Earticle

본 연구의 목적은 산업설비나 건축설비의 배관에서 불순물 유입을 막아 유동 시스템을 보호할 수 있는 스 트레이너를 개발하기 위함에 있다. 스트레이너는 청수 또는 기름, 가스가 유입되는 배관라인의 밸브, 기기, 펌프 전 단에 설치되는 장치로 형태에 따라 Y형, U형, T형이 있다. 본 연구에서는 Y형 스트레이너의 문제점을 파악하고 그 보다 개선된 새로운 모델 “유입․유출구가 일직선상에 있는 C형 스트레이너”를 개발하여 실물 시험을 통해 그 성능을 비교하였다. 시험은 기존 Y형과 C형 스트레이너 50A 실물을 한국표준과학연구원(KRISS) 유동실험실에서 4가지 상 황별 실물시험으로 유동특성을 고찰하였다. 실험결과 C형 스트레이너가 Y형 보다 여과망이 없을 때는 74.9%, 여과 망에 불순물이 없을 때는 54.5%, 불순물이 15% 쌓였을 때는 54.2%, 불순물이 30% 쌓였을 때는 52.4%가 용량계수 (Kv)값이 높았다. 실물제작의 한계로 50A 한 종류만 시험했지만 결과로 볼 때 Y형보다 C형 스트레이너가 유동특성 이 우수한 것으로 입증되어 향후 건축, 산업현장에서 유용하게 사용될 것으로 판단되었다.

The purpose of this study was to develop a strainer that could protect a flow system by blocking the introduction of foreign substances into the pipe of industrial or architectural facilities. Strainers are installed at the front tip of valves, machines, or pumps in the piping line of clean water, oil, or gas. There are Y-type, U-type, and T-type strainers. The study identified problems with the Y-type strainers, develop a "C-type strainer with its inlet and outlet on a straight line" as a more improved new model, and compared them in functions in a full-scale strainer test. The study conducted a full-scale strainer test according to four situations at the flow laboratory of Korea Research Institute of Standards and Science by using the old Y-type strainer and C-type strainer 50A. The test results show that the C-type strainer had a higher capacity coefficient(Kv) than the Y-type one, recording 74.9% when there was no screen, 54.5% when there were no foreign substances in the screen, 54.2% when there was a 15% accumulation of foreign substances, and 52.4% when there was a 30% accumulation of foreign substances. The investigator conducted a test only with the 50A type due to the limitations of life-size strainers, but the results demonstrate that the C-type strainer had better flow characteristics than the Y-type one.

Objective To evaluate the association between baseline characteristics, three physical performance tests and fall history in a sample of the elderly from Korean population.Methods A total of 307 participants (mean age, 76.70±4.85 years) were categorized into one of two groups, i.e., fallers and non-fallers. Fifty-two participants who had reported falling unexpectedly at least once in the previous 12 months were assigned to the fallers group. Physical performance tests included Short Physical Performance Battery (SPPB), Berg Balance Scale (BBS), Timed Up and Go test. The differences between the two study groups were compared and we analyzed the correlations between fall histories and physical performance tests.Results SPPB demonstrated a significant association with fall history. Although the BBS total scores did not show statistical significance, two dynamic balance test items of BBS (B12 and B13) showed a significant association among fallers.Conclusion This study suggests that SPPB and two dynamic balance test items of the BBS can be used in screening for risk of falls in an ambulatory elderly population.

The purpose of the present study was to investigate whether there is a relationship between the outcome of preseason physical performance tests and the risk of sustaining lower extremity muscle injuries within the same season, in male football players at elite level. This is a cohort study of a male football team (63 players) from the first league in Swe-den. The football players are prospectively followed, in terms of muscle injuries of the lower extremity during five seasons between 2010 and 2014. All muscle injuries were evaluated and diagnosed with ultraso-nography. The following physical performance tests were included: squats, chin-ups, YoYo intermittent recovery level 2, counter movement jump, squat jump, standing long jump, sprint, one leg squat test, and a functional movement screen. A total of 86 muscle injuries occurred during the study period. No significant correlation was found between the results of the physical performance tests and muscle injuries of the lower extremity. None of the evaluated tests predicted the risk of sus-taining muscle injuries of the lower extremity. We conclude that muscle injury risk factors are more complex than solely related to the results of the preseason physical performance tests.

