• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.634-640
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• 2009

The plate manufacturing processes are composed of the reheating furnace, finishing mill, cooling process and hot leveling. The finishing rolling mill (FM) as a reversing mill has produced the plate steel through multiple pass rolling. The automatic gauge control (AGC) is employed to maintain the thickness tolerance. The high grade products are forming greater parts of the manufacturing and customers are requiring strict thickness margin. For this reason, the advanced AGC method is required instead of the conventional AGC based on the PI control. To overcome the slow response performance of the conventional AGC and the thickness measurement delay, a fuzzy AGC based on the thickness deviation and its trend is proposed in this paper. An embedded controller with the fuzzy AGC has been developed and implemented at the plate mill in POSCO. The fuzzy AGC has dynamically controlled the roll gap in real time with the programmable logic controller (PLC). On line tests have been performed for the general and TMCP products. As the results, the thickness deviation range (maximum - minimum of the inner plate) is averagely from 0.3 to 0.1 mm over the full length. The fuzzy AGC has improved thickness deviation and completely satisfied customer needs.

• 지능정보연구
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• 제8권2호
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• pp.37-49
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• 2002

우리 나라 중소기업의 지식경영 수준을 비교 평가하기 위하여 150개 업체를 대상으로 설문 조사하였다. 연구 모형은 1) 지식경영과 기업전략 2) 지식경영 문화와 체계 3) 지식경영을 위한 학습 과정과 공유 4) 지식경영을 위한 정보기술 5)지식경영 성과측정과 보상에 대하여 평가하였다. 연구 결과로는 기업의 특성에 따라 지식경영 수준 차이가 있다는 것이다. 특히, 우리 나라 기업에서 지식경영을 위한 기업 문화 형성이 미흡하며, 지식경영을 위한 학습 과정과 성과측정 및 보상이 다른 영역에 비해 상대적으로 낮게 나타났다. 우리 나라 기업의 특성을 맞는 지식경영의 평가 개발이 요구된다.

• 한국전자통신학회논문지
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• 제11권4호
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• pp.387-394
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• 2016

현재 운영되고 있는 제철소의 열연 공장은 24시간 상시 운전을 하고 있다. 각 공정별 주요 기능을 살펴보면 가열로, 조압연, 사상압연 및 권취 등으로 구성되어있으며, 여기에서 두께 및 폭 압연을 하고 이를 위한 소재의 온도를 조절하는데 큰 기능이 있다. 여기에는 작업의 특성상 고장 및 불량 요소가 상당히 많다. 또한 제품의 출하 이후에도 클레임이 발생하면 조사가 필요한 실정이다. 기존의 각 공정별 두께계, 폭계, 온도계에서의 독립적인 데이터 취득 및 모니터링에 의한 운전은 조업자로 하여금 많은 피로감을 준다. 이를 보완하고자 각 공정의 데이터를 통합해서 기능별로 모니터링하고 향후 작업 결과도 확인할 수 있는 통합 모니터링 시스템의 필요성이 대두되었다. 이에 압연공정 품질모니터링 시스템을 개발함으로서 보다 효율적인 운영이 가능하게 될 것으로 기대한다.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1999년도 제16회 동계학술발표회 논문집
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• pp.281-295
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• 1999

This paper analyses the effects of the increase of logistics outsourcing on the economy which are largely classified into three parts. The firm level and industry level are two among them which will be summarized below. The another is consumers level. On the fm level, the logistics outsourcing of a manufacturing firm not only helps to increase the efficiency of itself and but also confront the competitive environments by weakening the entry barriers, i.e., the emergence of contestable market. The reasons why the efficiency of the firm enhances are also largely divided into two parts. One is due to the reduction of inventory cost by replacing it by the information cost resulting from internet use. The other is owing to reducing the life cycle of production process by the emergence of virtual enterprises which are located in one point in De process of supply chain management. The weakening of entry barriers is directly affected by the drastic increase of internet users in twofold reasons: one is based on the restricted competitive characteristics due to the long-term transaction relationship between logistics providers and the companies who offer logistics services and the other, due to the weakening of the restriction of space and time. The effect of industry level is due to the transition of traditional to virtual vertical integration system The firms corresponding to a connection point in the process of supply chain management would try to realize both the scale of economy and the scope of economy for strengthening the competitiveness. We indicated above the emergence of contestable market however, it is a short-term phenomenon and result in the oligopoly market due to the entry barriers in the long-run sense.

• 한국분말재료학회지
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• 제29권1호
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• pp.34-40
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• 2022

Recently, high-entropy carbides have attracted considerable attention owing to their excellent physical and chemical properties such as high hardness, fracture toughness, and conductivity. However, as an emerging class of novel materials, the synthesis methods, performance, and applications of high-entropy carbides have ample scope for further development. In this study, equiatomic (Hf-Ti-Ta-Zr-Nb)C high-entropy carbide powders have been prepared by an ultrahigh-energy ball-milling (UHEBM) process with different milling times (1, 5, 15, 30, and 60 min). Further, their refinement behavior and high-entropy synthesis potential have been investigated. With an increase in the milling time, the particle size rapidly reduces (under sub-micrometer size) and homogeneous mixing of the prepared powder is observed. The distortions in the crystal lattice, which occur as a result of the refinement process and the multicomponent effect, are found to improve the sintering, thereby notably enhancing the formation of a single-phase solid solution (high-entropy). Herein, we present a procedure for the bulk synthesis of highly pure, dense, and uniform FCC single-phase (Fm3m crystal structure) (Hf-Ti-Ta-Zr-Nb)C high-entropy carbide using a milling time of 60 min and a sintering temperature of 1,600℃.

