• 제목/요약/키워드: Multiple Impacts

검색결과 398건 처리시간 0.023초

포화도, 간극비 및 응력에 따른 주문진사의 탄성파 속도 (Elastic Wave Velocity of Jumunjin Sand Influenced by Saturation, Void Ratio and Stress)

  • 이정훈;윤태섭
    • 한국지반공학회논문집
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    • 제30권4호
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    • pp.101-106
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    • 2014
  • 관입시험은 한정된 범위에서 1차원적 정보를 얻을 수 있으나, N치는 다양한 지반설계정수와 실험적으로 연관되어 있다. 탄성파를 이용한 비파괴 검사는 역산 과정을 통해 비용 및 시간에 효율적으로 2차원 및 3차원 물성에 대한 지도를 얻을 수 있으며, N치와 탄성파 속도는 간극비, 포화도, 유효응력 등에 의해 좌우된다. 따라서 N치와 탄성파 속도간의 경험적 관계들이 제안되어 왔다. 본 연구는 다양한 간극비와 포화도를 갖는 주문진사에 대해 정지토압조건에서 탄성파를 실험적으로 측정하였다. 그 결과 하중 조건이 간극비 및 포화도에 비하여 가장 영향을 주는 요소로 나타났으며, 간극비와 포화도는 응력-속도 관계의 경향에 영향을 주었다. 각 영향인자간의 관계를 다중회귀분석을 통해 상관식으로 나타내었다.

공 컨테이너 반출 시 발생하는 재취급 횟수 비교 (Comparing Expected Numbers of Re-Handles for Empty Containers During Gate-Out Operation)

  • 이훈;김갑환
    • 한국항해항만학회지
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    • 제42권3호
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    • pp.207-216
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    • 2018
  • 컨테이너 터미널에서 한정된 공간에서 공 컨테이너를 선사별, 컨테이너 종류별로 구분하지 않고 혼적하여 보관하면 장치공간은 효율적으로 활용할 수 있지만 재취급이 증가하는 문제가 발생한다. 본 연구에서는 여러 가지 보관 전략에 따른 장치장에 공 컨테이너가 섞여 있는 상태와 반출 작업에 사용하는 야드 장비에 따라 재취급의 기대 횟수를 추정하는 수식을 유도하고 수치실험을 통하여 비교하였다. 인출비율과 수리비율 변화에 따른 기대 재취급 횟수 변화도 분석하였다. 그리고 장치 규모 변화에 따른 기대 재취급 횟수를 비교하고, 복수 선박의 컨테이너가 혼재된 상태에서 장치비율 및 인출비율 변화에 따른 기대 재취급 횟수를 분석하였다. 공 컨테이너 대상 기대 재취급 횟수를 고려한 효율적인 운영전략에 대한 연구가 필요하다.

UWB 시스템에 의한 WiBro 시스템에서의 간섭영향에 관한 연구 (Analysis of Interference Impact of UWB System on WiBro System)

  • 윤영근;홍헌진;이일규;최익권;곽경섭
    • 한국통신학회논문지
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    • 제31권8A호
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    • pp.814-819
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    • 2006
  • 본 논문에서는 3.1 GHz에서 10.6 GHz 주파수 대역을 사용하면서 실내 및 실외 통신에 적용되는 초 광대역(UWB) 시스템이 OFDM(Orthogonal Frequency Division Multiplexing)을 근간으로 한 2.3 GHz 대 WiBro(Wireless Broad-band )시스템에 미치는 간섭 영향에 대해 분석하였다. 최악의 상황을 고려하여 단일 UWB 간섭의 경우는 최소결합손실(MCL) 방법으로 간섭분석을 수행하였고, 다중 UWB 간섭인 경우는 실제 상황을 고려한 간섭 시나리오를 바탕으로 몬테칼로(MC) 방법으로 간섭 시뮬레이션을 수행하였다. 분석 및 시뮬레이션 결과 두 시스템의 양립성을 보장하기 위해 단일 간섭 원 과 희생(victim) 수신기 사이의 이격 거리는 34.4m 이상이 요구되었다. 또한, 다중 UWB 간섭 원 인 경우에 WiBro 단말기의 최소 throughput 손실을 보장하기 위해 허용할 수 있는 UWB 송신전력 레벨은 약 - 81 dBm / MHz 이하로 요구되었다.

노인의 삶의 질 관련요인 분석 (The Effects of Related Factors on Quality of Life for the Elderly)

