• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.432-437
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• 2016

The behavior of a bellows for an electromagnetic control valve was investigated. The bellows consists of an outer metal bellows, inner spring, and metal caps. The bellows needs to have sensitive and precise motion against external loads and pressure loads in order to control the position of the valve accurately. The spring constant of the inner spring and load-displacement curve of the bellows set were measured using a test machine. The inner spring showed a linear relation between load and displacement. The bellows set showed small stiffness at small displacement, and then the stiffness slightly increased upon subsequent displacement. Based on the measured data, finite element analysis was performed. Axisymmetric conditions were applied, and shell elements were used. The effective material properties of the outer bellows material were extracted. Additional analysis was performed, and the behavior of the bellows was analyzed using the finite element model.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.3
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• pp.226-232
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• 2014

In the present study, the characteristics of laser ultrasound in the ablation regime are investigated using simulations and experiments. The laser ultrasonic technique has been recognized as a noncontact method in the field of nondestructive tests (NDTs). In hostile environments (such as hot temperatures), this method has various advantages over the conventional contact ultrasonic method. In particular, in the ablation regime, the laser ultrasonic technique is suitable for inspecting internal defects because of the high amplitude and directivity of the longitudinal wave. In this paper, a simulation model for laser ultrasound in the ablation regime was developed. This model was subsequently applied to a defective specimen using the B-scan method to locate defects. Finally, we performed an experimental test to verify the simulation results. Consequently, the simulation demonstrated good agreement with the experimental test.

• The Journal of the Acoustical Society of Korea
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• v.15 no.5
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• pp.44-52
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• 1996

Acoustical characteristics of internal pipe structures and a loudspeaker of the thermoacoustic refrigerator are analyzed by using the transfer matrix method. The resonator system is dismantled into verious basic acoustic elements, and then linearized transfer matrices are serially combined with the dynamical system of linearized loudspeaker model, that the total system of thermoacoustic refrigerator can be analyzed in terms of frequency characteristics and acoustic field shape. Additionally, by using equations for energy flow through the capillary stack, the temperature distribution over the stack is numerically estimated. After expressing the acoustic work flow, thermoacoustic flow, and energy loss per unit length in a single capillary duct by using the transverse functional variations, overall energy flow rate and energy balance are obtained for the whole capillary stack. The final expression for energy flow through the stack is numerically evaluated by varying physical parameters obtained from the sound field analysis. After confirming good agreements between predicted and experimental results for the interior sound field of a refrigerator model, the thermoacoustic characteristics of Hofler's apparatus is analyzed by the proposed method and it is observed that the results agree well with Hofler's experimental results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.1-8
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• 2020

In the case of power plant facilities, seismic stability of non-structural elements is important. In particular, Cabinet structures to which electrical equipment is attached, should have functional safety against earthquakes. Therefore, in this study the dynamic characteristics of non-structural elements inside existing power plant buildings were identified and the response level generated during dynamic behavior was analyzed. In addition, The steel plate dampers were adopted and adjusted to suit the size of the target equipment. In order to derive the optimal seismic reinforcement, the variables according to the attachment location were set and the responses were analyzed by the seismic movement input before and after reinforcement.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.235-246
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• 2012

Typhoon induced surge simulations are done to make an establishment of coastal disaster prevention plan. To apply efficient run-up and overtopping on vertical harbor docks, in which prevailing wet-dry scheme cannot be satisfied due to infinite steepness, an imaginary internal barrier concept introduced and analyzed. Before real application on the Mokpo harbor area, feasibility tests are done on an idealized simple geometry and as a result it is found that the moderate width of the barrier might be 1 m. The threshold value of the minimum wet depth $H_{min}$ for land area, which behaves sensitive role in inundation area and depth, depends on grid size. However it is revealed that 0.01 m is adequate value in this fine finite element with 10 m spacing. A hypothetical typhoon of 100 years return period in central pressure and maximum velocity is generated based on historical tracks. Simulation of possible inundation on Mokpo area is performed with asymmetrical vortex of hypothetical typhoon and wave coupling. Model results show general agreement in pattern compared to other's prediction, however possibility of inundation enlargement is expected in harbor area.