• 지능정보연구
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• 제13권3호
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• pp.63-82
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• 2007

본 논문에서는 유연제조시스템(FMS)에서 다단계스케줄링 문제를 효율적으로 해결하기 위한 적응형 혼합유전 알고리즘(ahGA) 접근법을 제안한다. 제안된 ahGA는 FMS의 해를 개선시키기 위하여 이웃탐색기법을 사용하며, 유전탐색과정에서의 수행도를 향상시키기 위해 유전알고리즘(GA)의 파라메터들을 조정하기 위한 적응형 구조를 사용한다. 수치실험에서는 제안된 ahGA와 기존의 알고리즘들 간의 수행도를 비교하기 위하여 두가지형태의 다단계스케줄링문제를 제시한다. 실험결과는 제안된 ahGA가 기존의 알고리즘들 보나 더 뛰어난 수행도를 보여주고 있다.

• 소성∙가공
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• 제25권1호
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• pp.43-48
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• 2016

H-beams are generally produced by hot rolling composed of a Break Down Mill (BDM) and a Finishing Mill (FM). The goal of the current study was to develop BDM rolling of H300ｘ300 beams from blooms slit from slabs. In order to manufacture H300ｘ300 beams, the caliber design and the pass schedule of BDM rolling were proposed for a bloom instead of a beam blank. The proposed BDM caliber design and pass schedule were tested using FE-simulation and pilot tests. For the major shape dimensions, such as flange width, web height, web thickness, as well as BDM rolling loads, a comparative analysis between the FE-simulation and the pilot rolling tests was conducted. The results of FEM analysis and pilot rolling tests showed good consistency. Moreover, BDM rolling loads were predicted to be in the range of allowable rolling loads. It was concluded that the designed BDM rolling is suitable for implementation within current manufacturing capacity.

• 기술혁신연구
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• 제14권2호
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• pp.29-48
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• 2006

This paper analyzes organizational behavior of an established firm when disruptive innovation, a change in product architecture, occurs on a previous product. For the analysis, the paper analyzes and compares the behavior of an established fm through product trajectories between NEC (an established firm) and Toshiba (a new entrance) in the Japanese laptop computers industry. An established firm that has developed and produced a previous product is difficult in adapting to a disruptive innovation due to accumulated immense knowledge through a previous product. By using regression model in the product trajectory analysis, the paper analyzes the behavior of established firms. Product trajectory means a pattern of product strategy shown in a series of products. Two facts found in the paper are as follows. First, though NEC was able to develop a laptop computer at the same time with Toshiba, it was restricted by the resources of a previous product in the early stage. Second, possibility of teaming trap in the adapting process was found. The paper found the risk that too much commitment in one evolution stage would prohibit the adapting behavior in the next evolution stage.

• 한국CDE학회논문집
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• 제21권3호
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• pp.313-324
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• 2016

As building information modeling (BIM) is expanding its influence in various fields of architecture, engineering, construction and facility management (AEC-FM) industry, BIM-based automated code compliance checking has become possible prospects. For the automated code compliance checking, requirements in building code need to be processed into explicit representation that enables automated reasoning. This paper aims to develop high-level methods that translate verb phrases into explicit representation. The high-level methods represent conditions, properties, and related actions of the building objects and clarify the core content of the constraints. The authors analyze building permit requirements in Korea Building Code and establish a standardized process of deriving the high-level methods. As a result, 60 kinds of the high-level methods were derived. In addition, method classification, analysis, and application are introduced. This study will contribute to the representation of explicit building code sentences and establishment of the automated building permit system of Korea.

• 한국세라믹학회지
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• 제41권11호
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• pp.819-825
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• 2004

광학 현미경을 사용한 시멘트 클링커의 특성 분석은 시멘트의 품질뿐만 아니라 제조공정도 예측 평가할 수 있다. 그러므로 본 연구에서는 광학 현미경(반사)으로 소성 조건을 달리한 클링커의 특성을 분석하였다. 승온 및 냉각 속도가 느려짐에 따라 alite와 belite는 성장하였으며, 특히 냉각 속도는 belite의 성장에 큰 영향을 주었다. 또한 최대 소성 온도에서의 유지 시간이 20분 증가함에 따라 alite와 belite가 약 5fm정도 성장하는 것을 확인하였으며, 최대 소성 온도가 140$0^{\circ}C$인 경우, belite의 크기는 양호하나 alite는 제대로 성장하지 않은 10～15$\mu\textrm{m}$수준이었다.