• Title/Summary/Keyword: structural analysis and design

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Field Scale Study for Energy Efficiency Improvement of Crematory System by the Shape Optimization of Combustion Chamber (화장로 형상 최적화를 통한 에너지효율개선을 위한 실증연구)

  • Won, Yong-Tae;Lee, Seung-Mok
    • Applied Chemistry for Engineering
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    • v.30 no.5
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    • pp.546-555
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    • 2019
  • The purpose of this study was to improve the performance of the bogie-type crematory, which is the mainstream of domestic crematory equipment. A field scale technology was investigated via increasing the volume by changing the shape of the furnace and reducing the cremation time and saving the energy usage through the optimization of burner combustion control. First, the optimized structural design through thermal flow analysis increases the volume of the main combustion chamber by about 70%, which increases the residence time of the combustion flue gas. A designed pilot crematory was then installed and the combustion behavior was tested under various operating conditions and the optimum operating plan was derived from for each furnace shape. Based on the results, the practically applicable crematory was designed and installed at Y crematorium in the P City. Optimal combustion conditions could be derived through operating the demonstration crematory furnace. The crematory time and fuel consumption could be minimized by increasing the energy efficiency by increasing the residence time of high temperature combustion flue gas. In other words, the crematory time and fuel consumption were 38 min and $21.8Nm^3$, respectively which were shortened by 44.1 and 54.4% lower than that of the existing crematory, respectively.

A Study of the Effect of Purchasing Factors on Customer Satisfaction and Repurchasing Intention of Chinese Residents in Korea Buying through Internet Shopping Malls (한국거주 중국인들의 인터넷 쇼핑몰에서의 구매요인이 고객만족, 재구매의도에 미치는 영향에 관한 연구)

  • Kim, Moon-Hong
    • Journal of Distribution Science
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    • v.14 no.11
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    • pp.139-147
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    • 2016
  • Purpose - This study examines the effects of purchasing factors of consumers based on customer satisfaction and repurchasing intention buying through Internet shopping malls. The subject of this study are Chinese residents who have lived over a year in Korea. Research design, data, and methodology - In this study, former research related with internet shopping malls' customer satisfaction and repurchase intention was revised. Based on past research, the internet shopping mall purchasing factors divided to 4 factors; factors of product, price, service, and promotion. 5 hypotheses were made. They are

    Product factors of internet shopping malls have meaningful effect to customer satisfaction,

    Price factors of internet shopping malls have meaningful effect to customer satisfaction,

    Service factors of internet shopping malls have meaningful effect to customer satisfaction,

    Promotion factors of internet shopping malls have meaningful effect to customer satisfaction,

    Customer satisfaction factors of internet shopping malls have meaningful effect to customer repurchase intention. Measurements developed 4~5 items to each factor and questionnaires were made. The survey was conducted on 1,000 Chinese people. Out of 292 surveys, 9 were excluded which responded nothing or were unfilled. Finally 283 surveys were used in empirical analysis with SPSS 22.0 statistical program. Hypotheses were verified by structural equation modeling. Results - The following conclusions are shown in the empirical study. First, the service and promotion factors of internet shopping mall have effects on customer satisfaction. Second, customer (Chinese people who live in Korea) satisfaction have effects on repurchase intention. Third, the products value and price level of internet shopping mall have strong effects on repurchasing intention. Conclusions - There are suggestions that Chinese customers satisfied with Korean internet shopping malls might increase their royalty to the shopping malls as possibility of repurchase arises. This study has differentiating points with preceding researches that subjected residents in Korea. But there are limitations that this study also used purchasing factors used in preceding studies. Also this study has limitations, such as generalization in global market circumstances because this study subjected only Chinese people and not global customers. Therefore, further study executed complementary with those limitations would be an interesting study.