• Environmental Analysis Health and Toxicology
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• v.21 no.3 s.54
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• pp.219-228
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• 2006

폴리우레탄, 폴리에스테르, 바이페놀, PVC 외 각종 농약 등을 생산하는 울산의 모 화학공장에서, 다양한 종류의 휘발성유기화합물질들(VOCs)이 배출되고 있다. 평균적인 휘발성유기화합물질의 배출 농도는 7283 ppm으로, 톨루엔, 페놀을 포함하여 Trimethyl-pentene, trimethyl-hexene, dimethyl-cyclohexane 등이 검출되었다. Trimethyl-pentene, trimethyl-hexene, dimethyl-cyclohexane등은 인화성이 강하며 화재를 일으킬 위험성이 매우 큰 것으로 알려져 있고, 특히 톨루엔과 페놀의 경우는 호흡이나 피부접촉 등을 통한 인체로의 유입이 있을 경우 유독성을 나타내게 된다. 이러한 VOCs제거를 위하여 겨울철 기간에 파이로트-규모의 바이오필터 적용 실험이 진행되어 졌다. 본 연구의 목적은 바이오필터 운영이 진행되는 가운데 온도, 함수비, 하중, 압력손실 등의 제한요소들이 미디어 내부에서 변화하는 상황에 대한 관찰 및 평가에 있다. 이러한 제한요소들은 바이오필터의 디자인과 오염물질 제거에 심대한 영향을 미치게 된다. 바이오필터는 옥외에 설치되어 총 44일간 운영되어 졌는데, 외부 영하온도의 영향을 최소화하기 위하여, 7cm두께의 파이버-글래스 소재 단열설비가 반응기 외부에 설치되었고 또한 $150^{\circ}C$의 스팀이 바이오필터 반응기와 단열설비 사이에 제공되어 졌다. 바이오필터 반응기 내부에는 23개의 온도 측정 센서와 함수비 센서, 공기샘플포트, 습도계 등이 각기 다른 장소에 설치되어 온도, 함수비 등의 제한요소 영향연구가 진행되었다. 미디어 내부 같은 높이의 서로 반대되는 위치에서 온도차가 13.7도에서 -8.3도까지 차이가 나는 것으로 관찰되었으며, 미디어 높이 위치의 변화에 따라서도 21도에서 2도가지 차이를 나타냈다. 바이오필터 함수비는 실험기간 동안 지속적으로 변화가 발생하였는데, 스팀이 제공되는 동안에는 미디어 함수비가 훨씬 빠른 속도로 증가됨이 관찰되어 졌다.

• Journal of Global Scholars of Marketing Science
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• v.4
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• pp.53-86
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• 1999

오늘날 기업간 M & A가 활발히 진행되면서 브랜드 자산가치에 대한 연구는 학계와 실무계에 있어 커다란 관심이 집중되면서 브랜드의 역할에 대해서 다양한 새로운 관점이 제시되고 있다. 브랜드 자산가치와 관련한 기존의 연구들은 주로 평가에 관한 것이 대부분이었으나 최근에 와서 브랜드 자산가치의 중요성이 부각됨으로써 브랜드 자산가치의 형성에 대한 영향요인의 연구가 활발히 이루어 지고 있다. 하지만 이틀 연구의 대부분은 제품 품질과 광고톨 중심으로 한 기업의 통제 변수인 마케팅믹스-4P(product, price, place, promotion)-에 연구의 초점을 맞추고 있다. 하지만, 오늘날 기술혁신에 힘입어 규모의 경제성이나 경험효과에 의한 비용 우위는 거의 기대될 수 없게 되었고, 품질에서도 기업간의 격차가 현저히 줄어들었다. 그러고 막대한 비용의 문제로 인하여 매스미디어등의 광고를 통한 브랜드 자산가치의 형성이 결코 쉬운 일이 아니다. 특히 오늘의 국내의 기업현실을 감안하면 더욱 어려운 실정이다. 따라서, 본 연구에서는 기존의 연구에서 다루지 않았던 고객만족 실현를 위한 핵심개념인 내부마케팅과 다양한 소비자 욕구에 있어 신속히 대응하는 브랜드 수의 증가를 브랜드 자산가치의 형성에 대한 새로운 영향요인으로 선정하여 마케팅믹스 요인과 더불어 이들의 영향성을 실증분석을 통하여 검증하였다. 본 연구의 결론을 이용하여 다음과 같은 브랜드 자산가치에 대한 마케팅에 있어서 전략적 시사점을 제안한다. 첫째, 브랜드 자산가치톨 형성 내지 강화하기 위해서는 내부마케팅 요인, 브랜드수의 증가요인, 마케팅믹스 요인중에서 어느 한 요인만으로 한계가 있기 때문에 3가지 요인을 동시에 활용하여 시너지 효과를 노려야할 것이다. 아울러 다양화, 세분화되어 가고 있는 소비자 니즈에 신속히 대용하기 위해서는 브랜드의 수의 증가를 통한 마케팅전략으로의 실천이 시의 적절한 방법중 하나라고 판단된다. 둘째, 기존의 많은 연구에서 알 수 있듯이 그동안 브랜드 자산가치의 구성요소에 대한 영향 요인으로 마케팅믹스적 요인을 주로 다루어 왔는데, 본 연구 결과에 의하면 내부마케팅요인과 브랜드수의 증가요인도 브랜드 자산가치의 구성요소에 많은 영향을 미치는 것으로 나타났기 때문에 기업들은 이들 요인에 대한 세밀한 검토와 관심이 요구된다. 셋째, 기업들은 향후 브랜드 자산가치를 증대하기 위한 장기적이고 전략적인 관리방안이 요구된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.513-520
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• 2018

