• Title/Summary/Keyword: p-center 문제

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Min-Sum ${\lambda}$ Discrete 2-Center Problem (거리의 합이 최소가 되는${\lambda}$ 이산 2-중심 문제)

  • Shin, Chan-Su;Wolff, Alexahder
    • Journal of KIISE:Computer Systems and Theory
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    • v.29 no.6
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    • pp.340-345
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    • 2002
  • In this paper, we deal with the following facility location problem. Given a set P of n points in the plane, find two (discrete) centers p and q in P that minimize the sum of there distance plus the distance of any other point to the closer center. In this paper, we propose an Ο(n$^2$1ogn)-time algorithm to compute the two centers.

Optimal Location of Expressway Patrol Vehicle Stations Using Maximum Covering and Weighted p-Center Problems (Maximum Covering 문제와 Weighted p-Center 문제를 이용한고속도로 순찰대 최적 입지 결정)

  • Kim, Myeonghyeon;Kim, Hyo-Seung;Kim, Dong-Kyu;Lee, Chungwon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.1
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    • pp.43-50
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    • 2013
  • This paper aims to determine the optimal location of expressway patrol vehicle stations that minimizes additional troubles caused by the delay of crash treatments. To do this, we formulate a maximum covering problem and a p-center problem weighted by crash frequency, using the shortest distance as the criteria for allocating service district, and we employ the Lagrangian relaxation algorithm to solve the former and Daskin's heuristic algorithm to solve the latter, respectively. Based on crash data of Korean expressways, the results from the proposed models are compared with the current location of patrol vehicle stations by using several indices as the level of service for crash treatment, such as maximum crash-weighted distance, average crash-weighted distance, and average access distance. The results show that the proposed models improve average access distance and time by about 10km and 10min, respectively. When allocation for service district is changed only with the fixed current location, the level of service can be also improved. The models and results proposed in this paper can contribute to improving the level of service for crash treatment on expressways. They can also provide the theoretical basis on the location decision for other various emergency facilities, and the allocation decision for floating service districts according to time-period crash data.

Factors Influencing on Problem Drinking in Foreign Workers for Drinking Motives, Acculturative Stress (외국인 근로자의 음주동기, 문화적응 스트레스가 문제음주에 미치는 영향)

  • Ha, Yeong-Mi;Park, Ki-Soo;Cho, Jeong-Eui
    • Journal of Digital Convergence
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    • v.16 no.2
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    • pp.225-234
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    • 2018
  • The purpose of this study was to examine relationships among drinking motives, acculturative stress and problem drinking, and then to identify the influencing factors of problem drinking in foreign workers. A total of 120 foreign workers recruited from two shipyards in G city. Self-reported questionnaire survey was conducted from October to December, 2016. As a result, a rate of problem drinking in foreign workers was 39.2%. According to the multiple regression analysis, their problem drinking was significantly influenced by social motives (${\beta}=.368$ p=.003) and conformity motives (${\beta}=.337$ p=.005) as a subscale of drinking motives and homesickness (${\beta}=-.197$, p=.009) as a subscale of acculturative stress, explained 39.5% of the total variance (F=26.849, p=.000). Based on our results, an education program using drinking motives, acculturative stress should be developed to prevent problem drinking in foreign workers.

Effects of Foot Bath Therapy on Menopausal Symptoms and Sleep in Women in Their 50s (족욕요법이 50대 여성의 갱년기 증상 및 수면에 미치는 영향)

  • Jeon, Gesam;Jeon, Yowon;Kim, Wonbin
    • Journal of Naturopathy
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    • v.9 no.2
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    • pp.57-61
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    • 2020
  • Purpose: Purpose: This study was to study the effect of foot bathing on menopausal symptoms and sleep disorders in female subjects in their 50s with menopausal symptoms. Methods: After 12 weeks of foot bath therapy three times a week, pre- and post-menopausal signs were measured. Results: Subjects with hot flashes, heart discomfort, sleep problems, depression, irritability, anxiety, physical and mental fatigue, sexual problems, urination problems, vaginal dryness, and joint and muscle discomfort significantly improved after than before(p < .001). Subjective sleep quality, sleep incubation period, sleep duration, sleep disturbance score, sleep drug use, and sleep dysfunction significantly decreased after foot bath than before(p < .001). Habitual sleep efficiency increased considerably. Conclusions: The subjects showed overall improvement in menopausal symptoms and sleeping quality after a foot-bath. Therefore, foot bath therapy is evaluated as a natural healing therapy suitable for improving menopausal symptoms and sleep.

Triangular lattice Deployment Patterns for p-Coverage and q-Connectivity in Wireless Sensor Networks (무선 센서 네트워크에서 다중 커버리지와 연결성을 위한 삼각 배치 패턴)

  • Kim, Yong-hwan;Kim, Chan-Myung;Han, Youn-Hee
    • Proceedings of the Korea Information Processing Society Conference
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    • 2011.11a
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    • pp.662-664
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    • 2011
  • 무선 센서 네트워크에서 관심지역이 각 센서에 의하여 얼마나 잘 센싱되는지의 정도에 대한 커버리지(coverage)와 센서에 의하여 센싱된 데이터를 싱크노드까지 얼마나 잘 전달될 수 있는지의 정도에 관한 연결성(connectivity)은 중요한 연구 분야이다. 이와 관련하여 본 논문에서는 센서 네트워크에서 p-coverage와 q-connectivity ($q{\leq}6$)를 만족하는 최적의 센서 배치패턴 문제에 관한 연구 결과를 기술한다. 특히, 1-coverage의 경우 최적이라 알려진 삼각 격자 패턴에 대하여 p-coverage와 6-connectivity을 만족하도록 하는 배치 방법을 제시한다.

