Objective: To investigate the incidence of high-risk human papillomavirus (HPV) infection and its clinical meaning. Methods: Total 28,339 women attending our hospital for routine gynecologic care underwent Papanicolaou test (PAP test) and high-risk HPV tests. Biopsies were taken from some women and their results were compared. Results: The prevalence of high-risk HPV infection is 24.15%. And the women aged 20-29 years had the highest prevalence (32.3%) compared to 30-70 years (P<0.05). Of the 28,339 women, 1369 (4.83%) had positive PAP test (ASCUS, LSIL, HSIL). Of the 1369 PAP-positive patients, only 16 (1.17%) were negative for HPV test. Of the 1353 patients positive on both tests, 510 (37.7%) had lesions higher than CINII on histology. Of the 1,611 patients who underwent biopsies, 350 underwent the loop electrical excision procedure, with 339 (96%) being positive for HPV test, including 16 with CINI, 48 with CINII/III, 74 with CIS, and 16 with cervical cancer. HPV test had a positive predictive value of 40.7% and a negative predictive value of 100% for higher than CINII. Conclusion: Although HPV test has a burden of cost, considering its high negative predictive value, HPV test should be considered for more useful screening test.
Gas Nozzle Effect on the Deposition of Polysilicon by Monosilane Siemens Reactor
Seung Oh Kang,Uk June Lee,Seung Hyun Kim,Ho Jung You,Kun Park,Sung Eun Park,Jong Hoon Park
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/697653
Abstract: Deposition of polysilicon (poly-Si) was tried to increase productivity of poly-Si by using two different types of gas nozzle in a monosilane Bell-jar Siemens (MS-Siemens) reactor. In a mass production of poly-Si, deposition rate and energy consumption are very important factors because they are main performance indicators of Siemens reactor and they are directly related with the production cost of poly-Si. Type A and B nozzles were used for investigating gas nozzle effect on the deposition of poly-Si in a MS-Siemens reactor. Nozzle design was analyzed by computation cluid dynamics (CFD). Deposition rate and energy consumption of poly-Si were increased when the type B nozzle was used. The highest deposition rate was 1 mm/h, and the lowest energy consumption was 72kWh?kg−1 in this study.
Improvement of ovarian response and oocyte quality of aged female by administration of bone morphogenetic protein-6 in a mouse model
Park Seung S,Park Min J,Joo Bo S,Joo Jong K
Reproductive Biology and Endocrinology , 2012, DOI: 10.1186/1477-7827-10-117
Abstract: Background Advancing female age remains a difficult problem in infertility treatment. Ovarian angiogenesis plays an important role in follicular development and the activation of ovarian angiogenesis has been emerged as a new strategy for the improvement of age-related decline of oocyte quality. BMP-6 affect gonadotropin signals in granulosa cells and it promotes normal fertility by enabling appropriate response to LH and normal oocyte quality. BMP-6 has a potential role in regulation of angiogenesis and regulates the expression of inhibitor of DNA-binding proteins (Ids). Ids involved in the control and timing of follicle selection and granulosa cells differentiation. Especially, Id-1 is well-characterized target of BMP-6 signaling. Therefore, this study investigated whether co-administration of BMP-6 during superovulation process improves ovarian response, oocyte quality and expression of Id-1 and vascular endothelial growth factor (VEGF) in the ovary of aged female using a mouse model. Methods Aged C57BL/6 female mice (26–31 weeks old) were superovulated by injection with 0.1 mL of 5 IU equine chorionic gonadotropin (eCG) containing recombinant mouse BMP-6 at various doses (0, 0.01, 0.1, 1, and 10 ng), followed by injection with 5 IU human chorionic gonadotropin (hCG) 48 h later. Then, the mice were immediately paired with an individual male. The aged control group was superovulated without BMP-6. Young mice of 6–9 weeks old were superovulated without BMP-6 as a positive control for superovulation and in vitro culture of embryos. Eighteen hours after hCG injection, zygotes were retrieved and cultured for 4 days. Both ovaries of each mouse were provided in the examination of ovarian expression of Id-1 and VEGF by reverse transcriptase-polymerase chain reaction, western blot, and immunohistochemistry. Results Administration of 0.1 ng BMP-6 significantly increased the number and blastocyst formation rate of oocytes ovulated and ovarian expression of Id-1 and VEGF compared to aged control mice. These increased levels were comparable to those of young control mice. Conclusions This result suggests that BMP-6 during ovulation induction plays an important role in improvement of oocyte quality and ovarian response of aged female, possibly by regulating of ovarian Id-1 and VEGF expression.
