Earticle

In this work, rapid prototyping and three-dimensional finite element analysis are simultaneously applied to the die design of metal forming processes. Rapid prototyping is a new prototyping technology which produces three-dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus(SLA), which is the most widely used rapidprototyping system, is introduced to manufacture the die set. For general preparation of STL file, which is the standard input file of rapid prototyping system, mesh data which are used in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are dffectively connected. A die set for spider forging and a clover punch for deep drawing section are manufactured effciently using SLA prototypes, and metal forming experiments are carried out using them. Comparing the result of experiments with that of analyses, the processes can be predicted and designed successfully.

최근 들어 소프트웨어 시스템은 점차적으로 복잡해지고 있으며, 고객(customer)은 보다 빠른 개발을 요구하고 있다. 전통적인(traditional) 순차적 접근법 (Sequential Approach)으로는 이러한 압력에 효과적으로 대처할 수 없어 대안으로 반복적 접근법 (Iterative Approach)이 적용되고 있다. 대표적인 반복적 접근법으로는 래쇼날의 단일화된 프로세스 (Rational Unified Process, RUP)가 있다. 그러나 RUP의 표준화된 수행방법은 단계, 반복과 활동들을 모두 순차적으로 수행하는 형태이다. 그 결과, 하나의 반복에서 수행된 하나의 활동은 다음 반복의 해당 활동이 수행될 때까지 기다려야 하는 인력낭비 현상이 발생한다. RUP를 수행하는 방법으로는 선형 접근법, 순차적 접근법, 중첩된 반복 접근법과 Time-boxed 반복 접근법이 제안되었다. 그러나 이들 방법은 인력낭비 현상 또는 적용시 프로젝트 관리의 어려움이라는 문제점을 갖고 있다. 본 논문은 활동들을 동시에 수행하는 방법을 제안하였다. 동시개발 접근법은 인력낭비 현상을 방지할 수 있으며, 프로젝트 관리의 어려움도 해결할 수 있는 장점을 갖고 있다.

Recently, the software system is getting complicating and the customers are requiring faster development. For the traditional sequential approach can't against this problem iterative approach is used instead. For the representative iterative approach, there is RUP (Rational's Unified Process). However, RUP standard practical methods are phase, iteration, and disciplines, sequentially. As a result, there's some waste of manpower when a discipline is executed in an iteration, it has to wait till the next same discipline is executed. There are linear approach, sequential approach, overlapped iteration approach, and time-boxed iteration for the efficient execution of RUP. However, they have some problems such as waste of manpower or difficulty in the project management. This paper suggests a method about how to execute the disciplines as a concurrent type. The concurrent approach prevents the waste of manpower and solves the difficulty of project management.

We propose a dynamic slicing algorithm to compute the slice of concurrent aspect-oriented programs. We use a dependence based intermediate program representation called Concurrent Aspect-oriented System Dependence Graph (CASDG) to represent a concurrent aspect-oriented program. The CASDG of an aspect-oriented program consists of a system dependence graph (SDG) for the non-aspect code, a group of dependence graphs for aspect code and some additional dependence edges used to connect the system dependence graph for the non-aspect code to dependence graph for aspect code. The proposed dynamic slicing al-gorithm is an extended version of NMDS algorithm for concurrent object-oriented programs, which is based on marking and unmarking of the executed nodes in CASDG appropriately during run-time.

The inherent limitations of mobile environments like disconnections, mobility, bandwidth etc affects the performance of system when several mobile clients access the shared data items at the same time. Several timeout based strategies are implemented in literature to deal with the starvation of data items during disconnections and mobility. This increases the abort and rollback rates. In the proposed heuristic approach, the time for execution of a transaction can be predicted based on the given timer value for a specific mobile client. The simulation results show the time for execution can be dynamically estimated given the timer value and vice versa for a particular request originating from specific mobile clients. This increases the throughput of the system as compared to the timer based strategies proposed in the literature.

DJ정부와 노무현 정부는 북한에 당근을 먼저 제공하고 채찍 사용의 필요가 없어지기를 기대하였다. 현 MB 정부는 “비핵 개방3000”에서 표현되듯이 핵폐기 요구라는 채찍을 앞세우고 북한이 긍정적으로 반응하면 당근을 제공하겠다는 정책을 취해다. 그러나 북한은 당근에 감사하는 정권이 아니였고 채찍에 굴복하는 정권도 아니였다. 따라서 본고에서는 당근과 채찍을 동시적으로 사용해야 상대방의 행동을 변화시키기에 효과적이며, 그 사용수단을 선별적으로 배합해야 효과적인 대북전략이 될 수 있다는 점을 논증하고자 했다. 남북교역을 막아서 경제적인 채찍으로 사용하더라도 북한에 우리의 침투력을 강화시키는 개성공단은 확대 발전시켜서 당근으로 사용하자는 것이다. 전략상 여러 곳을 봉쇄하면 한 곳을 출구로 유도하는 것이 합리적이다. 그리고 위에 묘사한 것처럼 현 정부의 대북정책이 크게 보면 당근과 채찍을 동시에 사용하는 투 트랙 전략의 범주에 속하기는 하지만 대북전략의 틀을 “선별적-동시적인 투 트랙 대북전략”으로 구체화 시키면서 당근에 해당되는 개성공단을 적극적으로 확대발전시키는 전략으로 일부 수정을 하자는 것이다.

The two previous government provided 'carrot' for the North Korea in advance, while current MB government suggested 'whip' for the North Korea in advance to carrot as named 'Non-nuclear and then Open-door 3000$' policy. However the North Korea maintained provocative military attacks toward Korea during two former and current regimes. To enhance effectiveness of strategy toward North Korea and to change their behavior, hence, I propose 'the strategically selective and concurrent two track approach of carrot & whip' toward North Korea. As for the criteria to select the means toward the North Korea, I suggest the mean to weaken North Korea & to strengthen South Korea. In conclusion, we can lead and induce North Korea to open-door policy if we invest and develop more and more Gae Sung Industrial Complex in North Korea to penetrate into the peoples there economically and culturally, while we prohibit trades between North & South Korea to undermine North Korean regime economically , and defense against North Korea's military attacks determinately.

Engineering design involves the specification of many variables that define a product, how it is made, and how it behaves. Before some variables can be determined, other variables must first be known or assumed. This fact implies a precedence order of the variables, and of the tasks of determining these variable consequently. Moreover, design of complex systems may involve a large number of design activities. In this paper, the activity-activity incidence matrix is considered as a representation of design activity analysis which mainly focuses on the precedence constraint. In order to analyze the activity-activity incidence matrix, a heuristic algorithm is proposed, which transforms an activity-activity, parameter-formula, and parameter-parameter incidence matrix into a lower triangular form. The analysis of the structured matrices can not only significantly reduce the overall project complexity by reorganizing few critical tasks in practice, but also aims at obtaining shorter times considering the solution structure by exploring concurrency.

Unilateral presentation of vestibular schwannoma with concurrent chronic middle ear diseaseor cholesteatoma is rare. We report a series of patients with ipsilateral chronic middle ear diseaseand vestibular schwannoma, which were simultaneously removed via the enlarged translabyrinthineapproach. All tumors were near-totally removed, and middle ear disease wascompletely excised; there were no major postoperative complications such as cerebrospinalfluid leakage, cholesteatoma recurrence, or meningitis. If hearing preservation of the affectedear is not necessary, simultaneous surgical removal of both pathologies is more convenientthan staged treatment. The enlarged translabyrinthine approach can achieve complete treatmentwith one corridor.