• 제목/요약/키워드: parts reliability

검색결과 881건 처리시간 0.024초

Revealing the Spatial Distribution of Inorganic Elements in Rice Grains

  • Jeon, Ji Suk;Choi, Sung Hwa;Lee, Ji Yeon;Kim, Ji A;Yang, Young Mi;Song, Eun Ji;Kim, Jae Sung;Yang, Jung Seok;Kim, Kyong Su;Yoo, Jong Hyun;Kim, Hai Dong;Park, Kyung Su
    • Bulletin of the Korean Chemical Society
    • /
    • 제35권11호
    • /
    • pp.3289-3293
    • /
    • 2014
  • Femtosecond laser ablation (fs LA) was used in this study to identify pollution by heavy metals and the distribution of elemental nutrients at different rice milling ratios. Polished rice (degrees of milling of 3, 5, 7, 9, and 11) was collected from major Korean supermarkets and one sample thereof was selected. An internal quality control experiment was conducted using a rice flour certified reference material from the Korea Research Institute of Standards and Science (KRISS CRM) for the evaluation of the efficacy. To assess the effectiveness of the analysis method, the reliability was validated using a food analysis performance assessment scheme (FAPAS), with chili powder serving as an external quality control. The results of the analysis of the inorganic elements Ti, Ca, Al, Fe and Mn in white and brown rice with degrees of milling of 3, 5, 7, 9 and 11 using ICP-MS, ICP-OES and AAS revealed contents of 0.40, 49.2, 2.43, 5.36 and 10.3 mg/kg in white rice and 0.59, 78.0, 7.52, 11.0 and 18.5 mg/kg in brown rice, respectively. Among the elements, there were remarkable differences in the measured contents. By comparing the contents of the elements at different degrees of milling, Ti, Co, As, Ca, Al, Cu, Fe, and Mn were determined to be distributed on the surface of the rice grains, whereas the contents of Cd and Pb increased toward the center of the rice grains, and Si was evenly distributed. After the quantitative analysis of rice samples polished to different degrees of milling, Ca and Al, which were contained in large amounts, and Si were analyzed with specificity by fs LA. The results show that Ca and Al were distributed in the rice husk (protective covering of rice) and Si was distributed in all parts of the rice.

산욕초기 어머니 역할획득을 위한 신생아실 간호사 역할수행에 관한 연구 (Nursery Room Nurses′ Role Performance for Maternal Role Attainment of Mothers at Early Postpartum Period)

  • 이영은;박춘화;박금자;김영순;박봉임
    • Child Health Nursing Research
    • /
    • 제4권2호
    • /
    • pp.177-192
    • /
    • 1998
  • The early postpartum period is crucial toward in recovery from childbirth and attainment of the maternal role. Maternal role attainment is a complex social and cognitive process of stimulus-response accomplished by learning. Helping for maternal role attainment is one of nursing goals in the early postpartum period. Based on King's conceptual framework for nursing, this study was planned as descriptive correlation study to determine the significant differences of the degree of nursery room nurses' role performance according to several variables of personal, interpersonal, and working system of nurses in nursery room. The purpose of this study was to contribute to the planning of nursing care to help maternal role attainment of the early postpartum period of mothers and to the development of relevant nursing theory. The data were collected from Feb. 3 to 28 by questionnaires with 273 nurses in nursery room. The instruments for this study were consisted of four parts : 21 questions for rot performance of nurse. 37 questions for personal system of nurse including 31 questions for role perception of nurse : 65 questions for interpersonal system including 63 questions for job stress of nurses , 18 questions for working system of nurse. The toos to measure role performance and role perception, and job stress of nurse were tested for internal reliability. Cronbach's Alphas were 0.9612, 0.9058, and 0.9649. The data were analysed by using in S.A.S. computerized program and included percentage, t-test, ANOVA Pearson Correlation Coefficient, and Duncan multiple range test. The conclusions obtained from this study are summerized as follows : 1. The mean score of the items of role performance was 2.12(SD=0.55) in Likert's 4 points scale. 2. The degree of role performance was significantly different according to role perception(p=0.0001), age (p=0.006), educational background(p=0.002) , and certificate of midwife (p=0.03) among variables of personal system of subjects. 3. The degree of role performance was significantly different according to job stress (p=0.0001) and numbers of children(p=0.006) among variables of interpersonal system of subjects. 4. The degree of role performance was significantly different according to having opportunities for baby(p=0.03), the degree of flexibility to bring baby to mother's room(p=0.046), the scope of visitor for baby(p=0.016) , the degree of flexibility of visiting for baby (p=0.049) , the degree of participation of nurse in establishing visiting rules(p=0.017), existence and/or nonexistance of rules for breast feeding(p=0.010) , existence and/or nonexistance of education for breast feeding (p=0.009), existence and/or nonexistance of breast feeding room(p=0.013) , concert methods for breast feeding (p=0.003), working place (p=0.0001), and career(p=0.019) among variables of personal system of subjects.