Elevation of Eosinophil-Derived Neurotoxin in Plasma of the Subjects with Aspirin-Exacerbated Respiratory Disease: A Possible Peripheral Blood Protein Biomarker
Seung-Woo Shin, Jong Sook Park, Choon-Sik Park
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066644
Abstract: Aspirin-exacerbated respiratory disease (AERD) remains widely underdiagnosed in asthmatics, primarily due to insufficient awareness of the relationship between aspirin ingestion and asthma exacerbation. The identification of aspirin hypersensitivity is therefore essential to avoid serious aspirin complications. The goal of the study was to develop plasma biomarkers to predict AERD. We identified differentially expressed genes in peripheral blood mononuclear cells (PBMC) between subjects with AERD and those with aspirin-tolerant asthma (ATA). The genes were matched with the secreted protein database (http://spd.cbi.pku.edu.cn/) to select candidate proteins in the plasma. Plasma levels of the candidate proteins were then measured in AERD (n = 40) and ATA (n = 40) subjects using an enzyme-linked immunosorbent assay (ELISA). Target genes were validated as AERD biomarkers using an ROC curve analysis. From 175 differentially expressed genes (p-value <0.0001) that were queried to the secreted protein database, 11 secreted proteins were retrieved. The gene expression patterns were predicted as elevated for 7 genes and decreased for 4 genes in AERD as compared with ATA subjects. Among these genes, significantly higher levels of plasma eosinophil-derived neurotoxin (RNASE2) were observed in AERD as compared with ATA subjects (70(14.62~311.92) μg/ml vs. 12(2.55~272.84) μg/ml, p-value <0.0003). Based on the ROC curve analysis, the AUC was 0.74 (p-value = 0.0001, asymptotic 95% confidence interval [lower bound: 0.62, upper bound: 0.83]) with 95% sensitivity, 60% specificity, and a cut-off value of 27.15 μg/ml. Eosinophil-derived neurotoxin represents a novel biomarker to distinguish AERD from ATA.
Ground beetle (Coleoptera: Carabidae) assemblage in the urban landscape, Korea
Jong-Kook Jung,Seung-Tae Kim,Sue-Yeon Lee,Chang-Kyu Park
Journal of Ecology and Field Biology , 2012,
Abstract: This study was conducted with the intention of clarifying the effects of land-use types on a species of ground beetle’s richness,abundance, and composition; the study focused on urban landscapes. We also selected the potential bioindicatorsclassifying land-use types; eleven sites were selected from an urban landscape in Korea. Overall, land-use types in urbanlandscapes did not appear to cause significant decrease in species richness or the abundance of total ground beetle assemblage.According to habitat preferences, several land-use types and distances from the forest significantly affectedthe species richness and abundance, while the open-habitat species were not affected by these variables. Land-use typeswere classified into two major groups, forest and non-forest areas, based on ground beetle assemblage; several indicators,such as Dolichus halensis halensis and subfamily Carabinae species, were of particular consideration. In conclusion, environmentalchange by anthropogenic disturbance can cause different effects on ground beetle assemblages, and forestspecialists can be negatively affected.
Lane Detection with Moving Vehicles Using Color Information
Nasim Arshad,Kwang-Seok Moon,Seung-Seob Park,Jong-Nam Kim
Lecture Notes in Engineering and Computer Science , 2011,
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