The aims of this work were to compare the performances of male and female cadet and junior judo athletes and to develop classificatory ta-bles to these judo-specific tests for international-level from these ages. Data collected during training camps of male and female cadet and ju-nior judo teams from three nations (Brazil, Serbia, and Spain) were ana-lyzed, totalizing 252 individual results of special judo fitness test (SJFT), and 222 and 208 of dynamic and isometric judogi chin-up tests, respec-tively. Juniors performed better than cadets in the SJFT, with higher number of throws in A, B, C, and total (P<0.001 for all comparisons), lower final heart rate (P=0.021), and lower index (P<0.001), as well as higher relative performance in the dynamic chin-up test (P<0.001). Fur-thermore, male athletes presented better performance compared to fe-male athletes in the SJFT (higher number of throws in A, B and total, and lower index) and in the isometric and dynamic chin-up tests (higher absolute and relative performances) (P<0.001 for all comparisons). Considering these differences, tables were established by sex and age groups, using percentile values. Thereby, each of the parameters of the SJFT (number of throws, heart rate after and 1 min after the test, and SJFT index), as well as absolute and relative results in chin-up judogi tests, were classified by sex and age. These classificatory tables can be useful for judo coaches to monitor specific physical performance during different phases of periodization process.

This study presents the comparative filtration performance evaluation of automotive fuel filters based on the theory of Beta ratio. For the experiments, the fuel component's test stand incorporating the multi-pass filtration test circuit was developed. A mathematical description of filtration process in general was derived. And the theoretical basis of multi-pass test and the test procedure were described in detail. Experimental results revealed that domestic fuel filter tested could not maintain consistent Beta ratio, that is filtration efficiency, although it had the holding capacity of contaminants close to the specification at maximum pressure drop across the filter assembly. The results of experiments and simulations also showed that filtration system model could be refined including desorption ratio to estimate the variable Beta ratio in service life.

조직에서 우수 인재 확보하려면 선발 도구의 예측 타당도가 높아야 한다. 본 연구는 실제 직무 상황을 반영한 업무 시뮬레이션 과제 수행을 준거로, 논술형 상황판단검사(Situation Judgment Task: SJT)와 구성형 및 선다형 직무적성검사의 상대적 예측력을 비교하였다. 이를 위해 분석적 사고력, 의사소통능력, 문제해결능력을 평가하도록 설계된 네 가지 시뮬레이션 과제를 개발하였다. 대학교 재학생 및 졸업생 50명을 대상으로 논술형 SJT, 직무적성검사, 그리고 개발된 시뮬레이션 과제를 수행하도록 하고, 업무 시뮬레이션 과제 수행 점수를 종속변수로 설정하여 SJT 점수와 직무적성검사 점수를 독립변수로 회귀분석을 수행하였다. 이와 함께, 참여자 간 상호평가를 통해 채점한 SJT 결과와 전문가 평정 결과 간의 일치도를 통해 상호평가 채점 방식의 준거타당도를 검토하였다. 그 결과, 논술형 SJT 점수는 의사소통 능력과 문제해결 능력 과제 수행을 유의미하게 예측한 반면, 직무적성검사 점수의 예측력은 모든 영역에서 미미한 것으로 나타났다. 또한, 상호평가를 기반으로 한 채점 결과와 전문가 평정 간에는 유의미하게 높은 상관이 관찰되었다. 이상의 결과가 갖는 이론적, 실무적 함의와 후속 연구 방향에 대해 논의하였다.

The use of valid selection tools is critical for identifying high-potential talent and ensuring effective organizational hiring decisions. This study empirically investigates the predictive validity of a constructed situational judgment test (SJT) relative to a general aptitude test using work simulation tasks designed to reflect actual job demands. Four simulation tasks were specifically developed to assess analytical thinking, communication skills, and problem-solving abilities. Fifty university students completed both the constructed SJT and a standardized general aptitude test. Regression analyses were conducted using their performance on the simulation tasks as dependent variables. Results indicated that the writing-based SJT significantly predicted performance in communication and problem-solving simulation tasks, whereas the general aptitude test showed insignificant predictive validity across these domains. Additionally, peer-assessed SJT scores correlated strongly with expert ratings, further supporting the criterion validity of peer evaluations within the SJT context. These findings underscore the promise of writing-based assessments, particularly those utilizing peer evaluation, as effective tools for assessing cognitive skills in selection settings. This study contributes to the literature advocating for cognitively demanding assessment formats and offers practical insights into developing cost-effective, scalable hiring systems.

