• 한국CDE학회논문집
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• 제3권4호
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• pp.223-235
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• 1998

A dedicated CAM(Computer-Aided Manufacturing) system has been developed, which generated tool-path to machine Styrofoam stamping die-patterns in Chrysler Corporation. A previous process to build die-patterns was to "stick build" the pattern, in which stock is cut & glued together, and then the NC machining of part-surface shape completes building a Styrofoam die-pattern. The current process utilizes the developed CAM system, and almost removes the manual work, consequently reduces the overall lead time. The paper presents the overall system structures, tool-path generation, and some features of Styrofoam pattern machining.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.659-663
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• 2005

기존의 디자인패턴도구에서는 디자인패턴을 정형화된 방법으로 표현하고 설계할 수 없었으므로, 설계정보에 디자인패턴이 재사용 될 때 중복적으로 설계정보가 표현되었다. 그리고 정형화된 디자인패턴은 설계자의 의도에 맞도록 확장 가능하여야 하며, 설계자의 설계의도에 따라 객체를 표현할 수 있어야 한다. 따라서 본 논문에서는 디자인패턴을 정형화하기 위한 메타모델로 XMI를 이용하여 정의하는 방법과 메타모델로 표현된 디자인패턴을 확장하기 위한 메타모델을 표현할 수 있도록 하였다.

• 한국표면공학회지
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• 제32권3호
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• pp.289-296
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• 1999

The integration of the LSI has been greatly improved and the circuit patters on the LSI are becoming finer line and pitch. The high-density electronic packaging technology is improved. In order to realize the high-density packaging technology, the density of the circuit wiring of the printed circuit boards have also been more dense. The build-up process multilayer printed circuit board technology have a lot of vias, possibilities of the finer conductor wirings and have a freedom of capabilities of wiring design. The build-up process printed circuit boards have the wiring rules which are the pattern width: $100-20\mu\textrm{m}$, the via hole diameter: $100-50\mu\textrm{m}$. There three kinds of build-up processes as far materials and hole drilling. In this paper, the recent technology trends of the build-up printed circuit board technologies are described.

• 한국CDE학회논문집
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• 제6권4호
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• pp.263-270
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• 2001

In stamping-die manufacturing, the first step is to build die patterns for lost wax casting process. A recent industry trend is to manufacture the die pattern using 3-axis NC machining. This study identifies technical considerations of the pattern machining caused by the characteristics of Styrofoam material, and proposes technical methods related to establishing a process plan and generating tool paths for optimizing the pattern machining. In this paper, the process plan includes the fellowing three items: 1) deter-mining a global machining sequence-a sequence of profile, top, bottom machining and two set-ups, 2) extracting machining features from a pattern model and merging them, and 3) determining a machining sequence of machining features. To each machining feature, this study determines the machining start point, generates the approach tool path, and proposes a tool path linking method fur reducing the distance of the cutter rapid motion. Finally, a smooth tool path generation and an automatic feedrate adjustment (AFA) method are introduced far raising the machining efficiency.

• 한국정밀공학회지
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• 제18권3호
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• pp.47-52
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• 2001

Rapid Prototyping(RP) has been widely applied in designing and developing process of new products. RP can reduce the lead time and expense required to bring a new product form initial concept to production. Among several RP process can dramatically reduce the total build time and be applied for fabrication of large-sized and free form object because it uses in LOM the paper thickness is 0.05∼0.38mm as deposition feature segment. In this study, mechanical properties of pattern with LOM system is studied for optimal design of sand mold casting. The main result is that tensile, compressive strength and pattern size are significantly affected by temperature of hot roll.

• 한국CDE학회논문집
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• 제11권3호
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• pp.223-233
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• 2006

Layered manufacturing(LM) is emerging as a new technology that enables the fabrication of three dimensional heterogeneous objects such as Multi-materials and Functionally Gradient Materials (FGMs). Among various types of heterogeneous objects, more attention has recently paid on the fabrication of FGMs because of their potentials in engineering applications. The necessary steps for LM fabrication of FGMs include representation and process planning of material information inside an FGM. This paper introduces a new process planning algorithm that takes into account the processing of material information. The detailed tasks are discretization (i.e., decomposition-based approximation of volume fraction), orientation (build direction selection), and adaptive slicing of heterogeneous objects. In particular, this paper focuses on the discretization process that converts all of the material information inside an FGM into material features like geometric features. It is thus possible to choose an optimal build direction among various pre-selected ones by approximately estimating build time. This is because total build time depends on the complexity of features. This discretization process also allows adaptive slicing of heterogeneous objects to minimize surface finish and material composition error. In addition, tool path planning can be simplified into fill pattern generation. Specific examples are shown to illustrate the overall procedure.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권8호
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• pp.555-564
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• 2002

