• 한국통신학회논문지
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• 제32권10A호
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• pp.1004-1014
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• 2007

In sensor networks, it is crucial to reliably and energy-efficiently deliver sensed information from each source to a sink node. Specifically, in mobile sink (user) applications, due to the sink mobility, a stationary dissemination path may no longer be effective. The path will have to be continuously reconfigured according to the current location of the sink. Moreover, the dynamic optimal path from each source to the sink is required in order to reduce end-to-end delay and additional energy wastage. In this paper, an Adaptive Reversal Optimal path Tree (AROT) protocol is proposed. Information delivery from each source to a mobile sink can be easily achieved along the AROT without additional control overhead, because the AROT proactively performs adaptive sink mobility management. In addition, the dynamic path is optimal in terms of hop counts and the AROT can maintain a robust tree structure by quickly recovering the partitioned tree with minimum packet transmission. Finally, the simulation results demonstrate that the AROT is a considerably energy-efficient and robust protocol.

• 한국정보통신학회논문지
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• 제20권10호
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• pp.2001-2006
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• 2016

감마선 공간 탐지 장치는 감마선원을 스캔하여 영상화 한 후 스테레오 영상처리기술을 적용하여 탐지선원까지의 거리를 측정한다. 또한 실제 공간의 방사선원에 대한 분포 정보를 제공해 준다. 본 논문에서는 감마선 탐지장치가 3차원 공간상에서 장치로부터 선원을 찾기 위해 스캔하는 탐지 시간을 단축 시킬 수 있도록 감마선 탐지 고속화 알고리즘을 구현하였다. 그리고 감마선 조사 시험장에서 실험을 통해 그 성능을 검증하였다. 탐지시험 결과 고속 탐지를 위한 알고리즘을 적용할 경우 단일선원을 탐지할 경우 좌 우 스테레오 영상 획득 시보다 약 35% 의 탐지 시간을 단축시킬 수 있음을 확인하였다. 또한 사용자에게 방사선 공간분포 정보를 효율적으로 전달하기 위한 감마선원 분포의 입체 가시화를 구현하여 방사선원에 대한 정보를 제공할 수 있도록 하였다.

• 대한전자공학회논문지SD
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• 제44권10호
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• pp.61-66
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• 2007

본 논문에서는LCD (Liquid Crystal Display) source driver IC에서 사용되는 고전압 op-amp의 출력 편차를 개선하기 위하여 전압 이득을 향상한 CMOS rail-to-rail 입/출력 op-amp를 제안하였다. 제안된 op-amp는 15 V 이상의 고전압 MOSFET의 과도한 channel length modulation에 의한 전압 이득의 감소로 offset 전압이 커지는 문제를 해결하기 위하여 cascode 구조를 갖는 floating current source 및 class-AB control단을 채용하고 있다. 제안된 op-amp는 HSPICE 시뮬레이션을 통하여 전압 이득이 기존 대비 30 dB 향상됨을 확인하였으며, onset 전압은 기존 6.84 mV에서 $400\;{\mu}V$ 이하로 개선됨을 확인하였다. 또한, 제안된 op-amp가 적용된 LCD source driver IC의 실측 결과 출력 편차는 기존 대비 2 mV 향상됨을 확인하였다.

• 한국지능시스템학회논문지
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• 제13권2호
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• pp.222-230
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• 2003

의료 시스템이 개발되면 시스템이 사용하는 knowledge source의 신뢰도가 시스템의 수행능력에 큰 영향을 미치게 되므로, knowledge source의 신뢰도를 검증해야한다. 본 논문은 의료 시스템 CLINAID의 knowledge source의 신뢰성 조사에 대한 연구의 방법과 결과를 발표하였다. 그 방법으로는 CLINAID에 사용된 Cardiovascular body system 데이터에 fuzzy relational method를 적용하여 구조적 분석을 통해 만들어진 인공의 syndrome을 knowledge base에 저장되어있는 의료 전문가의 syndrome과 비교하였다. 7 가지 fuzzy implication operator를 사용하여 거의 비슷한 결과들을 산출해 냈으며, 그 결과들이 전문가가 제공한 syndrome과 거의 일치하였다.

• Asia pacific journal of information systems
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• 제27권2호
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• pp.77-98
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• 2017

The development of mobile social networking service (SNS) triggers the growth of social commerce industry. Customers rely considerably on electronic word of mouth (eWOM) to make purchasing decisions. Thus, SNS is an important commercial platform that offers attractive opportunities and challenges to firms. This study sheds light on the role of SNS as a social commerce platform by focusing on WeChat, the most popular SNS in China. This study identifies three different types of trust based on SNS that customers perceive in the context of social commerce. These types of trust are contents trust, source trust, and platform trust. This study suggests the antecedents and consequences of each trust. Our results prove that eWOM intention relies on contents trust and source trust, whereas purchase intention depends on contents trust, source trust, and platform trust. This study also finds that contents trust is positively influenced by source trust and platform trust. Finally, the result verifies the key antecedents of each trust, namely, vividness and timeliness for contents trust, competence, benevolence, and integrity for source trust, and instrumental need and social need for platform trust. The discussion and implications on the findings are provided.

