• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.407-408
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• 2006

Passenger safety is one of the most important considerations in the purchase of an automobile. A curtain-type air bag is increasingly adapted in deluxe cars for protecting passengers from the danger of side clash. Inflator housing is a main part of the curtain-type air bag system for supplying high-pressure gases to pump up the air bag-curtain. Although the inflator housing is fundamental in designing a curtain-type air bag system, flow information on the inflator housing is very limited. In this study, we measured instantaneous velocity fields of a high-speed flow ejecting from the inflator housing using a dynamic PIV system. From the velocity field data measured at a high frame-rate, we evaluated the variation of the mass flow rate with time. From the instantaneous velocity fields of flow ejecting from the airbag inflator housing in the initial stage, we can see a flow pattern of broken shock wave front and its downward propagation. The flow ejecting from the inflator housing was found to have large velocity fluctuations and the maximum velocity was about 700m/s. The velocity of high-speed flow was decreased rapidly and the duration of high-speed flow over 400m/s was maintained only to 30ms. After 100ms, there was no perceptible flow.

• 한국벤처창업학회:학술대회논문집
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• 2018.04a
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• pp.67-74
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• 2018

소상공인 창업자들이 자금조달의 대부분을 은행 대출에 의존하고 있는 가운데 소규모 자금 조달을 필요로 하는 이들을 위해 핀테크 기반의 새로운 금융서비스를 통해 소상공인 창업자의 금융 공급을 확산할 필요가 있다. 이러한 환경 변화 패러다임에서 본 연구는 빅데이터와 핀테크 솔루션의 활용이 소상공인의 매출과 금융지원에 미치는 영향을 살펴보기 위해 실제로 공공과 민간의 상권빅데이터자료를 수집하여 분석을 수행하였다. 이를 통해 소상공인에 대한 금융혜택 증대를 위한 사업장의 매출증대 등 소상공인 창업자의 사업성 평가에 필요한 주요변수들을 상권빅데이터를 실증적으로 분석하여 효과성을 검증하는 것이 본 연구의 목적이다. 특히 자금의 대부분을 정책자금을 통해 조달하는 소상공인들이 일반 은행에서도 중소기업 대출의 하나로 비중 있게 이루어질 수 있도록 기존에 활용되지 못한 빅데이터 변수들을 탐색하여 소상공인의 경쟁력 향상을 위한 효율적인 금융지원이 가능함을 확인하고자 하였다. 본 연구에서는 소상공인 창업자의 대출 등 금융지원 확대를 위한 사업성 평가에 상권빅데이터의 활용 가능성이 있는지를 중심으로 문헌적 연구방법 연구와 실증적 분석을 병행하였다. 본 연구는 핀테크와 빅데이터의 활용이 향후 소상공인 자금 조달의 발전 방향이 어떻게 되어야하는지를 모색해야하며, 소상공인을 포함하는 중소기업 신용평가방식의 발전 방향을 구체적으로 모색되어야 할 시점임을 의미하고 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1038-1043
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• 1997

To adapt the neural network proess for the purpose of determination of optimal utting onditions (optimal cutting speed and feed rate), some selection strategies for the machining factors are necessary, which is considered planning cutting process. In this case, factors that have both nonlinearity and strong relationship must be selected. Although tool grade and chemical properties of workpiece material have strong effect to cutting speed, it's not easy to find a analytic relation between them. In this paper, a mathematical method for determining the optimal amount of cutting (depth of cut, feed rate) is presented by tool goemetry and heat generation during cutting process. And various tool grade and workpiece material groups ase classified based on its chemical properties. Thier chemical composition and hardness are used as input pattern for neural network learnig. The result of learning shows the relationship between tool grade and workpiece material and it is proved that it can be used as a sub-system for automatic process planning system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1848-1852
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• 2003