Design of Summer Very Short-term Precipitation Forecasting Pattern in Metropolitan Area Using Optimized RBFNNs (최적화된 다항식 방사형 기저함수 신경회로망을 이용한 수도권 여름철 초단기 강수예측 패턴 설계)

  • Kim, Hyun-Ki;Choi, Woo-Yong;Oh, Sung-Kwun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.23 no.6
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    • pp.533-538
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    • 2013
  • The damage caused by Recent frequently occurring locality torrential rains is increasing rapidly. In case of densely populated metropolitan area, casualties and property damage is a serious due to landslides and debris flows and floods. Therefore, the importance of predictions about the torrential is increasing. Precipitation characteristic of the bad weather in Korea is divided into typhoons and torrential rains. This seems to vary depending on the duration and area. Rainfall is difficult to predict because regional precipitation is large volatility and nonlinear. In this paper, Very short-term precipitation forecasting pattern model is implemented using KLAPS data used by Korea Meteorological Administration. we designed very short term precipitation forecasting pattern model using GA-based RBFNNs. the structural and parametric values such as the number of Inputs, polynomial type,number of fcm cluster, and fuzzification coefficient are optimized by GA optimization algorithm.

Comparison Study of the Impact Response Characteristics of Fixed Cylindrical Offshore Structures Considering Seawater Fluid Region (해수유체영역을 고려한 고정식 실린더형 해양구조물의 충격응답특성 비교연구)

  • Lee, Kangsu;Hong, Keyyong
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.4
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    • pp.489-494
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    • 2015
  • This research focused on minimizing the response of fixed cylindrical offshore structures to a ship impact considering the seawater fluid part. A collision between a ship and offshore structure is generally a complex problem and it is often impractical to perform rigorous finite element analyses to include all the effects and sequences during the collision. The structural behavior of a fixed cylindrical type offshore substructure with a seawater fluid part has a simpler response and small deformation due to the dissipation of impact energy. Upon applying the impact force of a ship to the cylindrical structure, the maximum acceleration, internal energy, and plastic strain are calculated for each load cases using Ls-dyna finite element software. In the maximum cases 2.0 m/s velocity, the response result for the structure was carried out to compare between having a fluid region and no fluid region. Fluid-structure interaction analysis was performed using the ALE method, which make it possible to apply a fluid region on the impact problem. The case of a fixed cylindrical type offshore structure without a seawater fluid part can be a more conservative design.

A Study on the Designer's Post-Evaluation of Gyeongui Line Forest Park Based on Ground Theory - Focused on Yeonnam-dong Section - (근거이론을 활용한 설계자의 경의선숲길공원 사후평가 - 연남동 구간을 중심으로 -)

  • Kim, Eun-Young;Hong, Youn-Soon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.3
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    • pp.39-48
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    • 2019
  • This research is based on the analysis of in-depth interviews of designers who participated in the design of the Yeonnam-dong section, which was completed in 2016. The case study site has received many domestic and foreign awards and is receiving very positive reviews from actual users. 53 concepts were derived from the open coding of the ground theory methodology. Thirty-four higher categories incorporated the concepts and 18 higher categories that reintegrated them. Later, the six categories of the ground theory were interpreted as the paradigm, and it was determined that the aspects of 'will of client' and 'work efficiency', 'site resources' and 'field manager's specialty' were the categories that had the greatest positive impact on the park construction. The key category of this park's construction was interpreted as "a park-construction model with active empathy and communication." The results of the study and are linked to the following research proposals. First, the need to improve the trust between the client and the landscape designer and the need to improve the customary administrative procedures; second, the importance of the input of landscape experts into the park construction process; third, the importance of all efforts to develop the design; fourth, the importance of on-site circular resources and landscape preservation; and fifth active social participation to increase the opportunity. This study, which seeks to grasp the facts that existed behind the park's construction, which received excellent internal and external evaluations, and has a qualitative, objective and structural interpretation of the social network related to the park's construction, in contrast to the conventional quantitative post-evaluation. It is expected that the administration and system improvements related to landscaping will be further improved through the continuation of in-depth post-evaluation studies.

