• Ocean Systems Engineering
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• 제9권1호
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• pp.79-95
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• 2019

The material analysis of an offshore structure is generally conducted in the contract design phase for the price quotation of a new offshore project. This analysis is conducted manually by an engineer, which is time-consuming and can lead to inaccurate results, because the data size from previous projects is too large, and there are so many materials to consider. In this study, the piping materials in an offshore structure are analyzed for contract design using a big data framework. The big data technologies used include HDFS (Hadoop Distributed File System) for data saving, Hive and HBase for the database to handle the saved data, Spark and Kylin for data processing, and Zeppelin for user interface and visualization. The analyzed results show that the proposed big data framework can reduce the efforts put toward contract design in the estimation of the piping material cost.

• 한국기계가공학회지
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• 제17권5호
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• pp.155-160
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• 2018

The materials used for 3D printing are mainly plastic and metal. These materials are usually used in the powdered form. In order to improve the surface roughness of a manufactured product, these powders should consist of small uniform spherical particles. However, the powdered forms are sold at a considerably higher price than bulk or wired materials. When a wire-type material is used instead of a powder, we can supply a relatively large amount of the material at one time as well as reduce the cost. Moreover, the use of this form of the material will increase the process efficiency. This paper deals with the technology required to feed a wire material in front of the tool movement and discusses the examples used for the verification.

• 한국건설관리학회논문집
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• 제19권3호
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• pp.52-60
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• 2018

우리나라의 공공건설공사는 입찰을 통해 공사를 발주하고 있으나 하지만 입찰의 특성상 참여자들간의 담합이 발생할 수 있다. 이에 따른 입찰담합은 발주자에게 손해를 가하는바, 이를 배상할 수 있도록 적절한 가상경쟁가격을 산정해야 한다. 이와 관련하여 계량경제학적 방법이 일반적으로 활용되고 있으나 건설공사, 특히 설계 시공일괄입찰의 특성상 여러 한계와 쟁점이 발생할 수밖에 없다. 따라서 본 연구에서는 설계 시공일괄입찰에서 합리적인 가상경쟁가격을 추정할 수 있는 방안을 제안한다. 이는 입찰 참가자가 제출한 설계도서로부터 한계비용을 도출하고, 입찰 참가자의 기술 수준과 경쟁업체의 기술 수준 및 입찰 형태에 따라 입찰율에 따른 요인을 검토하여 가상경쟁가격을 추정하는 방법이다. 본 연구에서 제안한 방법을 토대로 설계 시공일괄입찰 낙찰자 결정 방식의 특성이 반영된 합리적인 가격이 도출될 수 있으며, 답함에 따른 손해액 산정뿐만 아니라 실제 입찰 과정에서의 참고자료로 활용할 수 있을 것이라 판단된다.

• 한국건설관리학회논문집
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• 제24권6호
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• pp.66-73
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• 2023

건설 프로젝트는 기획부터 완공까지 공사비 예측, 확인, 그리고 정산 단계로 이루어진다. 건설원자재 평균 가격은 변동성을 지닌다. 하지만 건설 프로젝트의 자재비 산정은 계획단계 시점의 시세를 반영하여 결정되기 때문에, 시공단계에서 자재가 투입될 시점의 시세 변동에 따라 예상한 가격과 차이가 날 수 있다. 건설 산업은 건설원자재 가격 변동으로 인한 수요예측 실패, 프로젝트 비용변경으로 인한 사용자 비용 증가, 예측 체계성 부족으로 인한 손실이 발생한다. 이에 따라 건설원자재 가격 예측의 정확도 개선이 필요하다. 본 연구는 Data Refactor 기법의 개선을 통해 건설원자재 가격 예측 및 적용성 검증을 목적으로 한다. 건설원자재의 가격 예측의 정확도를 높이기 위하여 기존의 데이터 리팩토 간의 저·고빈도의 분류 및 ARIMAX 활용법을 빈도 위주 및 ARIMA 기법 활용으로 개선하여 건설원자재 목재, 시멘트 등 6개 품목의 단기(미래 3개월), 중기(미래 6개월), 장기(미래 12개월) 가격을 예측하였다. 분석한 결과 개선된 Data Refactor 기법을 기반으로 한 예측값이 오차는 줄었고 변동성은 확장되었다. 따라서, 본 연구에서 제안된 Data Refactor 기법을 통해 건설원자재 가격을 더 정확하게 예측하여 예산을 효과적으로 관리할 수 있을 것으로 기대된다.

• 한국기계가공학회지
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• 제17권3호
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• pp.155-162
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• 2018

Delta robots are usually used for industrial manufacturing, but heavy weight and expensive price have been obstacles to rapid propagation of robots in the field. The goal of this research is to make light-weight and price-competitive delta robots. To reduce the weight, we used plastic material for the arm link, and to reduce the price, we used a step-motor as the main actuator. First we formulated the equations of inverse kinematics for the designed delta robot and then verified these equations by using multibody-dynamics simulation. An algorithm of motion control was developed and applied to the motion-processing unit using a timer-interrupt of 8 milliseconds. Finally, we tested the performance of the new delta robot by checking its control of motion along line segments.