Generally, burrs refer to projected parts remained on the edge after material had been processed. These burrs decrease the precision of part and cause many problems in part assembly. Burrs are undesirable projections of the material beyond the edge of the workpiece. A number of deburring processes have been developed such as barreling, brushing, chemical methods etc. But, there are a few publications in the area of applying ultrasonics to deburring. When ultrasonic vibration propagates in the liquid medium, a large number of bubbles are formed. These bubbles generate an extremely strong force, which removes burrs. Cavitations were used as a term to describe erosion of parts caused by the action of cavities in liquid. The object of this study is to analyze the effects of ultrasonic cavitation in deburring process. For this purpose, we introduce a new ultrasonic cavitation method with abrasive, which efficiently removes the burrs. Experimental parameters to verify the deburring effects of ultrasonic cavitations are ultrasonic power, amplitude, distant of the transducer from the workpiece, deburring time and abrasive. It has been shown that deburring with ultrasonic cavitation in water is effective to burrs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1816-1819
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• 2003

As a result of milling operation, we expect to have burr at the outward edge of workpiece. Also, it causes undesirable problems such as deburring cost, low quality of machined surface, and bottleneck in manufacturing process. Though it is impossible to totally remove burr in machining, it is necessary to plan a machining process that minimizes the occurrence of burr. In this paper, a scheme is proposed which identifies the tool path of the milling operation with minimum burr. In the previous research, a Burr Expert System was developed where the feature identification, the cutting condition identification, and the analysis on exit burr formation are the key steps in the program. The Burr Expert System predicts which portion of workpiece would have the exit burr in advance so that we can calculate the burr length of each milling operation. Here, the critical angle determines whether the burr analyzed is an exit burr or not. So the burr minimization scheme becomes to minimize the burr with critical angle. By iterating all the possible tool paths in certain milling operation, we can identify the tool path with minimum burr.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.207-210
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• 2007

As the Internet is prevalent in our life, harmful contents have been increasing on the Internet, which has become a very serious problem. Among them, pornographic video is harmful as poison to our children. To prevent such an event, there are many filtering systems which are based on the keyword based methods or image based methods. The main purpose of this paper is to devise a system that classifies the pornographic videos based on the audio information. We use Mel-Cepstrum Modulation Energy (MCME) which is modulation energy calculated on the time trajectory of the Mel-Frequency cepstral coefficients (MFCC) and MFCC as the feature vector and Gaussian Mixture Model (GMM) as the classifier. With the experiments, the proposed system classified the 97.5% of pornographic data and 99.5% of non-pornographic data. We expect the proposed method can be used as a component of the more accurate classification system which uses video information and audio information simultaneously.

• Journal of the Korean Dietetic Association
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• v.22 no.1
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• pp.41-52
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• 2016

This study was performed to investigate the health status and food habits of male college students in Wonju according to drinking behavior. A total of 204 (drinking group: 133, non-drinking group: 71) male college students were recruited and a questionnaire-based survey was conducted. General characteristics, drinking-related factors, health status, and food habits were investigated. Data were analyzed by SPSS program (ver 21.0). The type of residence (P<0.05) and obesity rate (P<0.05) were significantly different by drinking status. Frequency of drinking was 65.2%, and 39.9% of subjects started drinking upon entering college. The motivation to start drinking was 'from necessity'. Reason for drinking was 'Social relations'. The most frequent drinking opportunity in college was 'membership training'. The favorite kind of drink was beer. Health status factor scores for 'concerns about health (P<0.05)', and 'smoking (P<0.05)' were significantly higher in drinking group than those in non-drinking group. Food habits score (drinking group: 50.9 vs non-drinking group: 52.4, P<0.01) was significantly lower in the drinking group. Scores for 'I have breakfast regularly (P<0.05)', 'Do not eat the junk food often (P<0.05)', and 'Do not eat out often (P<0.05)' were significantly lower in the drinking group. 'Drink milk every day' was significantly higher in the drinking group.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.05a
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• pp.45-49
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• 2005