Analysis of Subwavelength Metal Hole Array Structure for the Enhancement of Quantum Dot Infrared Photodetectors

  • Ha, Jae-Du;Hwang, Jeong-U;Gang, Sang-U;No, Sam-Gyu;Lee, Sang-Jun;Kim, Jong-Su;Krishna, Sanjay;Urbas, Augustine;Ku, Zahyun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.334-334
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    • 2013
  • In the past decade, the infrared detectors based on intersubband transition in quantum dots (QDs) have attracted much attention due to lower dark currents and increased lifetimes, which are in turn due a three-dimensional confinement and a reduction of scattering, respectively. In parallel, focal plane array development for infrared imaging has proceeded from the first to third generations (linear arrays, 2D arrays for staring systems, and large format with enhanced capabilities, respectively). For a step further towards the next generation of FPAs, it is envisioned that a two-dimensional metal hole array (2D-MHA) structures will improve the FPA structure by enhancing the coupling to photodetectors via local field engineering, and will enable wavelength filtering. In regard to the improved performance at certain wavelengths, it is worth pointing out the structural difference between previous 2D-MHA integrated front-illuminated single pixel devices and back-illuminated devices. Apart from the pixel linear dimension, it is a distinct difference that there is a metal cladding (composed of a number of metals for ohmic contact and the read-out integrated circuit hybridization) in the FPA between the heavily doped gallium arsenide used as the contact layer and the ROIC; on the contrary, the front-illuminated single pixel device consists of two heavily doped contact layers separated by the QD-absorber on a semi-infinite GaAs substrate. This paper is focused on analyzing the impact of a two dimensional metal hole array structure integrated to the back-illuminated quantum dots-in-a-well (DWELL) infrared photodetectors. The metal hole array consisting of subwavelength-circular holes penetrating gold layer (2DAu-CHA) provides the enhanced responsivity of DWELL infrared photodetector at certain wavelengths. The performance of 2D-Au-CHA is investigated by calculating the absorption of active layer in the DWELL structure using a finite integration technique. Simulation results show the enhanced electric fields (thereby increasing the absorption in the active layer) resulting from a surface plasmon, a guided mode, and Fabry-Perot resonances. Simulation method accomplished in this paper provides a generalized approach to optimize the design of any type of couplers integrated to infrared photodetectors.

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A Structural Relationship among Satisfaction with Information, Freedom to Express Opinion, Input from Employees, Trust in Management and Hotel Employees' Attitude toward Organizational Change (호텔직원들의 정보에 대한 만족, 의사표현의 자유, 직원의 의견 반영, 경영에 대한 신뢰 및 조직의 변화에 대한 태도 간의 구조적 관계)

  • Kim, Ji-Eun
    • Culinary science and hospitality research
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    • v.17 no.4
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    • pp.185-203
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    • 2011
  • It's hard for hotel organizations to survive without adaptation to changing environment, and employees' positive attitude are required. The empirical objectives of the study include, firstly, to identify individual factors to influence hotel employees' attitude toward organizational change, secondly, to investigate the effects of the individual factors on their attitude toward organizational change mediated through trust in management Derived from existing literature, three underlying dimensions of the individual factors are given; (1) satisfaction with information, (2) freedom to express opinion, and (3) input from employees. An experimental design is applied to test four hypotheses that reflect the research questions. Five star hotels in Korea are targeted to be surveyed. A total of 156 faithful cases out of 300 cases are analyzed in this study. Descriptive statistics and multivariate analysis of variance, and SEM are utilized employing the SPSS and AMOS 7. Results of this study indicate that satisfaction with information, freedom to express opinion, and input from employees are significantly related to hotel employees' attitude toward change mediated through trust in management. At the same time, it shows that trust in management directly influences their attitude toward organizational change. In conclusion, the findings of the study contribute to hotel organizational development.