• 대한가정학회지
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• 제35권3호
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• pp.77-88
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• 1997

The purpose of this study was to examine the models of apparel store patronage behavior of various store types for each of two clothing categories in terms of lifestyle activities, information sources, shopping orientations and store attributes. The data were collected via a questionnaire from 326 adult females of ages over 20's living in satellite cities around Seoul and were analyzed by factor analysis, Multiple Regression analysis and path analysis. The results of this study were as follows: 1) There were significant relationships between lifestyle activities, information sources, shopping orientations and store attributes in both of formal wear and casual wear purchase. 2) Patronage behavior of department store in formal wear purchase was influenced by shopping activities, personal information sources, brand/store loyalty orientation. Regional store preference and store image attributes influenced the franchise store patronage behavior in formal wear purchase. Discount store patronage behavior in formal wear purchase was predicted by self-assurance/innovativeness and store image and service attributes. Information search of printed material/TV and store image and service attributes influenced off-price store patronage behavior for formal wear, while shopping activities and department store preference influenced off-price store patronage for casual wear. Traditional market patronage behavior for formal were was influenced only by brand/store loyalty, while traditional market patronage behavior for casual wear was influenced by sports activities, brand/store loyalty and price attributes.

• 한국소음진동공학회논문집
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• 제15권2호
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• pp.161-168
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• 2005

The absorbing material is mostly used to changing the acoustic energy to the heat energy in the passive control, and that consists of the porous media. That controls an air borne noise while the stiffened plates, damping material and additional mass control a structure borne noise. The additional mass can decrease the sound by mass effect and shift of natural frequency, and damping material can decrease the sound by damping effect. The passive acoustic control using these kinds of control materials has an advantage that is possible to control the acoustic in the wide frequency band and the whole space at a price as compared with the active control using the various electronic circuit and actuator. But the space efficiency decreased and the control ability isn't up to the active control. So it is necessary to maximize the control ability in the specific frequency to raise the capacity of passive control minimizing the diminution of space efficiency such an active control. Therefore, the characteristics of control materials and the optimum layout of control materials that attached to the boundary of structure-acoustic coupled cavity were studied using sequential optimization on this study.

• 한국관광식음료학회지:관광식음료경영연구
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• 제16권2호
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• pp.135-151
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• 2005

In accordance with changes in life style, people's desire to eat out is getting changed in their preferring factors from whether they can buy food they want to eat fast and easily to mood of the dining space, content and quality of service, hygiene condition of restaurant, quiet location and surrounding circumstance, and discount coupon and price destruction. In addition, consumers who begin to recognize the seriousness of environmental pollution prefer health-oriented food. On the other hand, excessive presence of competitors, growing personnel expense, increasing expenditure in accordance with swelling price of rent and material expenditure, increase of tax burden, decrease of income because of credit card service charge and high expected level by consumers make it difficult for restaurant's owners to manage restaurant business. Therefore, this study purposes to establish development of menu from the consumer's and the supplier's point of view and propose how to develop menu aiming at convenience, health and diversity.

• 한국식품저장유통학회지
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• 제7권2호
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• pp.160-165
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• 2000

The study aimed to review linerboard compositions of corrugated fiberboard boxes for Oriental melons(Cucumis melon L. var makuwa), analyzing relationships among material compositions, price, weight of boxes, theoretical compression and bursting strength of various liner boards. 19 and 22 different liner boards were currently used for the bleached and the unbleached corrugated boards, respectively. The corrugated board containers with the bleached liners were mostly used in the market although the average price was 10 percents higher than the unbleached. The average compression strength of the bleached. We strongly recommend to redesign the boxes because the average compression and bursting strength of the current boxes were much higher than national packaging standards as much as 70 and 82, respectively.

• Carbon letters
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• 제15권3호
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• pp.162-170
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• 2014

Pitch is an attractive raw material for carbon fiber precursors due to its low cost stemming from its availability as a residue of coking and petroleum processes. Ford Motor Company reported a carbon fiber target price of $11.0/kg by using a fast cycle-time manufacturing method with carbon fiber in an inexpensive format, allowing for an average retail price of gasoline of $3.58/gallon. They also recommended the use of carbon fiber with strength of 1700 MPa, modulus of 170 GPa, and 1.5% elongation. This study introduced a ca. $5.5{\mu}m$ carbon fiber with 2000 MPa tensile strength obtained from a precursor through simple distillation of petroleum residue. Petroleum pitch based carbon nanofibers prepared via electrospinning were characterized and potential applications were introduced on the basis of their large specific surface area and relatively high electrical conductivity.