• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1183-1192
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• 1993

Since the punching time is strongly related to the productivity in sheet metal stamping, there have been a lot of efforts to obtain the optimal tool path. However, most of the conventional efforts have the basic limitations to provide the global optimal solution because of the inherent difficulties of the NP hard combinatorial optimization problem. The existing methods search the optimal tool path with limiting tool changes to the minimal number, which proves not to be a global optimal solution. In this work, the turret rotation time is also considered in addition to the bed translation time of the NCT machine, and the total punching time is minimized by the simulated annealing algorithm. Some manufacturing constraints in punching sequences such as punching priority constraint and punching accuracy constraint are incorporated automatically in optimization, while several user-interactions to edit the final tool path are usually required in commercial systems.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.147-154
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• 1989

An effective placement of macro blocks having arbitrary width and height is very important in reducing the chip area and the signal delay. In this paper, we proposed a method of macro block placement to obtain the globally optimal placement using simulated annealing, and an efficient algorithm for eliminating the overlaps between the rectangular macro blocks which may remain even after the simulated annealing process is terminated. Each macro block was enlarged to take into account minimal routing area, and these macro blocks were compacted as much as possible during the placement. This procedure was implemented in C language running on MV10000/UNIX computer system, and good placements were obtained by applying this procedure to two circuits which were consisted of 50 and 160 macro blocks respectively. Several parameters giving great effects to final placements were investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.597-600
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• 2003

Bi-2223/Ag HTS wires have been fabricated by the PIT(powder in tube)process. Intermediate annealing was carried out to increase the homogenization and uniformity of the superconducting filaments embedded in the silver matrix during the deformation process that is important to sustain the engineering critical current density in long superconducting wire. Intermediate annealing act to release the deformation hardening of the superconducting wires during drawing process. Rolling parameters were investigated to roll the superconducting tapes with uniform thickness, width and winding tensions. Critical current of 60 m long superconducting tapes was measured 54.3 A continuously after final sintering heat treatment. The phase analysis of Bi-2223/Ag superconducting tapes are examined by the XRD.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.843-859
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• 2024

The university course scheduling problem (UCSP) aims at optimally arranging courses to corresponding rooms, faculties, students, and timeslots with constraints. Previously, the university staff solved this thorny problem by hand, which is very time-consuming and makes it easy to fall into chaos. Even some meta-heuristic algorithms are proposed to solve UCSP automatically, while most only utilize one single algorithm, so the scheduling results still need improvement. Besides, they lack an in-depth analysis of the inner algorithms. Therefore, this paper presents a novel and practical approach based on Tabu search and simulated annealing algorithms for solving USCP. Firstly, the initial solution of the UCSP instance is generated by one construction heuristic algorithm, the first fit algorithm. Secondly, we defined one union move selector to control the moves and provide diverse solutions from initial solutions, consisting of two changing move selectors. Thirdly, Tabu search and simulated annealing (SA) are combined to filter out unacceptable moves in a parallel mode. Then, the acceptable moves are selected by one adaptive decision algorithm, which is used as the next step to construct the final solving path. Benefits from the excellent design of the union move selector, parallel tabu search and SA, and adaptive decision algorithm, the proposed method could effectively solve UCSP since it fully uses Tabu and SA. We designed and tested the proposed algorithm in one real-world (PKNU-UCSP) and ten random UCSP instances. The experimental results confirmed its effectiveness. Besides, the in-depth analysis confirmed each component's effectiveness for solving UCSP.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.136-137
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• 2003

Recrystallization textures of ferritic stainless steel sheets of STS 430, the crystallographic texture was modified by means of cross rolling and subsequent annealing. The conventional normal rolling led to the formation of ｛334｝＜483＞ in the final recrystallization texture. Cross rolling in the present work was performed by a 45$^{\circ}$rotation of RD around ND. After recrystallization annealing the cross-rolled samples displayed stronger｛111｝//ND orientations. The cross rolled sample displayed a higher resistance against ridging.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.292-295
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• 1999

We investigated the effects of Pd impurities on cube-textures in cold rolled and recrystallized PtPd tapes The sample were made from Pt$_{1-x}Pd_x$ alloys (x from 0 to0.34) by rolling at low temperature. The thickness of the tapes were about 100 ${\mu}$m. The PtPd[111] pole figures of X-ray Diffraction for all the samples indicated similar deformed textures. But the recrystallized textures after annealing showed that a better cube texture was formed in the sample of larger x. The final textures were sensitive to annealing time and temperature when x was increased.

• Computational Structural Engineering
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• v.5 no.2
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• pp.93-104
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• 1992

The final objective of optimization methods is to find global optimum accurately and efficiently. The optmization processes by simulated annealing and genetic algorithm which have stochastic search process are examined and are applied to several mathematical models and truss, beam structures. Then the robustnesses of these two methods are studied and compared with the results of deterministic optimization methods from the viewpoints of reliability and running time in obtaining the global optimum.

• Journal of the Korean institute of surface engineering
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• v.26 no.3
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• pp.127-134
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• 1993

P+ and BF2+ were implanted to LPCVD amorphous silicon films deposited on thermally-oxidized silicon wafers and the low temperature annealing process followed with various conditions to activate implanted ions and to recrystallize the films. We tried to find the optimum processing condition by comparing the recrystallization behaviors and the electrical properties. TEM analysis showed that the final grain size of BF2+-implanted films was similar to that of unimplanted films, whereas the grains of P+-implanted films. For both P+ - and BF2+ -implanted films, sheet resistances were decreased with elevating annealing temperature and the minimum value was about 110~120$\Omega$/$\square$ at $600^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.382-389
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• 2019

A novel folding process is proposed using a repeated cold-die forging and annealing to form a sterling silver ring. Sterling silver plate was cut into a doughnut shape, and lattices with 0.43-mm line-width were imprinted on it. The sample was folded by forging using dies with slopes of $45^{\circ}$, $60^{\circ}$, and $75^{\circ}$ and annealing. For comparison, samples were also fabricated without annealing. Strain was identified by measuring the length of lattices. Vernier calipers, a Vickers hardness tester, an optical microscope, and a UV-VIS colorimeter were used to determine the size, hardness, microstructure, and body color. Without annealing, cracks occurred. However, successful deformation was possible when annealing was used. The results of macro strain measurements show that the outer diameter and width decreased, while the inner diameter and thickness increased after the final process. The maximum strain was increased 0.128 toward the parallel direction. The Vickers hardness decreased after annealing and increased after the folding process. The microstructure results showed that the grain size increased after annealing but decreased after folding. The color difference based on the Lab index was under 10 for all processes. Eventually, a doughnut-shaped silver plate was successfully deformed into a ring shape by the folding process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.2
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• pp.87-97
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• 1999

This study is concerned with developing a hybrid heuristic algorithm for solving the redundancy optimization problem which is very important in system safety, This study develops a HH(Hybrid Heuristic) method combined with two strategies to alleviate the risks of being trapped at a local optimum. One of them is to construct the populations of the initial solutions randomly. The other is the additional search with SA(Simulated Annealing) method in final step. Computational results indicate that HH performs consistently better than the KY method proposed in Kim[8]. Therefore, the proposed HH is believed to an attractive to other heuristic methods.