• 한국대기환경학회지
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• 제31권6호
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• pp.508-519
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• 2015

The objective of this study was to quantitatively estimate $PM_{2.5}$ source contribution in Gyeongsan. Ambient $PM_{2.5}$ samples have been collected on zefluor, quartz and nylasorb filter by $PM_{2.5}$ samplers of cyclone method from September 2010 to December 2012. Collected samples were analyzed for determining 17 inorganic elements, 8 ions, and 8 carbon components after pretreatment. Based on these chemical information, the PMF model was applied to estimate the quantitative contribution of air pollution sources. The results of the PMF modeling showed that the sources were apportioned by biomass burning source (15.5%), secondary sulfate source (16.0%), industry source (10.4%), soil source (7.0%), gasoline source (9.1%), incinerator source (10.4%), diesel emission source (11.0%), and secondary nitrate source (20.6%), respectively. To analyze local source impacts from various wind directions, the CPF analysis were performed using source contribution results with the wind direction values measured at the site.

• Smart Structures and Systems
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• 제29권6호
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• pp.777-783
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• 2022

Even though several deep learning-based methods have been applied in the field of acoustic source localization, the previous works have only been conducted using the two-dimensional representation of the beamforming maps, particularly with the planar array system. While the acoustic sources are more required to be localized in a spherical microphone array system considering that we live and hear in the 3D world, the conventional 2D equirectangular map of the spherical beamforming map is highly vulnerable to the distortion that occurs when the 3D map is projected to the 2D space. In this study, a 3D deep learning approach is proposed to fulfill accurate source localization via distortion-free 3D representation. A target function is first proposed to obtain 3D source distribution maps that can represent multiple sources' positional and strength information. While the proposed target map expands the source localization task into a point-wise prediction task, a PointNet-based deep neural network is developed to precisely estimate the multiple sources' positions and strength information. While the proposed model's localization performance is evaluated, it is shown that the proposed method can achieve improved localization results from both quantitative and qualitative perspectives.

• Journal of Preventive Medicine and Public Health
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• 제34권4호
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• pp.389-398
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• 2001

Objectives : To investigate the information searching behavior of health care consumers according to sociodemographic characteristics. Methods : A questionnaire survey was conducted of 1,507 persons who were selected through a multi-stage stratified area cluster sampling of the Republic of Korea, excluding the province of Jeiu-do. Personal were conducted through a door-to-door survey between 27 July and 10 August 1999. Results : 80.5% of respondents used more than one source of information and those $40\sim59$ years of age, female, a housewife or student and those who claimed a religion demonstrated more active information searching behavior. A personal informer was used significantly more in those $20\sim39$ years old, female, and those who claimed a religion. Clerical workers, those with post-secondary education and a monthly income greater than 2,000,000 won ($1500) were more actively used a public informer. Low socioeconomic status and older persons used an experimental informer when they chose a health care institution. Conclusion : Regardless of the sociodemographic characteristics, personal and experimental informers were the most useful source of information. Because appropriate information was not easy to obtain, the health care consumer was dependent upon word-of-mouth communication(personal informer) when using health care services.

• 한국대기환경학회지
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• 제13권4호
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• pp.285-296
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• 1997

The suspended particulate matters had been collected on quartz fiber fiters by a cascade impactor having 9 size stages for 4 years (Sep. 1991 to Dec. 1995) in Kyung Hee University-Suwon Campus. Membrane filters were used to collected the particulate matters on each stage. The weight concentration on each stage was obtained by a microbalance and further chemical element levels were determined by an x-ray fluorescence system. Based on these chemical information, our study focused on applying the target transformation factor analysis (TTFA), a receptor model, to identify aerosol sources and to apportion quantitatively their mass contribution. There are total of 63 ambient data sets. Each data set consists of the 8 size-ranged subdata sets characterized by 16 elemental variables. By the results, four to five sources were extracted from each size range and some sources reappeared in other size ranges. Then total of 8 source profiles were statistically generated from all the ranges, such as oil burning source, soil source, field burning source, gasoline related source, coal burning source, marine source, glass related source, and unknown sources. Apportioning aerosol mass to each source was intensively examined by investigating emission inventories near the study area. The results showed that soil particle source was the most significant contributor. However, coal and oil burning sources were the major anthropogenic ones. The study finally proposed some air quality control strategies to achieve the clean air quality in Suwon area.

• 한국정보과학회논문지:정보통신
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• 제36권6호
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• pp.528-535
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• 2009

본 논문에서는 IEEE 802.11 환경에서 무선 협력 통신을 이용하여 성능을 향상 시키는 방법에 대해 제안한다. 기존 협력 통신 알고리즘은 소스(source)와 AP(Access Point) 사이에 1개의 릴레이(relay)를 두어 수행한 2 홉 릴레이(hop relay) 방식으로, 이는 알맞은 릴레이를 찾을 수 없는 경우가 발생하므로 보완이 필요하다. 본 논문에서는 AP에서 네트워크 정보(노드 사이 전송률, 노드와 AP 사이 전송률)를 관리하여 릴레이 선정에 이 네트워크 정보를 이용한다. 이 정보를 이용하여 AP는 1개 이상의 릴레이를 선정하여 소스와 주위 노드에게 선정된 릴레이를 알리고 소스에서 데이터를 전송할 때 이 릴레이를 통해 협력 통신을 하도록 한다. 이러한 협력 통신 방법은 데이터 전송의 효율성을 높인다. 또한 본 논문에서는 소스의 데이터를 전송한 릴레이는 소스의 데이터를 전송한 후에 자신의 데이터 또한 전송할 수 있는 기회를 가지도록 하여 소스 데이터를 대신 전송하여 소비된 노드의 자원을 만회할 수 있는 기회를 가지게 한다. 이로써 제안된 방법을 이용하면 노드의 자원 소비를 보완함은 물론 전체 네트워크의 성능(throughput)을 향상시킬 수 있다.