최근 응용 프로그램은 대다수가 웹기반 시스템으로 구현되고 있다. 그것은 정보의 호환 관점에서 웹 기반 정보통합이 사실상의 유일한 대안이 되고 있기 때문이며. 이러한 비즈니스 시장에서 살아남기 위해 기업들이 배포 및 유지보수가 쉬운 웹응용프로그램을 선호했기 때문이다. 문제는 다양한 고객의 요구조건을 웹 응용 프로그램이 충족시키기에는 한계가 있다는 점이다. 이런 문제를 해결하고자 많은 기업은 앞 다투어서 새로운 인터넷 구조인X-Internet기반의 응용프로그램을 출시하고 있으며 기업들도 도입을 서두르고 있다. 본 논문에서는 Internet 시스템을 소개하고 그에 기반을 둔 응용프로그램과 일반적 웹응용프로그램의 성능을 TPC-H 벤치마크 관점에서 비교 분석함으로써 X-Internet 구조의 기본 시스템구조 대비 그 가능성이 크다는 것을 입증하였다.

Application programs recently have been implemented in terms of web based systems. It mainly comes from the reason that the web based system integration is the only alternative of which vendors prefers the systems that they can easily distributed and maintained to the conventional client server systems. The web based systems, however, have their intrinsic limitations to cope with various user requirements. In order to solve these issues, many organizations and companies try to adopt X-Internet based application systems. In this paper, we introduce an X-Internet based system architecture by which it is outperformed in comparing the performance to the general web based systems in terms of TPC-H benchmark test.

이 연구는 저강도 경량기포콘크리트에 대한 구조성능실험 및 평가이다. 경량기포콘크리트는 저강도이기 때문에 다양한 하중에 대하여 영향을 크게 받는다. 본 연구에서는 그 중 경량기포콘크리트에 사용되는 매입 L-앵커의 인발하중이 작용하였을 때의 파괴 모드와 그에 대한 이론적 평가를 비교분석 하였다. 그리고 이러한 연구를 통하여 경량기포콘크리트를 커튼월에 적용하는데 도움을 주고자 한다.

This study is on the structural performance tests and assessment for low strength Autoclaved Lightweight Concrete. Due to its low strength, Autoclaved Lightweight Concrete is greatly affected by various loadings. This study has especially done comparative analysis on Failure Modes under the pullout load of L-anchor used in the Autoclaved Lightweight Concreteand theoretical assessment on that mode so that this can contribute to improvements in the application of Autoclaved Lightweight Concrete to the curtain wall.

The Cold Neutron Research Facility(CNRF) is being built to produce a cold neutron which has peculiar physical property. In-Pool Assembly(IPA) was manufactured in a domestic factory, which is composed of moderator cell, heat exchanger, vacuum chamber, joint flange assembly and bracket etc. We had difficulties with the mechanical fabrication process due to the thin moderator cell. The special flange for the double flexible piping was developed. The tests of moderator cell, heat exchanger, vacuum chamber, double flexible pipe and IPA include the pressure test, normal temperature leak test and low temperature leak test. The moderator cell and heat exchanger were tested in the severe environmental condition and the burst tests of moderator cell were carried out. Above all, the bursting point took place at the area of the 0.01mm thinner place. It shows that the severe environmental test affects the bursting strength. The double flexible pipe welding at the IPA top plate was related with the arrangement of moderator cell in the vacuum chamber. Therefore the connecting welding of the double flexible pipe linked to sequent of the vacuum piping, helium piping and hydrogen piping. The fabrication, test and assembling of cryogenic in radiation zone were developed.