  • PDF

위상간섭을 이용한 사축식 액셜 피스톤 펌프의 압력 맥동 감소 (A Reduction in Pressure Ripples of Axial Piston Pumps of Bent Axis by Phase Interface)

  • 김경훈;박경석;장주섭;김봉환;이규원;손권;신민호
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2003년도 춘계학술대회 논문집
    • /
    • pp.1261-1265
    • /
    • 2003
  • Axial piston pumps of bent axis have been commonly used in hydraulic systems because of high pressure level. best efficiency, low shear force on pistons and low operating costs. The other side, they have a few demerits like that they have the relatively high number of moving parts and more discharge pressure ripples. Especially, the discharge pressure ripples bring about vibrations and noises in hydraulic system components such as connecting pipes and control valves, so that these deteriorate the stability and accuracy of the systems. Therefore, the hydraulic systems having the axial piston pumps of bent axis require the methods to reduce the discharge pressure ripples. So, the purpose of this paper is to reduce the discharge pressure ripples by the phase interference of pressure wave and to develope the analysis model of the pumps to predict the discharge pressure ripples. In this paper, the analysis model of the axial piston pumps of bent axis was developed using the AMESim software, and the reliability of that was verified by the comparison with the experimental results. The hydraulic pipeline with a parallel line was used as the method to generate the phase interference of pressure wave. the dynamics characteristics of the hydraulic pipeline with a parallel line were analyzed by a transfer matrix method. the usefulness of the phase interference of pressure wave was investigated through the experiment and simulation. The results from the experiment and simulation said that the phase interference of pressure wave by the hydraulic pipeline with a paralle linel could reduce the discharge pressure wave of the pump well. The analysis model of the axial piston pumps of bent axis developed in this paper and the method of the phase interference by the hydraulic pipeline with a parallel line are expected to be helpful to achieve the design of the pump and to reduce the discharge pressure wave of the pump effectively.

  • PDF

소프트웨어 복제도 감정기법의 표준화 모델에 관한 연구 (A Study on the Research Model for the Standardization of Software-Similarity-Appraisal Techniques)

  • 방효근;차태원;정태명
    • 정보처리학회논문지D
    • /
    • 제13D권6호
    • /
    • pp.823-832
    • /
    • 2006
  • 소프트웨어(SW) 복제도 감정의 목적은 두 프로그램 사이의 동일 또는 유사성 정도를 판단하는 것으로, 컴퓨터프로그림 저작권 관련 분쟁해결의 주요한 기술적 판단근거를 제시하는 제도라 할 수 있다. SW감정을 진행함에 있어서 중요한 점은 감정인의 주관적 판단에 편중되지 않도록 하고, 신속 객관적인 감정의 수행으로 정확한 감정결과를 도출해내는 것이다. 그러나 현재까지 체계적인 감정기법의 표준화 연구 및 개발은 미비한 상태이며, SW감정 분야별(유형별) 감정기법 조차 전문 감정인들에 따라 그 접근방법이 천차만별이어서 뚜렷한 표준안이 제시되지 못하고 있다. 또한, 기 수행되었던 감정사례에 대한 실증적 분석 결과, 기존 감정 절차 및 기법의 오류 또는 감정인의 전문지식 결여 등의 문제가 잠재하여 일부 감정결과에 대한 객관성 및 정확성에 손상이 있음을 알 수 있다. 본 논문에서는 감정인에 따라 동일한 평가 항목에 대하여 서로 다른 결과가 도출될 수 있는 오차의 허용치를 감소시키기 위한 객관적인 평가 방법과 정형화된 SW복제도 감정기법의 표준화 모델을 제시한다. 특히, 기존 감정기법의 문제점 해결 및 보완 연구를 기반으로 감정범위의 설정, 감정기준 및 방법, 단위작업 프로세스 기준의 감정영역 및 감정항목 설정, 가중치 부여, 논리적 복제도와 물리적 복제도 산출 등에 초점을 맞추어 감정기법을 분석 평가한다. 따라서 SW복제도 감정 기법의 표준화 모델은 감정인의 주관적 판단에 의한 오류의 가능성을 최소화하고, 감정결과의 객관성 및 신뢰성을 한층 제고하기 위한 도구를 제공할 것이다.

