• ETRI Journal
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• 제40권2호
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• pp.237-245
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• 2018

The Distributed Modulated Wideband Converter (DMWC) is a networking system developed from the Modulated Wideband Converter, which converts all sampling channels into sensing nodes with number variables to implement signal undersampling. When the number of sparse subbands changes, the number of nodes can be adjusted flexibly to improve the reconstruction rate. Owing to the different attenuations of distributed nodes in different locations, it is worthwhile to find out how to select the optimal sensing node as the sampling channel. This paper proposes the spectrum sensing of DMWC based on a Markov random field (MRF) to select the ideal node, which is compared to the image edge segmentation. The attenuation of the candidate nodes is estimated based on the attenuation of the neighboring nodes that have participated in the DMWC system. Theoretical analysis and numerical simulations show that neighboring attenuation plays an important role in determining the node selection, and selecting the node using MRF can avoid serious transmission attenuation. Furthermore, DMWC can greatly improve recovery performance by using a Markov random field compared with random selection.

• 한국정보처리학회논문지
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• 제3권1호
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• pp.55-62
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• 1996

MRNS(Mixed Radix Number System) 네트워크는 슈퍼컴퓨터나 MIMD의 모 델로 널리 쓰이고 있으며 많은 연구가 진행되고 있는 하이퍼큐브의 일반적인 대수학적 모델이다. 본 논문에서는 MRNS 네트워크상에서 메세지의 전송 알고리즘을 연구 하였다. 우리가 이 네트워크상에서 임의의 발신 노드부터 수신노드까지 n개의 패킷들을 동시에 보내려고할 때 이들 패킷들의 빠르고, 안전하게 수신 노도까지 도달하기 위해서는 1번 째의 경로가 다른 모든 경로들로부터 node-disjoint 되어야 한다. 이를 위해 우리는 특수한 메트릭스인 HCLS(Hamiltonian Circuit Latin Squre)[1〕를 응용하여 선형 병렬 전송알고리즘을 개발하였다.

• 한국멀티미디어학회논문지
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• 제8권5호
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• pp.606-617
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• 2005

XML 질의 처리를 위한 XML 문서 트리내 노드들간의 구조적 관계를 효율적으로 찾는 많은 연구들이 수행되었으며 이러한 연구들의 대부분은 노드들의 위치에 기반한 영역 넘버링을 사용하고 있다 그러나 위치 기반의 노드번호 부여 방식은 동일장소에 반복적으로 노드을 삽입할 때 기존 노드번호들의 값 재조정을 필요로 한다. 본 논문에서는 가변길이 문자열을 이용한 버켓단위의 노드번호를 부여함으로써 재조정 노드수를 줄이는 ENN(Extensible Node Numbering) 방법을 제안한다. 또한 기존의 노드번호 부여 방식인 EP(extended preorder)와의 성능 비교를 실시하였다.

• 산업경영시스템학회지
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• 제45권2호
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• pp.20-29
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• 2022

This study intends to present a traffic node-based and link-based accident prediction models using XGBoost which is very excellent in performance among machine learning models, and to develop those models with sustainability and scalability. Also, we intend to present those models which predict the number of annual traffic accidents based on road types, weather conditions, and traffic information using XGBoost. To this end, data sets were constructed by collecting and preprocessing traffic accident information, road information, weather information, and traffic information. The SHAP method was used to identify the variables affecting the number of traffic accidents. The five main variables of the traffic node-based accident prediction model were snow cover, precipitation, the number of entering lanes and connected links, and slow speed. Otherwise, those of the traffic link-based accident prediction model were snow cover, precipitation, the number of lanes, road length, and slow speed. As the evaluation results of those models, the RMSE values of those models were each 0.2035 and 0.2107. In this study, only data from Sejong City were used to our models, but ours can be applied to all regions where traffic nodes and links are constructed. Therefore, our prediction models can be extended to a wider range.

• 한국멀티미디어학회논문지
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• 제17권4호
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• pp.458-465
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• 2014

In this paper, we propose a strategy to distribute the energy consumption over the network. The proposed strategy is based on geographic routing. We use a smart base station that maintains the residual energy and location information of sensor nodes and selects a head node and an anchor node using this information. A head node gathers and aggregates data from the sensor nodes in a target region that interests the user. An anchor node then transmits the data that was forwarded from the head node back to the smart base station. The smart base station extends network lifetime by selecting an optimal head node and an optimal anchor node. We simulate the proposed protocol and compare it with the LEACH protocol in terms of energy consumption, the number of dead nodes, and a distribution map of dead node locations.