최근 급속한 도시화 및 1인 가구의 증가 등으로 인하여 강력범죄(살인, 강도, 강간 등)로 이어질 가능성이 높은 침입범죄가 지속적으로 증가하고 있다. 또한, 경찰관 증원, 방범용 CCTV 증설 등 치안 분야의 투자가 확대되면서 범죄 검거율 상승에도 불구하고 국민이 피부로 느끼는 우리사회의 안전 수준은 상대적으로 미흡한 것으로 나타났다. 따라서 범죄예방을 위해 무질서한 환경을 정비하고 물리적 방어공간을 형 성하여 지역사회 범죄의 위험을 관리하고자 범죄예방대책으로 CPTED(Crime Prevention Through Environmental Design, 범죄예방환경설계)가 물리보안과 범죄예 방의 대안으로 부각되었다. 물리적 보안의 효과를 극대화하기 위해서는 이러한 CPTED의 전략 중 대상물 강 화 방법인 타겟하드닝(Target Hardening)이 중요하다. 이는 대상 건축물 등에의 침입 을 어렵게 하여 범인이 범행을 스스로 포기하도록 유도하는 기법으로 침입범죄를 직접 차단하기 때문에 CCTV 또는 센서와 같은 보안장치보다 더 직접적이고 실효적 인 것으로 나타났다. 타겟하드닝 전략의 일환으로 외국의 경우 실질적인 침입방지성 능을 갖춘 제품인지 확인하기 위해 창, 문 등 방범하드웨어에는 시험원이 도구를 가지고 하는 시험방법인 ｢시험원에 의한 시험방법｣을 활용하는 것이 일반적인 기준이지만, 국내의 경우 시험원이 도구를 가지고 시험하는 시험방법이 정량적이지 못해 신뢰성이 떨어진다는 이유로 도입되지 못하는 현실이다. 이러한 배경에 따라 본 연 구는 타겟하드닝 전략을 실현시킬 현실적 방법인 ｢시험원에 의한 시험방법｣의 타당 성 분석을 통한 신뢰성 검증을 진행하였다. “시험원간 숙련도 시험 결과 값은 차이가 없을 것이다.” 라는 가설을 검증하기 위하여 주요 침입구 중에서 특히 방범문의 침입 저항 시험을 진행하였다.

Recent social-economic developments have accelerated urbanization and the number of one-person households, raising public security issues along with it. Burglaries that have a high probability of leading to violent crimes(murder, robbery, rape, etc.) are continuously increasing as well. Although the crime arrest rates have been increasing due to investments in public security areas such as more police officers and on-street CCTVs, the safety level people feel within the society is still insufficient. To prevent these crimes, major nations such as England, USA, Japan have been emphasizing CPTED(Crime Prevention Through Environmental Design) to create a defensive space for crimes and modify the disordered environment, changing the crime response paradigm to prevention instead of post-action. To maximize the effect of CPTED, ‘Target Hardening’ is an effective method hardening buildings, facilities, or environments. This makes burglary crimes difficult and induct the criminals to give up on committing a crime. This method proves to be better in blocking house break-ins directly compared to indirect methods using CCTVs and intrusion sensors as a security device. A part of ‘Target Hardening’ strategy is to review whether a product is burglary attack-resistant. The general method is to test burglary-resistant hardware such as windows and doors with the test method ‘manual burglary-resistance test by a human tester’. However, it has failed to apply domestically due to the lack of quantitative test method and reliable results. According to these backgrounds, this thesis looks to focus on one of the CPTED strategies ‘Natural Access Control’ to undergo a feasibility analysis for ‘Burglary resistance test’ in order to realistically fulfill the ‘Target Hardening’ strategy. In order to verify the hypothesis “There will be no difference in test results between different testers”, burgalry resistance tests were executed and results went through a equal variance test according to the Cochran formula. Afterwards, Grubb’s test was used to review whether the significance level rejection rate surpassed 5%, and one-on-one analysis of variance was done to see if F ratio was below F critical value to verify the hypothesis.