최근 해안송림에 대한 관심이 높아지고 있고, 이를 효과적으로 보전, 활용해야한다는 목소리가 높지만, 국내에서는 이러한 해안송림이 어떻게 변천되고 지역에 어떻게 기능해 왔는지 아직 알려지고 있지 않다. 본고는 해안송림의 기초연구로서, 하동송림을 대상으로 이러한 해안송림의 사회적인 기능과 관리문제를 검토한 것에 있다. 하동송림을 사례로 조사한 결과, 해안송림은 송림이 지역과 밀착함으로써 주민의 레크레이션기능은 물론 외부관광객을 끌어들일 수 있는 지역발전의 중요한 소재가 될 수 있는 것으로 나타났다. 또한 해안 송림이 지역주민의 일상생활과 밀접히 연관되고 지역발전의 한 축으로서 기능하면서, 송림에 대한 관리 및 주체의식이 높아지는 것으로 나타났다. 이러한 지역발전의 실질적 기능 및 자연스러운 관리의식의 고양은 일반 공원이나 원거리 해안림 등에서는 쉽게 나타나지 않는 것으로서, 마을 숲(해안송림 등)이 갖고 있는 하나의 중요한 잠재력이 아닌가 생각된다. 그러나 관리측면에서는 하천오염이 해결되지 않고, 송림확장계획이 중지되고, 소나무재선충 방지책에 의문에 제기되는 등 적지 않은 문제가 나타나고 있다. 또한 이러한 문제발생의 원인으로는 해안송림에 대한 기본적인 인식의 부족, 책임 있는 관리주체의 부재, 구체적인 연구의 부족 등이 검토된다. 해안송림의 기능과 식생은 고정되어 있는 것이 아니라 지역 환경에 따라 끊임없이 변화되는 것에 있어, 변화에 대응하는 개발논리가 필요하다. 따라서 이러한 특수성을 일반적 임업관리나, 시설보수 차원에서의 접근은 소중한 지역의 자산과 발전기회를 잃은 거와 다르지 않다. 소중한 지역자원의 가치를 빛내고, 보다 효과적인 활용을 위해서는, 보다 체계적이고 파지티브한 관리 및 활용 정책이 요구되는 것에 있고, 이를 위해서는 책임 있는 관리주체를 조직하는 것과 함께, 토지사병에 기초한 송림의 이용 및 식생 변화에 대한 연구가 필요한 것으로 판단된다.

• Journal of Yeungnam Medical Science
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• v.21 no.1
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• pp.114-119
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• 2004

This report concerns an unusual case of acute postoperative pulmonary edema without any apparent causes in a 45-year-old man. The patient was subjected to the removal of a previously placed device on the left tibia, and the excision of a benign mass on the right forearm. Unexpected acute bilateral pulmonary edema occurred immediately after the completion of the procedures. The etiologies were reviewed in relation to the patient's condition and clinical manifestations. Fluid overloading was excluded as a cause in view of the patient's perioperative state and postoperative chest X-ray results. We could not find any symptoms of upper airway obstruction during emergence from general anesthesia. We had doubts about tourniquet or fentanyl-induced pulmonary edema, but these factors were not sufficient to bring about pulmonary edema in this case. To our knowledge, the cause of acute pulmonary edema in this case is indeterminate.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.622-627
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• 2001

The object of this paper is to compare stress intensity factor that be calculated by Raju-Newman's equation, finite element method, and Vessel INTegrity analysis inner flaws(VINTIN) program for longitudinal semi-elliptical cracks in cylindrical vessel under inner pressure. For this, three-dimensional finite-element analyses were performed to obtain the stress intensity factors for various surface cracks with t/R = 0.1. The finite element meshes were designed for various crack shapes with t/R of 0.1. The crack depth to thickness ratio, a/t, was set to 0.2 and 0.5 matching Raju-Newman's equation. The crack depth to length ratio, a/c, was set to 0.2 and 0.4 in the same way and 0.33 was added to extend the range of crack configuration. Finite Element Analyses(FEA) were performed using the commercial FEA program ABAQUS. The results showed that the Raiu-Newman solutions were about 4-10% lower than FEA's using symmetric model of one-eighth of a vessel and close to those of FEA using symmetric model or one-forth or a vessel. Ana VINTIN solutions were nearly equal to those or Raju-Newman.