• 디지털산업정보학회논문지
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• 제10권1호
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• pp.1-6
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• 2014

In this paper, we propose a CPLD low power algorithm considering the structure. The proposed algorithm is implemented CPLD circuit FC(Feasible Cluster) for generating a problem occurs when the node being split to overcome the area and power consumption can reduce the algorithm. CPLD to configure and limitations of the LE is that the number of OR-terms. FC consists of an OR node is divided into mainly as a way to reduce the power consumption with the highest number of output nodes is divided into a top priority. The highest number of output nodes with the highest number of switching nodes become a cut-point. Division of the node is the number of OR-terms of the number of OR-terms LE is greater than adding the input and output of the inverter converts the AND. Reduce the level, power consumption and area. The proposed algorithm to MCNC logic circuits by applying a synthetic benchmark experimental results of 13% compared to the number of logical blocks decreased. 8% of the power consumption results in a reduced efficiency of the algorithm represented been demonstrated.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.176-179
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• 2002

In recent years, an increasing amount of computer network research has focused on the problem of cluster system in order to achieve higher performance and lower cost. The load unbalance is the major defect that reduces performance of a cluster system that uses parallel program in a form of SPMD (Single Program Multiple Data). Also, the load unbalance is a problem of MPP (Massive Parallel Processors), and distributed system. The cluster system is a loosely-coupled distributed system, therefore, it has higher communication overhead than MPP. Dynamic load balancing can solve the load unbalance problem of cluster system and reduce its communication cost. The cluster systems considered in this paper consist of P heterogeneous nodes connected by a switch-based network. The master node can predict the average execution time of tasks for each slave node based on the information from the corresponding slave node. Then, the master node redistributes remaining tasks to each node considering the predicted execution time and the communication overhead for task migration. The proposed dynamic load balancing uses execution time prediction to optimize the task redistribution. The various performance factors such as node number, task number, and communication cost are considered to improve the performance of cluster system. From the simulation results, we verified the effectiveness of the proposed dynamic load balancing algorithm.

• 대한전자공학회논문지TC
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• 제37권2호
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• pp.7-16
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• 2000

본 논문에서는 p-persistent CSMA 방식의 IEEE 802.11 MAC 계층 프로토콜을 모델링 하였다. 그리고 renewal 이론을 적용하여 수학적으로 분석한 Basic CSMA/CA 프로토콜, CTS/RTS 프로토콜 그리고 은닉 노드를 고려한 Basic CSMA/CA 등의 성능분석모델을 제안하였다. 제안한 분석 모델을 이용하여 throughput을 구한 결과, active 노드 수가 적거나 패킷의 길이가 짧을 때는 Basic CSMA/CA 프로토콜 방식이, active 노드 수가 많거나 패킷의 길이가 길 때는 CTS/RTS 프로토콜 방식이 우수하였다. 또한 active 노드 수가 적은 경우가 많은 경우 보다 은닉 노드의 영향을 적게 받았다.

• Journal of Chest Surgery
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• 제54권5호
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• pp.342-347
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• 2021

Thoracic surgeons need to be aware of several important points regarding intraoperative lymph node dissection during surgery for non-small cell lung cancer with ground-glass opacities. The first point relates to the need for lymph node dissection during sublobar resection. Since even patients undergoing sublobar resection may benefit from lymph node dissection, it should be selectively performed according to adequate indications, which require further study. Second, there seems to be no difference in postoperative morbidity between systematic sampling and systematic dissection, but the survival benefit from systematic dissection remains unclear. The results of randomized controlled trials on this topic are conflicting, and their evidence is jeopardized by a high risk of bias in terms of the study design. Therefore, further randomized controlled trials with a sound design should investigate this issue. Third, more favorable survival outcomes tend to be positively associated with the number of examined lymph nodes. Minimum requirements for the number of examined lymph nodes in non-small cell lung cancer should be defined in the future. Finally, lobe-specific lymph node dissection does not have a negative prognostic impact. It should not be routinely performed, but it can be recommended in selected patients with smaller, less invasive tumors. Results from an ongoing randomized controlled trial on this topic should be awaited.

• Journal of Information Processing Systems
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• 제14권6호
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• pp.1347-1360
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• 2018

Owing to limited energy in wireless devices power saving is very critical to prolong the lifetime of the networks. In this regard, we designed a cross-layer optimization mechanism based on power control in which source node broadcasts a Route Request Packet (RREQ) containing information such as node id, image size, end to end bit error rate (BER) and residual battery energy to its neighbor nodes to initiate a multimedia session. Each intermediate node appends its remaining battery energy, link gain, node id and average noise power to the RREQ packet. Upon receiving the RREQ packets, the sink node finds node disjoint paths and calculates the optimal power vectors for each disjoint path using cross layer optimization algorithm. Sink based cross-layer maximal minimal residual energy (MMRE) algorithm finds the number of image packets that can be sent on each path and sends the Route Reply Packet (RREP) to the source on each disjoint path which contains the information such as optimal power vector, remaining battery energy vector and number of packets that can be sent on the path by the source. Simulation results indicate that considerable energy saving can be accomplished with the proposed cross layer power control algorithm.