근래에 들어 기존의 PSC 거더 교량 외에 다양한 형태의 교량이 개발되고 있으며, 다단계 긴장에 의한 PSC 거더교는 대표적인 예이다. 다단계 긴장 PSC 거더교는 구조적 개념에 따라 자중을 줄이고 경간을 장대화할 수 있는 장점을 갖고 있다. 그러나, 이와 같은 장대화된 보다 유연한 교량은 구조적 안전성 및 사용성을 고려한 주행열차하중에 대한 동적거동 검토가 필수적이며, 철도교량의 주행열차하중에 대한 동적성능평가를 위한 정확한 동특성 입력은 매우 중요하다. 본 연구에서는 정확한 고유진동수 및 감쇠비 추출을 위하여 25m 실물 다단계 긴장 PSC 거더를 제작하여 시공단계별 모달테스트를 수행하였다. 모달테스트를 위한 가진방법으로 기존의 충격햄머에 의한 방법 외에 디지털 콘트롤에 의한 가진기를 사용하여 보다 정확한 주파수응답 함수를 얻고자 하였다. 또한, 시공단계별 구조계 변화 및 긴장에 의한 동특성 변화를 고찰하기 위하여 시공단계별 실험을 수행하였다. 모달테스트 결과에 의한 동특성 값을 주행열차하중 해석에 적용하여 다양한 매개변수연구를 통한 철도교량 동적성능평가를 수행하였다. 동적처짐, 충격계수, 바닥판의 연직가속도, 단부꺾임각 등에 대하여 열차별, 속도별 동적해석을 수행하여 국내외 철도교량 동적성능 평가기준과 비교하였다.

As an alternative to conventional prestressed concrete (PSC) girders, various types of PSC girders are either under development or have already been applied in bridge structures. Incrementally prestressed concrete girder is one of these newly developed girders. According to the design concept, these new types of PSC girders have the advantages of requiring less self-weight while having the capability of longer spans. However, the dynamic interaction between bridge superstructures and passing trains is one of the critical issues concerning these railway bridges designed with more flexibility. Therefore, it is very important to evaluate modal parameters of newly designed bridges before doing dynamic analyses. In the present paper, a 25 meters long full scale PSC girder was fabricated as a test specimen and modal testing was carried out to evaluate modal parameters including natural frequencies and modal damping ratios at every prestressing stage. During the modal testing, a digitally controlled vibration exciter as well as an impact hammer is applied, in order to obtain precise frequency response functions and the modal parameters are evaluated varying with construction stages. Prestressed force effects on changes of modal parameters are analyzed at every incremental prestressing stage. With the application of reliable properties from modal experiments, estimation of dynamic performances of PSC girder railway bridges can be obtained from various parametric studies on dynamic behavior under the passage of moving train. Dynamic displacements, impact factor, acceleration of the slab, end rotation of the girder, and other important dynamic performance parameters are checked with various speeds of the train.

본 연구는 실제 발전소 내 운영 설비의 고정부에 사용되는 앵커에 대하여 지진 발생 시 안전성을 평가하는 것이 주된 목적이다. 이에 따라 운영 설비와 같은 비 구조적 구성 요소의 고정부 앵커에 실제 지진이 발생하였을 경우 발생되는 하중에 대한 응답을 조사하기 위해 실험적 연구를 수행하였다. 실제 다양한 형태를 갖는 비구조요소를 연구하는 데는 경제적, 공간적 제약이 있기 때문에 프레임과 질량으로 구성된 대체 시험체를 제작하여 진동대 시험을 수행하였다. 고정부 콘크리트 앵커의 동적 특성과 내진성능을 평가하기 위해 진동대 시험을 통해 대상 구조물의 고유 진동수를 파악한 후 실제 지진과 같은 인공 지진 효과를 발생시켜 실험을 수행하였다. 결론적으로 시험체에 볼트를 이용하여 강철 프레임을 고정시켜 구조적 강성을 확보하였으며, 이에 따라 고정부 앵커에 전달되는 하중이 감소되는 것을 확인하였다. 향후 해석적 접근을 통하여 실험에 대한 신뢰성 검증 및 현장 여건 상 수행되지 못한 부분에 대하여 연구를 수행할 예정이다.

The main purpose of this study is to assess the safety of the fixed anchorages subjected to the seismic motion for an operating facilities in the actual power plant. Thus, the experimental study was conducted to investigate the load response in the event of an actual seismic to the anchorages of a nonstructural components. Since there are economic and spatial constraints to study nonstructural components that actually have various forms, alternative test specimens of steel frames with mass were built and the shaking table test was carried out. In order to evaluate the dynamic characteristics and seismic performance, the natural frequency of the target structure was identified through the shaking table test and then the load response characteristics of the anchorage were evaluated by generating an artificial seismic effect like actual seismic. Finally, the structural stiffness was reinforced by fixing the steel frame to the test specimen using bolts, thereby reducing the load transmitted to the anchorage. It will be carried out on the reliability verification of the experiments and areas that have not been carried out due to the site conditions through the analytical approach in the future.