  • 강이주
    • 가정과삶의질연구
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    • 제26권5호
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    • pp.129-142
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    • 2008
  • This study examines how economic and psychological characteristics affect the quality of life (QoL) of elderly individuals age 60 and older, who live in the Seoul-metropolitan area. Relationships among socio-demographic status, economic conditions, psychological characteristics, family life, health status, and QoL are examined by t-test and ANOVA(Duncan's test as post hoc multiple comparisons), and the multiple regression analysis is used to estimate QoL determinants in the elderly. The major findings of the study are as follows. First, younger age, higher education levels, better health status, harmonious family relations, higher levels of household income, lower levels of loneliness, and higher self-esteems are related to higher QoL levels. Second, the impacts of factors on QoL are differentiated according to tercile groups that divide monthly allowance of respondents into three categories: below normal (threshold amount below 21MW), near normal (threshold amount between 21MW and 35MW), and above normal (threshold amount above 35MW). For each tercile group, poor health status or higher loneliness have negative effects on QoL, while harmonious family relationship has a positive effect. For the below-normal group, years of education or self-esteem have positive effects, while age or retirement status have negative effects when controlling for other factors. For the near-normal group, being married, or perceived financial insecurity create lower QoL levels, while higher self-esteem increases QoL levels. For the above-normal group, being widowed, employed, or retired have positive effects on QoL, when controlling for other variables. Third, even among elderly with high allowances, the effects of health status and family relationship are significant determinants that explain QoL levels. This result suggests that, for te elderly, poor health status and poor family relationships severely decrease QoL in later life, regardless of economic condition.

청소년의 인터넷 중독현상과 자기통제기대의 구조적 경로모형에 관한 연구 (The Structural Path Model of Adolescents′ Internet Addiction and Expected Self-Control)

  • 박재성
    • 보건교육건강증진학회지
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    • 제21권3호
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    • pp.1-17
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    • 2004
  • The purpose of this study is to evaluate the roles of expected self-control and expected self-control results in explaining adolescents' Internet addiction. In the study model, expectations of self-control and self-control results directly determine Internet addiction and Internet use time meditates the impacts of expectations of self-control and self-control results on Internet addiction. The study subjects are 1,080 middle and high school students in Busan. Stratified cluster sampling is applied by school type and school year. The response rate is 96%(l,037cases). This study develops the scales of expected self-control and expected self-control results. The scales of Internet addiction are devised by using the concept of functional dependency such as salience, withdrawal symptoms, mood modification, tolerance, relapse, and conflict. For verifying the study model, path analysis and multiple regression models are applied for identifying path significants and evaluating confounding effects of control variables, respectively. Moreover, multi partial F-test is performed for selecting the best regression model. Expected self-control is a significant determinant of Internet addiction and Internet use time that also significantly explains Internet addiction. The total effect of expected self-control towards Internet addiction is -.95. The total effect is comprised with the direct effect (-.71) and the indirect effect(-.24). In this result, the direct effect refers a curative effect since expected self-control directly reduces the level of Internet addiction, and the indirect effect refers a preventive effect because self-control can reduce time of Internet use that is a direct determinant of Internet addiction. In the test of the confounding effects of control variables, there are no confounding effects in the models of multiple regression. It implies a robustness of the study model as regards control variables. In conclusion, improving adolescents' expected self-control can control Internet addiction level. This finding implies that a health promotion program for improving expected self-control can be a cost effective method compared to other approaches.

Infection with Opisthorchis viverrini and Use of Praziquantel among a Working-age Population in Northeast Thailand

  • Saengsawang, Phubet;Promthet, Supannee;Bradshaw, Peter
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권5호
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    • pp.2963-2966
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    • 2013
  • Infection with Opisthorchis viverrini (OV) due to eating certain traditional freshwater fish dishes is the principal risk factor for cholangiocarcinoma in Northeast Thailand where the infection is endemic and the incidence of this form of primary liver cancer has been the highest in the world. This paper is the second report of a prospective research project to monitor the impacts of a national liver fluke control programme in a rural community of Northeast Thailand. A sample of 684 villagers aged 20-65 years completed an interview questionnaire and were tested for infection using the Kato thick smear technique. The questionnaire was designed for the exploration of associations between OV infection, previous treatment with praziquantel, and knowledge and beliefs about the drug. The data were analysed using descriptive statistics and multiple logistic regression. The overall prevalence of OV infection was 37.2% and was highest in the 20-35 year age group, in those with a university degree and in those employed in the government sector. As many as 91.8% reported eating fish dishes known to place them at risk of infection. In the multiple regression analysis, previous use of praziquantel and lack of knowledge about whether or not the drug has a protective effect against re-infection were the only factors related to OV infection ($OR_{adj}$= 2.31, 95%CI =1.40-3.79 and $OR_{adj}$= 1.95, 95%CI= 1.24-3.05). The findings were discussed in terms of the possibly unwise dependency on praziquantel as a primary element in a control programme.

시변 페이딩 채널에서 상관관계가 있는 안테나를 사용하는 DS-CDMA 통신 시스템을 위한 개선된 최대가능도 코드 타이밍 추정기 (Improved Code Timing Estimator for DS-CDMA Systems Using Correlated Antennas in Time-Varying Fading Channels)

