• 대한수학회보
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• 제49권2호
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• pp.307-317
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• 2012

We say (W, {${\phi}_1,\;{\ldots}\;,{\phi}_t$}) is a polarizable dynamical system of several morphisms if ${\phi}_i$ are endomorphisms on a projective variety W such that ${\otimes}{\phi}_i^*L$ is linearly equivalent to $L^{{\otimes}q}$ for some ample line bundle L on W and for some q > t. If q is a rational number, then we have the equidistribution of small points of given dynamical system because of Yuan's work [13]. As its application, we can build a polarizable dynamical system of an automorphism and its inverse on a K3 surface and can show that its periodic points are equidistributed.

• Ocean Systems Engineering
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• 제3권3호
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• pp.181-201
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• 2013

The main objective of this work is to investigate the sloshing behavior in a baffled and unbaffled three dimensional annular-sectored water pool (i.e., tank) which is located at dome region of the primary containment. Initially two case studies were performed for validation. In these case studies, the theoretical and experimental results were compared with numerical results and good agreement was found. After the validation of present numerical procedure, an annular-sectored water pool has been taken for numerical investigation. One sector is taken for analysis from the eight sectored water pool. The free surface is captured by Volume of Fluid (VOF) technique and the fluid portion is solved by finite volume method while the structure portions are solved by finite element approach. Baffled and un-baffled cases were compared to show the reduction in wave height under excitation. The complex mechanical interaction between the fluid and pool wall deformation is simulated using a partitioned strong fluid-structure coupling.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1778-1783
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• 2000

When visual intrusion is an important factor, it is desirable to find alternative methods of improving the insertion loss of a noise barrier without increasing the height. Therefore, the primary object of the work attenuates the noise due to transport vehicle by small interference device installed at noise barrier edge. In this paper the performance of noise barriers with attached interference device, in terms of shape, absorptive material and split panel, are examined using the boundary element approach. Also, the scale models are moanted in an anechoic chamber and the frequency of the sound sources are appropriately scaled to simulate full scale site conditions. Lastly, experimental measurements of the designs are executed for a range of frequencies and receiver positions, and are compared with the results of numerical modeling.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.522-525
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• 2007

기존의 로봇과 2족 로봇의 가장 큰 차이점은 이동시 바퀴를 사용하지 않고 두 다리를 사용한다는 것이다. 상식적으로 생각해 보면 이동성과 안정성 면에서 바퀴는 다리보다 훨씬 효율적이다. 그럼에도 불구하고 2족 로봇은 수많은 역할을 해낼 수 있다. 그러나 두 다리로 중심을 잡고 안정적으로 걷는다는 것은 쉬운일이 아니다. 그래서 본 논문에서 2족 로봇의 보행을 위한 기술적 요소를 중심으로 시스템을 설계하고 구현에 대해 논의하고자 한다.

• Steel and Composite Structures
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• 제13권3호
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• pp.225-238
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• 2012

Steel structural elements with web-tapered I cross section, are usually made of welded thin plates. Due to the nonrectangular shape of the element, thin web section may be obtained at the maximum cross section height. The buckling strength is directly influenced by lateral restraining, end support and initial imperfections. If no lateral restraints, or when they are not effective enough, the global behaviour of the members is characterized by the lateral torsional mode and interaction with sectional buckling modes may occur. Actual design codes do not provide a practical design approach for this kind of elements. The paper summarizes an experimental study performed by the authors on a relevant number of elements of this type. The purpose of the work was to evaluate the actual behaviour of the web tapered beam-columns when applying different types of lateral restraints and different web thickness.

• 대한안전경영과학회지
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• 제9권2호
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• pp.59-69
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• 2007

The main objective of this study is to suggest the new sizing system proper to the boys in the high school students by classifying their somatotype for the development of educational environment and uniform. The sample for this work was chosen from data which were collected and measured by Size Korea during two years $(2003\sim2004)$. In order to analyze feature of the somatotype of boys in the high school students, analysis was performed about 479 subjects on 37 body parts such as height (9 parts), width (5 parts), thickness (6 parts), circumference (7 parts), length (8 parts), body weight and $R\ddot{o}hrer$ Index. The result of this study can be utilized in various fields such as design of classroom, student uniforms, facilities and equipments for education at high school and university, etc.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.537-542
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• 2000

When visual intrusion Is an Important factor, it is desirable to find alternative methods of Improving the insertion loss of a noise barrier without Increasing the height. Therefore, the primary object of the work attenuate the noise due to railway by small interference device installed at noise barrier edge. In this paper the performance of noise barriers with attached interference device, in terms of shape, absorptive material and split panel, we examined using the boundary element approach. Also, the scale models are mounted in an anechoic chamber and the frequency of the sound sources are appropriately scaled to simulate full scale site conditions. Lastly, experimental measurements of the designs are executed for a range of frequencies and receiver positions, and are compared with the results of numerical modeling.

• 동력기계공학회지
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• 제10권4호
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• pp.38-42
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• 2006

Pressure drops and friction factors in square channels with twisted tape inserts plus axial interrupted ribs are investigated. Tests are performed for Reynolds numbers ranging from 8,900 to 29,000. The rib height-to-channel hydraulic diameter, $e/D_h$, is kept at 0.057 and test section length-to-hydraulic diameter, $L/D_h$ is 30. The pressure drops and friction factor values are enhanced with axial interrupted ribs and twisted tape inserts. Square channels with twisted tape inserts plus axial interrupted ribs show the greatest pressure loss penalty in the present work. Friction factor data obtained for the square channel with twisted tape inserts plus axial interrupted ribs are less than those in the past publications for circular tubes with axial interrupted ribs and twisted tape inserts.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1060-1067
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• 2009

The selection and operation of tower cranes at construction sites are dependent on the personal experience of engineers in charge of lifting work. It often causes to overestimate the safety factor resulting in increase of construction cost, or underestimate it resulting in disastrous accident. Therefore, selection of tower cranes needs to consider cost, safety and maximum lifting condition. This study, for resolving such problems, was intended to propose the algorithm designed for even the inexperienced person to select the optimal lifting equipment in timely manner. The algorithm presented herein is an optimization algorithm that enables automatic arrangement of tower crane and minimization of costs by analyzing such conditions as vertical height and lifting load, etc.

• Safety and Health at Work
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• 제3권2호
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• pp.146-153
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• 2012

Objectives: The introduction of computerized numeric control (CNC) technology in manufacturing industries has revolutionized the production process, but there are some health and safety problems associated with these machines. The present study aimed to investigate the extent of postural discomfort in CNC machine operators, and the relationship of this discomfort to the display and control panel height, with a view to validate the anthropometric recommendation for the location of the display and control panel in CNC machines. Methods: The postural discomforts associated with CNC machines were studied in 122 male operators using Corlett and Bishop's body part discomfort mapping, subject information, and discomfort level at various time intervals from starting to end of a shift. This information was collected using a questionnaire. Statistical analysis was carried out using ANOVA. Results: Neck discomfort due to the positioning of the machine displays, and shoulder and arm discomfort due to the positioning of controls were identified as common health issues in the operators of these machines. The study revealed that 45.9% of machine operators reported discomfort in the lower back, 41.8% in the neck, 22.1% in the upper-back, 53.3% in the shoulder and arm, and 21.3% of the operators reported discomfort in the leg. Conclusion: Discomfort increased with the progress of the day and was highest at the end of a shift; subject age had no effect on patient tendency to experience discomfort levels.