• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.23-29
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• 2015

Energy constraints of wireless sensor networks are an important challenge. Data Transmission requires energy. Distance between origin and destination has an important role in energy consumption. In addition, the location of base station has a large impact on energy consumption and a specific method not proposed for it. In addition, a obtain model for location of base station proposed. Also a model for distributed clustering is presented by cluster heads. Eventually, a combination of discussed ideas is proposed to improve the energy consumption. The proposed ideas have been implemented over the LEACH-C protocol. Evaluation results show that the proposed methods have a better performance in energy consumption and lifetime of the network in comparison with similar methods.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1997년도 International Symposium on Fire Science and Technology
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• pp.376-383
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• 1997

Fire experiments were conducted in a real scale room which is assumed to be a residential living room under the various opening conditions and locations of wood crib fire source to study on fire hazard before and after sprinkler activation. Concentrations of oxygen and carbon monoxide, smoke density, and temperature were measured to look into environmental conditions in a room of fire origin. The response time of residential sprinklers was also examined in relation to distance between sprinkler heads and a fire source.

• 전자공학회논문지
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• 제53권3호
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• pp.163-169
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• 2016

클러스터 기반 라우팅 프로토콜로 대표적인 LEACH는 에너지 부하의 공평한 분배를 위해 매 라운드 미리 정해진 확률에 따라 랜덤하게 클러스터 헤드를 선출한다. 하지만 센서 노드가 갖는 현재 에너지 레벨은 고려대상이 아니기에 만일 잔존 에너지가 적은 센서 노드가 클러스터 헤드로 선출된다면 에너지 부하가 큰 헤드의 역할을 완수하지 못하고 사망할 수 있을 것이다. 결국 노드의 첫 사망시간이 매우 빨라져 WSN의 서비스 품질도 나빠질 것이다. 이러한 점에 착안하여 본 논문에서는 클러스터 헤드의 에너지 레벨과 기지국까지의 통신거리를 고려하여 클러스터 내부에 서브 클러스터 헤드를 선택하는 방법을 제안한다. 기존 LEACH에 제안하는 방법을 적용 시 클러스터 헤드의 에너지 부담이 줄어들어 노드의 첫 번째 사망시간이 증가하였고 더욱 증가된 데이터가 기지국에 도착하였으며 이로 인한 WSN의 서비스 품질도 개선되었음을 확인할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3494-3510
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• 2019

Wireless sensor networks encounter energy saving as a major issue as the sensor nodes having no rechargeable batteries and also the resources are limited. Clustering of sensors play a pivotal role in energy saving of the deployed sensor nodes. However, in the cluster based wireless sensor network, the cluster heads tend to consume more energy for additional functions such as reception of data, aggregation and transmission of the received data to the base station. So, careful selection of cluster head and formation of cluster plays vital role in energy conservation and enhancement of lifetime of the wireless sensor networks. This study proposes a new mutation chemical reaction optimization (MCRO) which is an algorithm based energy efficient clustering protocol termed as MCRO-ECP, for wireless sensor networks. The proposed protocol is extensively developed with effective methods such as potential energy function and molecular structure encoding for cluster head selection and cluster formation. While developing potential functions for energy conservation, the following parameters are taken into account: neighbor node distance, base station distance, ratio of energy, intra-cluster distance, and CH node degree to make the MCRO-ECP protocol to be potential energy conserver. The proposed protocol is studied extensively and tested elaborately on NS2.35 Simulator under various senarios like varying the number of sensor nodes and CHs. A comparative study between the simulation results derived from the proposed MCRO-ECP protocol and the results of the already existing protocol, shows that MCRO-ECP protocol produces significantly better results in energy conservation, increase network life time, packets received by the BS and the convergence rate.

• 한국전자파학회논문지
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• 제12권3호
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• pp.409-426
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• 2001

본 논문은 유한차분 시간영역 해석법(Finite-Difference Time-Domain Method)을 사용하여 900 MHz용 휴대폰으로부터 방출된 전파의 인체 두부(頭部)에 흡수된 전력량을 산출하였고, 흡수전력으로 인한 두부내의 온도 상승량을 계산하였다. 이를 위하여 인체두부를 5층 매질로 모델링하였고, 휴대폰은 금속상자에 부착된 모노폴안테나로 모델링하였다. 모델링에 사용된 인체두부와 휴대폰의 크기는 상용의 값을 사용하였다. 사용된 모노폴 안테나의 길이는 8.16 cm이고, 휴대폰의 출력은 상용 900 MHz의 600 mW을 사용하였다. 설정된 모델링하에서 인체의 위해(危害)정도를 알려주는 지수는 1 g, 10 g 평균 北 흡수율(SAR-Specific Absorption Rate)의 분포를 계산하였고 이에 따른 1g, 10 g 평균 온도 상승량을 계산하였다. 그 결과 비흡수율이 최대가 되는 지점은 인체 두부의 피부 부분이었고 최대 온도 증가 위치는 이보다 안쪽부분에서 나타났다. 인체 두부와 휴대폰의 이격거리에 따른 SAR과 온돈 상승량을 계산하였다.