RELATIONSHIP OF MOTHERS' SELF-PERCEPTION WITH PERCEPTION OF CHILDREN'S PROBLEMS - FOCUSING ON VALIDITY SCALES OF MMPI & KPI-C - (어머니의 자기 지각 성향과 자녀 문제에 대한 지각 성향간의 관계 - MMPI와 KPI-C의 타당도 척도를 중심으로 -)

  • Kim, Keun-Hyang;Jung, Yoo-Sook;Hong, Sung-Do;Kim, E-Yong;Kim, Ji-Hae
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.9 no.2
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    • pp.174-179
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    • 1998
  • Objective:Present study investigated the relationship between mothers' self-perception and perception of children's problems. Method:Subjects were 63 children, mothers, who visited child & adolescent psychiatric clinic. Their mothers completed Minnesota Mulpiphasic Personality Inventory(MMPI) & Korean Personality Inventory for Children(KPI-C). Correlation between validity scales of mothers' MMPI and validity scales of KPI-C was analysed, and then we divided subjects into two group(High & Low Group) according to the MMPI validity scales, and compared KPI-C's validity scales by student t-test. Result:There were significant positive correlation(r=.30) between K scale of MMPI and L scale of KPI-C, significant negative correlation(r=-.32) F scale of MMPI and L scale of KPI-C. The Means of T scores did show significant difference according to MMPI F, K scales in KPI-C L scale, to MMPI L scale in KPI-C F scale. Conclusion:These results indicated that defensive mothers tend to perceive her child's problems more defensively. However mothers who exaggerate their problem more severely, do not exaggerate their children's problem. Therefore, these result suggested that we should be careful not to underestimate children's problem whose mother elevated in K scale of MMPI.

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Mediating Effect of Depression on the Relationship between Gambling Severity and Cognitive Distortion: Secondary Data Analysis of Korea Center on Gambling Problems (도박문제 심각도와 도박인지오류 간 우울의 매개효과: 도박문제치료 지역센터 자료 이차분석)

  • Lee, Keelyong;Hong, Jungah
    • Journal of Korean Academy of Psychiatric and Mental Health Nursing
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    • v.27 no.4
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    • pp.370-379
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    • 2018
  • Purpose: The purpose of this study was to test the mediating effect of depression on the relationship between gambling severity and cognitive distortion in Koreans with a gambling disorder. Methods: Secondary data from a comprehensive assessment of problematic gambling between 2015 and 2017 on Korea Center on Gambling Problems were used. The subjects in this study were 254 Koreans with that gambling disorder. Data were collected with self-report structured questionnaires which included individual characteristics, the Korean version of Problem Gambling Severity Index, the Center for the Epidemiologic Studies Depression, and the Gambling Related Cognitions Scale. Data were analyzed by using descriptive statistics, independent t-test, one-way ANOVA with the $Scheff{\acute{e}}$ test, Pearson's correlation coefficients, and a mediation analysis of the Baron and Kenny method with the SPSS 22.0 program. Results: Significant correlations emerged among the three variables, gambling severity, depression, and cognitive distortion. Depression exerted a partial mediating effect (${\beta}=.20$, p<.001) on the relationship between gambling severity and cognitive distortion (Sobel test: z=2.33, p=.012). Conclusion: Based on this study's findings, nursing intervention programs focused on managing gambling severity and decreasing depression are highly recommended to alleviate cognitive distortion in people with a gambling disorder.

Implementation of P2P Standard Group Formation in WiFi Direct for Direct Communication Services between Internet-of-Things Gateways (사물인터넷 게이트웨이 간의 직접통신 서비스를 제공하기 위한 와이파이 다이렉트 P2P Standard Group Formation 구현)

  • Park, Yungi;Han, Kwonhee;Seo, Jeongwook;Kim, Hyunsik;Park, Yongsuk
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.436-438
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    • 2015
  • In this paper, a P2P Standard Group Formation (P2P-SGF) method in Wi-Fi Direct is presented to provide direct communication services between Internet-of-Things (IoT) gateways. Generally, network traffic congestion and speed reduction problems are caused when transmitting mass data as well as measured data from many sensors between IoT gateways via an Access Point (AP). For solving these problems, it is required to implement Wi-Fi Direct efficiently transmitting mass data between IoT gateways without passing through the AP. The implemented P2P-SGF method basically performs Discovery, GO (Group Owner) Negotiation, WPS (Wi-Fi Protected Setup) Provisioning, and Address Configuration. Especially, it supports the DLNA (Digital Living Network Alliance) service function for sharing mass data between IoT gateways. Some experimental results verify that it can successfully share large video files.

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Performance evaluation of spNFS on a small scale cluster system (소규모 클러스터 시스템에서의 spNFS 성능 평가)

  • Kwangho Cha;Sungho Kim;Sangdong Lee
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.11a
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    • pp.940-942
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    • 2008
  • 분산되어 있는 스토리지 자원을 하나의 클러스터로 구성하여 분산 파일 시스템으로 구성하고자 하는 경우, 기존의 네트워크 파일 시스템만을 이용하기에는 여러 가지 제약이 존재한다. 특히 Parallel Striped Access는 IO데이터를 스토리지에 나누어 분산시키고 클라이언트가 직접 접근하는 방식으로 병렬 파일 시스템과 같은 HPC 용 특수 파일 시스템에서는 이미 사용되는 기법이나, 일반적인 시스템을 대상으로 한 표준안의 부재가 제약이 된다. pNFS(Parallel NFS)는 이러한 문제를 해결하기 위해서 제시되는 새로운 NFS 기술이다. 본 연구에서는 pNFS의 연구 동향과 더불어 소규모 클러스터 시스템에서 나타나는 성능적 특징을 조사하였다.