사회기반시설의 화산재해 복구 우선순위 산정 (Priority Analysis for Infrastructure Recovery from Volcanic Disaster)

  • 박형근;강교석
    • 대한토목학회논문집
    • /
    • 제34권3호
    • /
    • pp.989-998
    • /
    • 2014
  • 최근 아이슬란드의 에야프얄라요쿨화산과 인도네시아의 메라피화산의 등 대형화산재해에 따른 국가적 손실이 세계 곳곳에서 빈번하게 발생하고 있으며 천문학적인 경제적 손실과 인명손실이 발생하였다. 국내의 경우 한반도의 백두산이 최근 빈번한 지진파가 발생하는 가운데 백두산화산 분화의 가능성이 고조되고 있는 현실이다. 본 논문은 사회기반시설에 대해 18가지로 분류를 통해 인도네시아 현지 공무원, 주민, 연구원을 대상으로 사회기반시설의 복구우선순위에 대한 리커트 5점척도 방법으로설문을 실시하여 설문결과에 가중치를 적용, 정량적인 복구우선순위 결과와 사회기반시설의 복구 니즈를 도출하였다. 국내의 경우 화산재해의 피해경험이 전무하기 때문에 이에 따른 피해자들의 복구수요파악이 부족한 실정이다. 따라서 본 연구를 통해 도출된 재해 복구 우선순위를 국내 대형 화산재해 발생 시 복구 우선순위로 활용할 수 있을 것으로 기대하며 연구결과를 활용하여 화산재해 발생 시 복구, 복원 시 참고할 수 있는 자료로써 활용될 수 있을 것으로 기대한다.

미래 보건치과위생사에게 기대하는 인성과 그 진출전망에 대한 전국 보건치과위생사 대표단의 심층면담 (In-depth interview about expected role and competency of future public health dental hygienist)

  • 김솔;김수정;장미래;김민경;서양경;이희연;장영은;박귀옥;김남희
    • 한국치위생학회지
    • /
    • 제16권6호
    • /
    • pp.969-978
    • /
    • 2016
  • Objectives: The purpose of the study was to examine the expected role and competency of future public health dental hygienist. Methods: This study was cross-sectional design. One dental hygienist per 16 cities and provinces was selected from the list of Korea Society of public dental hygienists. After signing in the informed consent, the interview was carried out. Transcripts were made after each interview. Six researchers recorded meaningful contents in the transcripts. They classified and integrated the information that they had recorded commonly or not. Their opinions were converged by conference. Two supervisors verified results whether they were derived from actual recordings for the reliability of the results. The records were confirmed once again and corrected into common message. Results: The main difficult subjects in public health official examination were public health, English, and medical legislation to pass the examine. The preliminary certificates included public health related certificate, computer certificate, and driver's license. In the personality aspect, creativity, activeness, cooperation and good responsibility were very important trait to public health official. Among 16 interviews, 9 were positive and 5 were negative about the future prospects of a public dental hygienist. Conclusions: The future of public health dental hygienist will be positive. Throughout effort to prepare for the public health official, the public health dental hygienist will be expanded and in many ways the dental hygienists will take the charge of the important parts of the public health administration in the near future.