디자인 패턴은 과거에 잘 정의된 설계정보를 활용하기 위한 목적으로 사용되어진다. 이러한 디자인 패턴의 활용은 객체지향 패러다임에서 재사용성과 개발시간의 단축 그리고 소프트웨어 품질의 향상을 가져온다. 그러나 이러한 디자인 패턴의 광범위한 활용에도 불구하고 대부분의 디자인 패턴 정보는 수작업에 의해 활용됨으로써 일관성이 없고 활용능력이 떨어진다. 또한 설계자에 의해 적용된 디자인 패턴정보는 소프트웨어에서 나타나지 않기 때문에 디자인 패턴에 대한 추적성에 대한 문제를 가진다. 이에 본 논문에서는 디자인 패턴지향 소프트웨어 개발 지원 도구를 제시한다. 이 시스템은 디자인 패턴의 관리와 소프트웨어 설계 및 자동화 소스코드 생성기능을 지원한다. 디자인 패턴 관리 기능은 존재하는 디자인 패턴을 저장관리 및 분석과 새로운 디자인 패턴 등록할 수 있는 기능을 담고 있으며, 소프트웨어 설계 기능은 UML 형태의 소프트웨어 설계기능과 디자인 패턴요소의 자동생성기능을 지원한다. 또한 이러한 설계정보를 이용한 소스코드 자동생성기능을 지원하는 소스코드 관리 기능을 가진다. 그 결과 기존의 CASE 도구에서 제시하지 못한 디자인 패턴요소의 추적성을 설계정보에 포함시킴으로서 소프트웨어 분석의 용이성을 제공하고 디자인 패턴 관리와 자동 소스코드 생성기능의 제공을 통해 보다 안정되고 효율적인 시스템을 구축할 수 있다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.11-17
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• 2022

Design-bid-build (DBB) is the most common project delivery method among highway projects. State Highway Agencies (SHAs) usually apply a low-bid approach to select contractors for their DBB projects. In this approach, the Federal Highway Agency suggests SHAs heighten contractors' competition to lower bid prices. However, these attempts may become ineffective due to collusive bidding arrangements among certain contractors. One common strategy is the rotation of winning bidders of a group of contractors who bid on many of the same projects. These arrangements may also be specific to a particular region or vary in time. Despite the practices' adverse effects on bidding outcomes, an effective model to detect red-flag bidding patterns is lacking. This study fills the gap by proposing a novel framework that utilizes pattern mining techniques and statistical tests for unusual pattern detection. A case study with historical data from an SHA is conducted to illustrate the proposed framework.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 3rd Korea-Japan Advanced Semiconductor Packaging Technology Seminar
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• pp.183-192
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• 2001

1- Buildup PCB technology is utilized to a bare chip attach substrate technology for packaging of semiconductor chip 2- Requirement for the substrate design rule is described in SIA International Technology Roadmap for Semiconductor. 3- There are seven fabrication methods of build-up technology. 4- Coating and lamination for resin and photo, and laser for micro via hope processes are available. Below $50\mu\textrm{m}$ in diameter is possible. 5- Fine pitch lines down to $30\mu\textrm{m}$ can be achieved by pattern plating with better electrical property. 6- Dielectric loss reduction is a key material improvement item for next generation build-up technology. 7- High band width up to 512 GB/s is possible with current wiring groundrule.

• 한국정보통신학회논문지
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• 제11권3호
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• pp.500-506
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• 2007

Type Object 디자인 패턴은 하나의 클래스가 수많은 하위 클래스를 갖거나, 그 하위 클래스의 개수를 소프트웨어 개발시에 예측할 수 없는 상황을 해결하고자 제시된 패턴이다. 그러나, 이 패턴은 적용력과 여러 장점에도 불구하고 인스턴스를 생성하는 클래스와 그 인스턴스의 실제적 클래스가 분리되어 있고 또한 객체 레퍼런스에 의해서 서로 연관되어 있으므로 이에 대한 관리를 위한 메커니즘과 패턴의 이해에 있어서 많은 복잡성을 갖는 문제점이 있다. 본 논문에서는 이러한 문제를 해결하기 위한 Type Object Class의 설계와 구현을 제시한다. 즉, Type Object 패턴의 Type Class와 Object Class로부터 Type Object Class를 설정하고, 이를 런타임에 생성되고 사용되게 함으로써, 인스턴스들이 객체 지향프로그래밍 언어에서 제공하는 고유의 클래스를 참조하게 되어 별도의 클래스 참조 메커니즘을 가질 필요가 없도록 하였다. 따라서, 별도의 클래스 참조 메커니즘을 개발하는 부담과 이 메커니즘의 동작으로 인한 실행 상의 성능 저하의 문제가 개선되는 효과가 있다.