본 연구의 목적은 ITS 업무요령 및 ITS 성능평가 제도 개선을 위한 법․규정의 개정을 제안한다. 본 연구는 ITS 업무요령 및 ITS 성능평가 제도의 현황과 문제점을 분석하고 개선방안을 제시함으로써 신뢰성 있는 교통정보를 제공하고, 제도 개선을 통하여 민원 발생의 우려를 줄이며, 사회적 비용도 감소시키게 된다. 또한, ITS 장비와 센터의 유지관리 기준과 ITS 성능평가 업무의 직무분석을 통한 업무분담 체계화, ITS 성능평가기관의 역할 정립과 기술위원회의 기능을 정립하여 ITS 성능평가 제도 개선 하에서 생산되는 교통 자료의 신뢰성이 높아지고 새로운 차원의 서비스를 도출할 수 있어서 ITS 시스템의 효율성 증대 및 투자 효과의 극대화를 제공할 것이다.

The objective of this study is to revise the related regulations and laws of intelligent transport systems performance tests and methods. This study improves the reliability of present traffic information, reduce public discontent by systematic reforms and reduce national and social costs through the analysis of intelligent transport system performance tests’current status and problems. This study will maximize the investment profits and efficiency of ITS system as the reliability of transportation information which is created through the maintenance of ITS equipment and center, systemization of work responsibility through close analysis of ITS performance test and overall evaluation of role of ITS performance assessment organization will improve and new level of service will be born.

The present study investigated students’ preferences for the types of tasks used to assess English speaking performance. It further examined whether students’ task type preferences affected their perceptions of test effectiveness. One hundred eighty-two high school students responded to a self-report questionnaire. A series of frequency analysis and paired samples t-tests were used for the analysis. The results showed that students’ most preferred task types and their least preferred ones overlapped with each other, suggesting that the task types of English-speaking performance tests used in schools are limited. The four key reasons determining students’ task type preferences were identified, including task difficulty, emotional comfort, practical value, and interest. In addition, the results indicated that students’ task type preferences could affect their perceptions of task effectiveness. Overall, the results suggest the need for developing more varied task types for English-speaking performance tests as well as helping students become familiar with English speaking performance tasks. Pedagogical implications were discussed along with study limitations.

본 연구는 정상 노인과 초기 단계의 노년기 인지 장애(경도인지장애(MCI), 경도 치매)의 선별검사인 대면 이름대 기와 범주 이름대기의 예측력을 파악하였다. 노년기 인지장애로 진단을 받은 340명(정상 노인 203명, MCI 106명, 경 도 치매 31명)을 분석하였다. 대면 이름대기는 단축형 한국판 보스턴 이름대기 검사로 측정하였고, 범주 이름대기는 통제연상단어검사의 의미검사와 음소검사를 이용하여 측정하였다. 이름대기 검사의 예측 성능을 비교하고자 다항 로지 스틱 회귀분석을 수행한 결과, 대면 이름대기와 범주 이름대기 검사 모두 일반노인에서 MCI와 경도 치매를 감별하는 데 유의미한 효과가 확인되었다(p<0.05). 반면, MCI에서 경도 치매를 감별할 때, 범주 이름대기의 음소검사는 교차비가 유의미하지 않았다. 본 연구의 결과는 MCI에서 경도 치매를 감별할 때, 범주 이름대기의 총점만을 측정기준으로 분석하 는 것은 유의하지 않을 가능성이 높음을 시사한다.

The present study identify the predictive power of confrontational naming and generative naming as screening tests for normal and early cognitive impairment. The subjects were analyzed for 203 healthy elderly, 106 mild cognitive impairment (MCI), 31 mild dementia. The confrontational naming was measured by the short-term Korean Boston Name Waiting Test, and the generative naming was measured by the Control Associative Word Test. As a result of polynomial logistic regression, both confrontational naming and generative naming had a significant effect on discriminating cognitive impairment (MCI, mild dementia) in general elderly (p<0.05). On the other hand, when distinguishing mild dementia from mild cognitive impairment, the generative naming-phonetic test had no significant odds ratio. The results of this study suggest that when discriminating mild dementia in mild cognitive impairment group, it is not meaningful to look only at the total score of generative naming test.