• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.156-164
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• 1996

Tool interference is one of the most critical problems in machining die cavities and punches. When machining concave or convex regions of cavities with large radius tool in rough cutting, the tool easily overcuts or undercuts the portions of the surface, which result in machining inaccuracy. So the generation of interference-free tool path must be required for more efficient rough cutting. In this paper, we present a method for modeling die cavities which consist of simple surface or analytic compoyund surfaces and present an algorithm for checking and removing the tool interference occurred in machining the die cavities. Using these algorithms, we can represent a die cavity, and check the interfer- ence regions, and then remove these interferences. Especially we focus on the side interference in the sides of analytic elements and base surface boundary.

• Advances in concrete construction
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• v.4 no.3
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• pp.173-194
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• 2016

This paper consists in a study of a new contructive sequence of road viaducts with Movable Scaffolding System (MSS) using numerical tools based on finite element method (FEM). Traditional and new sequences are being used in Spain to build viaducts with MSS. The new sequence permits an easier construction of one span per week but implies some other issues related to the need of two prestressing stages per span. In order to improve the efficiency of the new sequence by reducing the number of prestressing stages per span, two solutions are suggested in this study. Results show that the best solution is to introduce the 100% of the prestressing force at the self-supporting core in order to improve the road viaduct construction with movable scaffolding system by reducing execution time without increasing economic costs.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.333-336
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• 1999

In this paper, a new high speed parallel input and parallel output GF(2$^{m}$ ) multiplier based on standard basis is proposed. The concept of the multiplication in standard basis coordinates gives an easier VLSI implementation than that of the dual basis. This proposed algorithm and method of implementation of the GF(2$^{m}$ ) multiplication are represented by two kinds of basic cells (which are the generalized and fixed basic cell), and the minimum critical path with pipelined operation. In the case of the generalized basic cell, the proposed multiplier is composed of $m^2$ basic cells where each cell has 2 two input AND gates, 2 two input XOR gates, and 2 one bit latches Specifically, we show that the proposed multiplier has smaller complexity than those proposed in 〔5〕.

• Journal of Korean Society for Quality Management
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• v.38 no.3
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• pp.378-390
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• 2010

From the perspective of employees working for public service agencies, we analyzed the causal relationship between service quality, relationship quality, design quality, customer satisfaction, and trust in public services. We conduct statistical analyses on the quality attributes we derived from a critical incident technique(CIT) analysis and build a measurement model, which has a second-order hierarchical structure. Survey data was collected from social work, childcare, and healthcare services. Using a structural equation modeling method, we identify a causal model and simultaneously estimate factor loadings and path coefficients. We find that all the quality dimensions are antecedents to satisfaction and then satisfaction precedes trust. The results show that service quality and design quality mediate in parallel the effect of relationship quality on satisfaction and both relationship and design qualities have stronger effects on satisfaction rather than service quality.

• Computers and Concrete
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• v.16 no.3
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• pp.381-397
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• 2015

Connections are the most important regions in a structural system especially for buildings in seismic zones. In R.C. structures due to large dimensions of members and lack of cognition of the stress distribution in a connection, reaching a comprehensive understanding of the connection behaviors becomes more complicated. The shear wall-to-floor slab connections in lateral load resisting systems have a potential weakness in transferring loads from slabs to shear walls which might change the path of load transformation to shear walls. This paper tries to investigate the effects of seismic load combinations on the behavior of slabs at their connection zones with the shear walls. These connection zones naturally are the most critical regions of the slabs in RC buildings. The investigation carried on in a simulated environment by considering three different structures with different shear wall layout. The final results of our study reveal that layout of shear walls in a building significantly affects the magnification of forces developed at the shear wall-floor slab connections.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.584-591
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• 2000

In distributed arithmetic-based architecture for an inner product between two length-N vectors, the size of the ROM increases exponentially with N. Moreover, the ROMs are generally the bottleneck of speed, especially when their size is large. In this paper, a ROM size reduction technique for DA( distributed arithmetic ) is proposed. The proposed method is based on modified OBC( offset binary coding) and control circuit reduction technique. by simulations, it is shown that the use of the proposed technique can result in reduction in the number of gates up to 50%.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.491-494
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• 2006

최근 국내에서도 IT 프로젝트 관리의 중요성이 대두 되고 있으나, 중소규모의 프로젝트를 관리 함에 있어서 PMBOK(Project Management Body Of Knowledge)의 프로젝트 관리 이론과 PERT/CPM(Program Evaluation and Review Technique/Critical Path Method)과 같은 관리 기법들을 이용한 효율적인 프로젝트 평가 및 관리 사례는 많지 않는 실정이다. 철저한 프로젝트 관리를 위해서 소요되는 추가적인 인적 및 시간적 자원에 대한 투자가 현실적으로 어려우며, 평가 기준이나 기법들이 너무 복잡하고 난해한 것이 주된 원인이라 생각된다. 이 논문은 이러한 현실적인 상황을 고려하여, 중소규모의 IT 프로젝트에 적용하기 쉬우면서 효율적으로 활용할 수있는 시간과 인적자원에 대한 일정 시뮬레이션 모델을 통해 프로젝트를 평가하는 정량적 기준을 제공하고 이를 통해 프로젝트의 성공적 완수를 돕는데 의의가 있다.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.101-110
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• 1998

In process planning for 3D pocket machining, the critical issues for the optimal process planning are the generation of cutting layers and the tool selection for each cutting layers as well as the other factors such as the determination of machining types, tool path, etc. This paper describes the optimal tool selection on a single cutting layer for 2D pocket machining, the generation of cutting layers for 3D pocket machining, the determination of the thickness of each cutting layers, the determination of the tool combinations for each cutting layers and also the development of an algorithm for determining the machining sequence which reduces the number of tool exchanges, which are based on the backward approach. The branch and bound method is applied to select the optimal tools for each cutting layer, and an algorithmic procedure is developed to determine the machining sequence consisting of the pairs of the cutting layers and cutting tools to be used in the same operation.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1118-1123
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• 2005

This paper proposes the CPM bar chart (CBC), a hybrid of the bar chart and the critical path method (CPM). The CBC overcomes shortages of the fence bar chart, while still retaining its advantages. The fence with direction is applied instead of the broken fence, which triggers considerable problems to identify and apply in the fenced bar chart. In addition, the notorious task to find dummy activities is no longer required. Upon the benefits of simplicity in the bar chart and logical work sequence in the CPM network, the CBC provides a relatively easy way to create and understand a schedule, thus improving communication quality between project participants.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.10
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• pp.427-436
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• 2013

In this paper, a method of moving path control of an automatic guided vehicle in an indoor environment through recognition of marker images using vision sensors is presented. The existing AGV moving control system using infrared-ray sensors and landmarks have faced at two critical problems. Since there are many windows in a crematorium, they are going to let in too much sunlight in the main hall which is the moving area of AGVs. Sunlight affects the correct recognition of landmarks due to refraction and/or reflection of sunlight. The second one is that a crematorium has a narrow indoor environment compared to typical industrial fields. Particularly when an AVG changes its direction to enter the designated furnace the information provided by guided sensors cannot be utilized to estimate its location because the rotating space is too narrow to get them. To resolve the occurrences of such circumstances that cannot access sensing data in a WSN environment, a relative distance from marker to an AGV will be used as fingerprinting used for location estimation. Compared to the existing fingerprinting method which uses RSS, our proposed method may result in a higher reliable estimation of location. Our experimental results show that the proposed method proves the correctness and applicability. In addition, our proposed approach will be applied to the AGV system in the crematorium so that it can transport a dead body safely from the loading place to its rightful destination.