경쟁적 환경이 e-Biz통합의 결정요인 구성과 경영성과에 미치는 영향 (The Impact of Competitive Environments on the Configuration of e-Biz Integration Determinants and the Business Performance)

  • 한봉호;김철수;서창수
    • Asia pacific journal of information systems
    • /
    • 제21권2호
    • /
    • pp.59-87
    • /
    • 2011
  • These days, firms are focusing on the improvement of relationships with business partners. The supply chain integrations are taking critical role in improving the relationships with business partners. In accordance with the development of the IT technology, it became possible for firms not only to integrate inner parts of the organization, but also to integrate the company with other organizations in the supply chain. Therefore, in e-Biz environments, it is imperative for firms to strengthen the core capacity through the supply chain, and to precisely determine the components of the determinants of e-Business integration which impact the firm performance. This study analyzed determinants that have impacts on e-business integration in e-business capacity perspectives in competitive environments. This study based on the premise that the resources and capacities that Grant(1991) and Hart(1995) emphasized do not directly influence the corporate performance. This study focused on the fact that corporate must create core competencies based on these capacities to establish competitive edge. Therefore, this study model analyzed to find out which e-Biz competencies are needed to integrate e-Biz according to competitive environment elements. This study designed to empirically analyze the impact of the e-Biz competencies to the e-Biz integration and to the corporate performance. Independent variables of this study-IT management, partner management, e-Biz knowledge, e-Biz establishment and proliferation, process innovation-are selected based on precedent studies on e-Biz competencies. We selected intermediate variables to verify that e-Biz competencies do not have direct impact on the corporate performance, but have impact on the e-Biz integration, which is intermediate effect. That is to verify that if the components of supply chain improve the integration level using e-Biz competencies, the overall supply chain performances will improve. Dependent variables are selected to verify that e-Biz integration has impacts on corporate performances. This study used factor analysis, path analysis, moderating effect analysis as statistical tests. First, we used exploratory factor analysis and confirmatory factor analysis to analyze reliability and validity. Because e-Biz competencies are presented variously by preceding studies, we used SPSS16.0 to verify if survey questionnaire used by theoretical backgrounds is properly composed. Second, we tested the property of structure model by AMOS. We did path analysis using AMOS16.0 to test structure that is composed of e-Biz competencies and e-Biz integration. Last, we tested moderating effects of measure factors. We analyzed 163 domestic companies to find out many significant suggestive points. First, relationship improvement capacity, e-business knowledge sharing capacity with business partners, and process innovation capacity are adopted as determinants of differentiation and competitive edges against competing firms. Second, e-business knowledge sharing capacity, and process innovation capacity are analyzed as the determinants of e-business integration in the firm which demand fluctuation in the market is high. On the other hand, among the determinants that require capturing ideas on new products, and strengthening the technological power, process innovation capacity are adopted as the determinants. These results provide us the foundation that the determinants that we have analyzed can impact the supply chain integration strategies which take into account the competitive environments.

탄도 수정탄 롤제어시스템 충격해석 모델 개발에 관한 연구 (A Study on the Development of Impact Analysis Model of Roll Control System for Course Correction Munition)

  • 고준복;윤찬식;김용대;김완주;조승환
    • 대한기계학회논문집A
    • /
    • 제39권8호
    • /
    • pp.737-742
    • /
    • 2015
  • 탄도 수정탄은 기존의 포탄에 조종 kit를 장착하여 목표를 정밀 타격할 수 있게 하는 무기 체계이다. 롤제어시스템은 조종 kit의 구성품으로 유도조종부와 탄체부 사이에 위치하며 포발사시 횡방향으로 5,000g 상당의 가속도 하중을 받게 된다. 따라서 내고충격 설계를 하는게 중요하다. 선진국에서는 탄도 수정탄의 개발과정에서 실사격 또는 포발사 회수 시스템을 이용하여 부품의 성능 및 강도를 평가하고 있으나 많은 시간과 비용이 든다는 단점이 있다. 따라서 본 연구에서는 CAE 해석적 방법으로 설계단계에서 롤제어시스템에 대한 충격 강도 평가를 할 수 있도록 해석 모델을 개발하였다. 충격 현상을 구현하기 위하여 Explicit code를 이용한 Dynamic 해석 기법을 적용하였고, 고변형률 물성 특성을 Johnson-Cook material model을 이용하여 구현하였다. 또한 베어링을 인너, 아우터 레이스, 리테이너, 볼 등으로 상세적으로 구현하여 충격시 베어링의 거동 특성이 분석될 수 있도록 하였다. 개발된 해석 모델은 가스건 충격시험을 통해 그 신뢰성이 있음을 검증하였다.

