• Design & Manufacturing
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• 제11권3호
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• pp.29-34
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• 2017

Increased demand for parts with micro-pattern structure made of metals, ceramics, and composites in various fields such as medical ultrasonic sensors, CT collimators, and ultra-small actuator parts. Micro powder injection molding (PIM) is a technology for manufacturing micro size, high volume, complex, precision, net-shape components from either metal or ceramic powder. In the present study, a standard mold with a variable insert core capable of producing various micro patterns was investigated. An injection molding test was performed on a standard mold using a line type micro-pattern core having an aspect ratio of 2, a slenderness ratio of 70, a pattern size of $200{\mu}m$, and a pattern spacing of $150{\mu}m$. During the filling process, the deformation of the mold with large aspect ratio and slenderness ratio was analyzed by the experiment and the numerical simulation according to the position of the gate. We proposed a mold structure that minimizes mold deformation by gate modification and enables uniform pattern filling behavior.

• 한국산학기술학회논문지
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• 제15권7호
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• pp.4100-4104
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• 2014

대중음악산업에서 이용매체의 변화는 음악 소비자들의 이용패턴의 변화와 함께 나타나며, 여러 매체의 복합적인 영향이 음악 소비자들의 선호도에 추가적인 영향을 미친다. 본 논문에서는 소유에서 소비로 빠르게 진화하고 있는 국내 음악 소비자들의 이용패턴을 AIDMA 모델과 AISAS 모델의 관점과 통계의 추이를 살펴보고 분석해 보았다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.125-128
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• 2001

A finite element-based, integrated process model is presented for coupled analysis of the thermal and metallurgical behavior of the strip occurring on the run-out-table in hot strip rolling. The validity of the proposed model is examined through comparison with measurements. The models capability of revealing the effect of cooling pattern on strip temperatures and the optimal cooling pattern are demonstrated through a series of process simulation. In order to improve strip shape and control temperature history of thickness direction for strip during ROT cooling.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제10권2호
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• pp.41-47
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• 2006

The Renewal process and the Non-homogeneous Poisson process (NHPP) process are probably the most popular models for describing the failure pattern of repairable systems. But both these models are based on too restrictive assumptions on the effect of the repair action. For these reasons, several authors have recently proposed point process models which incorporate both renewal type behavior and time trend. One of these models is the Modulated Power Law Process (MPLP). The Modulated Power Law Process is a suitable model for describing the failure pattern of repairable systems when both renewal-type behavior and time trend are present. In this paper we propose Bayes estimation of the next failure time after the system has experienced some failures, that is, Mean Time Between Failure for the MPLP model. Numerical examples illustrate the estimation procedure.

• 한국보건간호학회지
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• 제11권2호
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• pp.83-93
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• 1997

This study was done for the purpose of investigating college students' body weight and health behavior. The subjects for this study were 1421 students obtained by a convenient sampling from one junior college located in Mok-Po. The data were analyzed by self-reporting questionnaire from June 18 to 28, 1996. The data were analyzed by descriptive statistics with SAS program. The results were as followed; Factors of comparatively high contribution to overweight were male students, perception they were healthy. smoking, alcohol drinking, irregular sleep and eating pattern, sleep for 9 hours over, regular exercise, no snack, diet control for weight loss. Factors of comparatively high contribution to underweight were female students. perception they were unhealthy. no smoking and alcohol drinking. irregular sleep and eating pattern. high rate of snack, sleep for 9 hours over. In conclusion overweight and underweight were correlated with seven health habits' and we suggest health education related to seven health habits.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년도 추계학술발표대회 논문집
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• pp.168-173
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• 2009

The purpose of this study was to analyze behavioral patterns of elderly residents and to identify the characteristics of using furniture and home appliances by elderly-headed households. For this purpose, field studies that included observation and open-ended interview were conducted with 52 households. The data was analyzed with frequency, chi-square test by SPSS 14.0 for windows. The major findings of this study were that: 1) Elderly households had more sitting-down style furniture which was a traditional living mode than western style furniture. 2) They experienced inconvenience to use home appliances that were not designed for the aged. 3) Their behavioral patterns were related with family type and income.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2011년도 추계 총회 및 창립 30주년 기념 심포지엄
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• pp.3-21
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• 2011

Laboratory experiments and numerical simulations using Particle Flow Code (PFC2D) were performed to study the effects of joint separation and joint overlapping on the full failure behavior of rock bridges under direct shear loading. Through numerical direct shear tests, the failure process is visually observed and the failure patterns are achieved with reasonable conformity with the experimental results. The simulation results clearly showed that cracks developed during the test were predominantly tension cracks. It was deduced that the failure pattern was mostly influenced by both of the joint separation and joint overlapping while the shear strength is closely related to the failure pattern and its failure mechanism. The studies revealed that shear strength of rock bridges are increased with increasing in the joint separation. Also, it was observed that for a fixed cross sectional area of rock bridges, shear strength of overlapped joints are less than the shear strength of non-overlapped joints.

• 한국해양공학회지
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• 제10권3호
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• pp.105-116
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• 1996

In this paper, we report the experimental results for the flow pattern and the material transport around a cavity subject to a sinusoidal external flow at the far region to ward the open side of the cavity. A tilting mechanism is used to generate a oscillatory flow inside a shallow rectangular container having a cavity at one side. The surface flow visualization is performed to obtain the unsteady behavior of vortices generated at two edges situated at the entrance of the cavity. It was found that at the period 4.5 sec., the behavior of the vortices is asymmetric, and there exists a steady residual flow in the cavity. The bottom flow patterns are also visualized. There are two regions outside of the cavity where the bottom fluid particles concentrate. The material transport in this flow model is very peculiar; fluid particles in the cavity flows outward through the passage along the walls starting from the edges, and particles in the outer region approach the cavity from the central region.

• 한국전자통신학회논문지
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• 제9권2호
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• pp.261-266
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• 2014

국내 보안관제센터들의 현황을 검토하였으며, 보안관제 체계의 특징인 패턴기반 보안관제체계와 중앙집중형 보안관제 체계에 대한 분석과 장단점을 분석하였다. 또한 국내 보안관제 체계 발전방안에서는 기존 패턴 기반의 중앙집중형 관제 체계가 가지고 있는 문제점을 개선하기 위해 이상행위 탐지기반의 허니넷과 다크넷을 분석하여 이를 적용한 발전 방안을 기술하였다.

• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1726-1732
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• 2007

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. Anomaly detection is a pattern recognition task whose goal is to report the occurrence of abnormal or unknown behavior in a given system being monitored. This paper presents an efficient rough set based anomaly detection method that can effectively identify a group of especially harmful internal attackers - masqueraders in cellular mobile networks. Our scheme uses the trace data of wireless application layer by a user as feature value. Based on this, the used pattern of a mobile's user can be captured by rough sets, and the abnormal behavior of the mobile can be also detected effectively by applying a roughness membership function with the age of the user profile. The performance of the proposed scheme is evaluated by using a simulation. Simulation results demonstrate that the anomalies are well detected by the proposed scheme that considers the age of user profiles.