• Journal of Animal Science and Technology
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• 제53권1호
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• pp.23-27
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• 2011

본 연구는 2005년 1월 1일부터 2009년 12월 31일까지의 제주경마공원과 과천경마공원에서 수집한 경주마의 경주기록 85,732개를 이용하여 제주마 및 한라마의 경주개선 활용을 위한 경주능력 수준향상 방안 수립시 기초자료를 제공하는데 그 목적이 있으며, 얻어진 결과는 다음과 같다. 지난 5년간 제주경마공원에서 총 2,892두의 경주마가 활약하였으며, 이중 제주마는 338두로 전체 경주마의 11.7%를 차지하였다. 제주마와 한라마의 평균 체중은 267 kg과 287 kg으로 더러브렛 평균 체중 460 kg 대비 약 58%와 62%를 나타내었다. 주파기록에 대한 반복력은 제주마 0.26~0.66, 한라마 0.34~0.68, 더러브렛은 0.37~0.60의 범위로 추정되었고 경주거리가 증가할수록 반복율은 감소하는 경향을 나타내었으며, 평균 반복율은 각각 0.54, 0.56과 0.50이었다. 1,000 m 경주거리의 주파기록에 있어서 더러브렛과 제주마는 24.33초, 더러브렛과 한라마는 10.81초의 기록차이가 나타났으며, 제주마와 한라마의 기록차이는 13.52초였다. 1000 m 경주거리에서 주파기록에 대한 한라마의 경주능력은 제주마에 비하여 55.6% 향상되는 것으로 조사되었다.

• 제어로봇시스템학회논문지
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• 제13권9호
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• pp.920-926
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• 2007

Establishing a fixed path for the message delivery through a wireless network is impossible due to the mobility. Among the number of routing protocols that have been proposed for wireless ad-hoc networks, the AODV(Ad-hoc On-demand Distance Vector) algorithm is suitable in the case of highly dynamic topology changes, along with ZigBee Routing(ZBR), with the exception of route maintenance. Accordingly, this paper introduces a routing scheme focusing on the energy efficiency and route discovery time for wireless alarm systems using IEEE 802.15.4-based ZigBee. Essentially, the proposed routing algorithm utilizes a cluster structure and applies ZBR within a cluster and DSR (Dynamic Source Routing) between clusters. The proposed algorithm does not require a routing table for the cluster heads, as the inter-cluster routing is performed using DSR. The performance of the proposed algorithm is evaluated and compared with ZBR using an NS2 simulator. The results confirm that the proposed Cluster-based AODV (CAODV) algorithm is more efficient than ZBR in terms of the route discovery time and energy consumption.

• 한국IT서비스학회지
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• 제9권3호
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• pp.95-106
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• 2010

Many researches have been performed to increase energy-efficiency in wireless sensor networks. One of primary research topics is about clustering protocols, which are adopted to configure sensor networks in the form of hierarchical structures by grouping sensor nodes into a cluster. However, legacy clustering protocols do not propose detailed methods from the perspective of implementation to determine a cluster's boundary and configure a cluster, and to communicate among clusters. Moreover, many of them involve assumptions inappropriate to apply those to a sensor field. In this paper, we have designed and implemented a new T-Clustering (Top-down Clustering) protocol, which takes into considerations a node's density, a distance between cluster heads, and remained energy of a node all together. Our proposal is a sink-node oriented top-down clustering protocol, and can form uniform clusters throughout the network. Further, it provides re-clustering functions according to the state of a network. In order to verify our protocol's feasibility, we have implemented and experimented T-Clustering protocol on Crossbow's MICAz nodes which are executed on TinyOS 2.0.2.

• Journal of Animal Science and Technology
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• 제63권1호
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• pp.25-35
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• 2021

The purpose of this study is to estimate the single nucleotide polymorphism (SNP) effect for pH values affecting Berkshire meat quality. A total of 39,603 SNPs from 1,978 heads after quality control and 882 pH values were used estimate SNP effect by single step genomic best linear unbiased prediction (ssGBLUP) method. The average physical distance between adjacent SNP pairs was 61.7kbp and the number and proportion of SNPs whose minor allele frequency was below 10% were 9,573 and 24.2%, respectively. The average of observed heterozygosity and polymorphic information content was 0.32 ± 0.16 and 0.26 ± 0.11, respectively and the estimate for average linkage disequilibrium was 0.40. The heritability of pH45m and pH24h were 0.10 and 0.15 respectively. SNPs with an absolute value more than 4 standard deviations from the mean were selected as threshold markers, among the selected SNPs, protein-coding genes of pH45m and pH24h were detected in 6 and 4 SNPs, respectively. The distribution of coding genes were detected at pH45m and were detected at pH24h.

• PNF and Movement
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• 제18권3호
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• pp.305-313
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• 2020

Purpose: The aim of this study was to investigate the relationship between a functional evaluation model and the Fugl-Meyer assessment (FMA) scale in evaluating the upper extremities of stroke patients Methods: Thirty-eight stroke patients were evaluated using the FMA and performed reaching and grasping motions using a three-dimensional motion analysis (Qquas 1 series, Qualisys AB, Sweden). The participants sat on a chair with a backrest. The position of the cup was located at a distance of 80% to the front arm length. The markers were attached to the sternum, acromion, elbow lateral epicondyle, ulnar styloid process, three metacarpal heads, and the distal phalanges of the thumb and index finger. The variables of the correlation between the functional evaluation model and the FMA scale were analyzed. Multiple regression (stepwise) was used to investigate the effect of the kinematic variables. Results: A significant negative correlation was found between the movement time (p < 0.05), movement unit (p < 0.05), and trunk displacement values (p < 0.05) in the FMA total scores, while a positive correlation was found between the peak velocity (p < 0.05) and maximum grip aperture values (p < 0.05). As a result of the multiple regression analysis, the most significant factor was the movement unit, followed by the general movement assessment and trunk displacement. The explained FMA total score value was 62%. Conclusion: This study presents a new functional evaluation model for assessing the reaching and grasping ability of stroke patients. The factors of the proposed functional evaluation model showed significant correlations with the FMA scale scores and confirmed that the new functional evaluation model explained the FMA by 67%. This suggests a new functional evaluation model for reaching and grasping stroke patients.