  • 김상준;정봉식
    • 한국정보통신학회논문지
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    • 제10권5호
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    • pp.910-920
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    • 2006
  • 본 논문에서는 평탄 페이딩과 근거리/원거리 현상이 존재할 때 안테나 어레이를 사용하는 DS-CDMA 신호의 코드 타이밍을 추정하는 문제를 다루고자 한다. 페이딩 과정의 시변 페이딩 특성을 보다 잘 활용할 수 있도록 DS-CDMA 시스템에 대한 희망하는 사용자의 코드 타이밍을 추정하는 최대가능성 알고리즘을 유도한다. 코드 타이밍 추정기의 개발에 있어서 주어진 관찰 비트들을 포함하는 윈도우를 각각의 부-윈도우가 충분히 큰 길이를 갖도록 나눈다. 제안된 방법은 채널 페이딩의 일관성 시간과 연관된 똑같은 크기를 가지는 부-윈도우들을 이용한다. 또한 페이딩 속도를 추정하지 않고 충분히 긴 관찰 비트들을 두 개의 연속적 인 부-윈도우로 나누는 방법을 대안으로 제시한다. 알고리즘의 유도과정은 공간적으로 상관성이 있는 다중안테나를 바탕으로 한다. 공간적인 페이딩 상관성이 제안된 알고리즘의 동기 획득 및 평균 동기 획득 성능에 미치는 영향을 분석한다.

다중충돌 쇼트피닝에서 변형률 속도와 소재 경도가 잔류응력에 미치는 영향에 관한 연구 (Effect of Strain Rate and Material Hardness on Residual Stress in Multiple Impact Shot Peening)

  • 김태우;양조예;나두현;이영석
    • 대한기계학회논문집A
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    • 제35권11호
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    • pp.1369-1375
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    • 2011
  • 쇼트피닝 공정은 쇼트볼이 소재에 충돌을 일으킬 때 생기는 압축잔류응력에 의해 소재의 피로 강도를 향상 시키는데 그 목적이 있다. 본 연구는 변형률 속도 민감도 변화가 압축잔류응력에 미치는 영향을 분석하기 위해서 수행되었다. 본 연구자는 변형률 속도 민감도의 영향을 고려한 쇼트피닝 다중 충돌을 ABAQUS 6.9-1 를 사용하여 모사하였다. 사용된 소재는 AISI 4340 강종이다. 본 연구자는 변형률 속도 민감성이 높은 재료와 낮은 재료를 비교하였다. 결과적으로 변형률 속도 민감성이 증가하면 압축 잔류응력은 감소하였다. 또한 경도가 낮은 소재의 압축잔류응력이 경도가 높은 소재보다 더 크게 발생 하였다.

간호대학생의 자기주장이 간호사와 의사의 협업에 대한 태도에 미치는 영향 (The Impacts of Assertiveness on Attitudes toward Nurse-Physician Collaboration in Nursing Students)

  • 이상민;류영호;김주현
    • 한국간호교육학회지
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    • 제24권4호
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    • pp.326-336
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    • 2018
  • Purpose: This study was conducted to identify the factors affecting nursing students' attitudes toward nurse-physician collaboration. Methods: The subjects were 200 nursing students from a college in K city, and the participants were recruited by posting a recruitment announcement. Data were collected from June 26 to 29, 2018 and analyzed using SPSS 22.0 and descriptive statistics, t-test, ANOVA, Sheff? test, Pearson's correlation coefficients, and hierarchical multiple regression. Results: Attitudes toward nurse-physician collaboration showed a statistically significant difference according to grade, the reflection of opinion within the family, and the number of the counselor in general characteristics. Assertiveness and attitudes toward nurse-physician collaboration showed weak positive correlation (r=.18, p=.011). In hierarchical multiple regression analysis, the most affecting factor was junior grade (${\beta}=.25$), followed by positive assertiveness (${\beta}=.18$) and the number of the counselor (${\beta}=.14$). These variables explained 12.0% of the total variance in attitudes towards nurse-physician collaboration. Conclusion: To create positive attitudes toward collaboration between nurses and physicians in nursing students, various educational programs related to assertiveness on communication skills need to be provided from the lower grades. Also, a multidisciplinary simulation program should be developed and applied to be able to experience the situation of nurses and physicians.

재가노인의 일상활동 어려움, 악력, 일상생활동작이 주관적 건강에 미치는 영향 (The Impacts of Difficulty on Daily Activities, Grip Strength, and Activities of Daily Living on Perceived Health in Community-living Older Adults)

  • 홍손귀령;이윤경;박영선;오은미
    • 근관절건강학회지
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    • 제17권2호
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    • pp.192-202
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    • 2010
  • Purpose: The purpose of the study was to examine the predictive relationships between predictors [(difficulty on daily activities due to arthritis, falls, and pain, grip strength, and activities of daily living (ADLs)], and perceived health in community-living older adults in Korea. Method: A descriptive, cross-sectional survey design was used. Data were obtained from Korean Longitudinal Study of Ageing conducted in 2006. A stratified sample was selected of 5,545 older adults who were over 60 years old for analysis of this study. Descriptive statistics, t-test, Pearson's correlations, and multiple regressions were used. Result: Mean age was 70.27 years (SD=7.27) ranged from 60 and 105 years old. Perceived health was significantly associated with grip strength, and ADL. With multiple regression, all main variables explained 22.1% for perceived health. Difficulty on daily activities due to pain was the strongest predictor on perceived health. Grip strength, ADLs, gender, and difficulty on daily activities due to arthritis and falls were also significant predictors on perceived health. Conclusion: When developing nursing intervention to improve perceived health in older adults, their difficulties on daily activities, grip strength, and ADLs should be assessed.