This research concerns the characteristics of tank barrel inner flow according to the barrel length and the pressure of ammunition when fired. By analyzing the flow characteristics of the bore evacuator according to barrel length and ammunition pressure regarding ammunition design, it is possible to prevent the flareback phenomenon that may occur during ammunition operation. Through bore evacuator flow analysis by barrel length and ammunition pressure, we identified key design factors concerning barrel and ammunition compatibility including speed, accuracy, penetration performance and range. Test results found if barrel length is long and ammunition pressure is low, bore evacuator operation time is slow. Therefore, there is a high probability that propellant gas will enter the battle vehicle. Therefore, the correlation analysis method of bore evacuator flow characteristics based on barrel length and ammunition pressure is considered as a primary method to improve operational performance. When designing new ammunition, the correlation analysis method will be used to determine ammunition weight and select the propellant pressure.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.132-142
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• 2018

This study attempts to identify the external and internal factors which affect collaboration motives and investigates their respective impacts from the perspective of foreign direct investment(FDI). Although there has been much research on collaboration motives, so far, few studies have associated collaboration motives with FDI. The findings suggest that while price competitiveness and cost structure uncertainty have a positive and significant impact on collaboration motives, the gross added value to property as well as plant and equipment have a significant negative impact. Furthermore, in the case of gross added value to both property and plant and equipment, managers tend to collaborate with others to enhance the value of these factors. For both FDI and non-FDI firms, internal factors such as price competitiveness and investment within three years are significant determinants for the decision to collaborate. The difference between FDI and non-FDI firms is that for the former, the gross added value to property, an internal factor, is a critical factor, while for the latter, the cost structure uncertainty, an external factor, is critical for collaboration. To summarize, this study suggests the following managerial implication: the enhancement of the internal competency of a firm broadens the window of opportunity for collaboration with others, and consequently provides a chance to boost management efficiency.

• Journal of Korea Port Economic Association
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• v.27 no.3
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• pp.273-288
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• 2011

Recently, the rankings of Korean container ports in terms of container handling cargo volume were plunged down due to the emerging Chinese ports. The efficient container ports strategies which increase container port competitiveness were requested. In this respect, it is urgently required to draw out constituent factors for Port Logistics, weigh these factors, and finally focus on improving the suggested factors. The aim of this paper is to evaluate weight and priority values for 'inner consisted factors' and 'outer requested factors' of port logistics by using the AHP(Analytic Hierarchy Process) method. As for the analysis regarding the inner consisted factors, the results were shown as follows: a storage and handling system (0.288) as the first rank; an information system of port logistics (0.210) as the second rank; an inland intermodal system (0.189) as the third rank; a ship's entering and departuring system (0.184) as the fourth rank, and a ship's berthing system (0.129) as the fifth rank. In terms of analysis regarding outer requested factors, the results came out as follows: a logistics cost (0.360) as the first rank; a port service (0.128) as the second rank; a connectivity (0.118) as the third rank; a hinterland condition (0.116) as the fourth rank; an convenience (0.106) as the fifth rank; a regional center (0.095) as the sixth rank, and an availability (0.077) as the seventh rank. For analyzing the priorities changes in constituent factors, the comparison of results between the year 2007 and the year 2011 was done. As the results, among inner consisted factors, 'information system of port logistics' was ranked first in the year 2007 while 'a storage and handling system' became the most important factor in the year 2011. Among the inner consisted factors, however, the logistics cost was the important factor in 2007 and 2011, respectively.