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Selection of Retaining Wall System for Underground Parking Lots Expansion of Apartments (거주중 공동주택의 지하주차장확대를 위한 흙막이공법 선정)

  • Ro, Young-Chang;Lee, Chan-Sik
    • Korean Journal of Construction Engineering and Management
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    • v.9 no.2
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    • pp.99-107
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    • 2008
  • Rapidly increasing automobile supply rate according to improved economic level of life makes lack of parking space of apartments. Even though the initial design of parking space compiled with old regulations, it may not observe either new laws or requirement of inhabitants. Even if old apartments have no structural durability problem, outworn facilities and insufficient parking area may be a main reason for reconstruction. It causes waste of national resources and makes recycling issues. Additionally, irregularly parked cars make traffic obstruction to a fire engine and result in many fire accident victims. Parking problems of apartments are not only inconvenience but also serious safety issues. From these points of view, remodeling only for parking area expansion is necessary to avoid overall reconstruction of apartments. The purpose of this study is to suggest a retaining wall selection method for apartments underground parking lots expansion without evacuation of resident people. Effect factors to select retaining wall system are analyzed and weight values are calculated by applying AHP. One selection method of retaining wall is proposed by evaluating applicability and its sensitivity analysis is executed. This selection method is expected to help decision-making of retaining wall system selection.

Strength Development and Drying Shrinkage in Recycled Coal-Ash Building Material (석탄회를 재활용한 건설소재의 강도발현 및 건조수축)

  • Jo, Byung-Wan;Kim, Young-Jin;Park, Jong-Bin
    • Journal of the Korea Concrete Institute
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    • v.15 no.5
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    • pp.670-678
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    • 2003
  • Recently, since industrial waste and life waste leaped into a pollution source, the building material used now a days is striking the limit. The purpose of this paper is to investigate an application of recycled coal ash using non-sintering method in the construction field. Accordingly, compressive strength, elastic modulus and drying shrinkage were experimentally studied for hardened coal ash using the non-sintering method. Also, Lineweaver and Burk method were applied to the regression analysis of drying shrinkage for the proposal equation. Elastic modulus, compressive strength of material become the basis properties of structural design. And these properties by age for hardened coal ash are important because of change by pozzolan reaction. This hardened coal ash is weak for tensile stress like that of concrete. And drying shrinkage is very important factor to make huge tensile force in early age. In the results, although some differences were shown when comparing coal ash with mortar or concrete, the application as a building material turned out to be possible if further researches were carried out. And the shrinkage characteristic of hardened coal-ash reveals to be similar to that of moderate heat cement.

Research on Fault Tolerant Avionics Memory Design through Multi Level Cell Flash Memory Reliability Analysis (멀티 레벨 셀 플래시 메모리 신뢰성 분석을 통한 항공 전자장비용 내결함성 메모리 설계 연구)

  • Jeong, Sang-gyu;Jun, Byung-kyu;Kim, Young-mok;Chang, In-ki
    • Journal of Advanced Navigation Technology
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    • v.20 no.4
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    • pp.321-328
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    • 2016
  • Typical MLC NAND flash devices are considered less reliable than SLC NAND flash devices. Although raw bit error rate (RBER) of MLC flash had been considered approximately 1000times or more higher than that of SLC flash, recent research conducted on Google's data center shows that it is much lower than such expectation. Based on the research, we devised In Drive Data Duplication (IDDD) scheme that efficiently exploit MLC flash's sufficient capacity to improve its data reliability without structural complexity increment using SSD intrinsic firmware layer, and showed the data reliability expectation of MLC flash could be significantly higher than that of SLC flash from measured and calculated error rates. Even though RBER of SLC flash was lower than that of MLC flash in 44 out of 48 cases we studied, applying IDDD scheme, RBER of MLC flash was became lower than that of SLC in all 48 cases and uncorrectable bit error rate (UBER) of MLC flash was became lower than that of SLC flash in 45 out of 48 cases.