전동 조향 장치용 브러쉬리스 영구자석 전동기의 스테이터 스큐 설계 (Design of Brushless Permanent Machine with Skewed Stator for Electrical Power Steering System)

  • 이충성;정경태;홍정표;김해중;김영균
    • 한국자기학회지
    • /
    • 제25권6호
    • /
    • pp.189-197
    • /
    • 2015
  • 최근 차량의 연비규제 강화로 인해, 기존 내연기관의 차량 부품 구동방식이 유압방식 대신 전동방식으로 대체되어 가고 있다. 이러한 부품의 대표적인 예가, Electronic Power Steering(EPS)이며, 현재 대부분의 차량에 적용되고 있다. EPS의 핵심 부품으로서는 전동기가 있으며, EPS의 조향감 개선 및 진동/소음 저감을 위해 전동기의 Cogging torque 및 Torque Ripple 저감이 요구된다. 일반적으로 Cogging torque 및 Torque ripple을 저감하기 위해서, 고정자 또는 회전자에 스큐를 적용한다. 본 연구에서는 고정자에 스큐가 적용된 Bushless PMSM(Permanent Magnet Synchronous Motor)의 설계 방법 및 해석방법에 대해 소개한다. 고정자 skew가 적용된 EPS용 PMSM에 대해 초기 설계를 진행하고, RSM(Response Surface Methodology)을 이용한 최적설계를 수행한다. 유한요소해석을 통해 역기전력, Inductance, Load torque 등의 성능을 확인한다. 마지막으로 시제품 제작 및 실험을 통해 설계 방법에 대한 신뢰성을 검증한다.

저전력 무선 센서 네트워크를 위한 RS 코드의 성능 분석 (Performance Analysis of RS codes for Low Power Wireless Sensor Networks)

  • 정경권;최우승
    • 한국컴퓨터정보학회논문지
    • /
    • 제15권4호
    • /
    • pp.83-90
    • /
    • 2010
  • 무선센서네트워크에서는센서노드로부터전송된데이터는채널의노이즈등의요인으로 오류가 일어나기 쉽다. 센서 네트워크는 엄격한 에너지 제안이 있기 때문에 에너지가 효율적인 오류 정정 방법을 사용하는 것이 중요하다. 본 논문에서는 낮은 전송 전력으로 전송한 데이터를 RS 코드를 적용하는 방식을 제안하고, 시뮬레이션과 실험을 수행한다. RS 코드는 데이터에 추가한 리던던시로 동작한다. 인코드 데이터는 저장되거나 전송될 수 있다. 오류가 발생했을 때 인코드된 데이터는 복원된다. 추가된 리던던시는 디코더에서 수신된 데이터에서 오류가 있는 부분을 감지하고 정정하는 데에 사용된다. RS 코드가 정정할 수 있는 오류의 수는 추가되는 리던던시에 의해 결정된다. 실험 결과 저전력 통신에서의 높은 안정성을 확인하였다. 1분마다 32바이트를 전송할 경우 RS(15,13)은 173.7일, RS(31,27)은 169.1일, RS(63,57)은 163.9일, RS(127,115)는 150.7일, RS(255,239)는 149.7일의 수명을 예측할 수 있었다. 패킷 수신 확률(PRR) 실험에 RS(255,239)를 적용하여 약 3m 전송거리가 증가함을 확인하였다.