• Applied Microscopy
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• v.45 no.4
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• pp.208-213
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• 2015

Nanomanipulators installed in focused ion beam (FIB), which is used in the lift-out of lamella when preparing transmission electron microscopy specimens, have recently been employed for electrical resistance measurements, tensile and compression tests, and in situ reactions. During the pick-up process of a single nanowire (NW), there are crucial problems such as Pt, C and Ga contaminations, damage by ion beam, and adhesion force by electrostatic attraction and residual solvent. On the other hand, many empirical techniques should be considered for successful pick-up process, because NWs have the diverse size, shape, and angle on the growth substrate. The most important one in the in-situ precedence, therefore, is to select the optimum pick-up process of a single NW. Here we provide the advanced methodologies when manipulating NWs for in-situ mechanical and electrical measurements in FIB.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1235-1238
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• 1998

In television stereo system, to produce the sound image for spatial impression is too difficult because of the narrow distence between two speakers. A method of widening the sound image using precedence effect was introduced but it didn't work effectively in low frequency band. In this paper, we propose a new method to produce an expanded sound image in full band of audio requency in band sound is expanded by phase shifting method and a higher frequency band sound is expanded by reflection. In simulation and experiment, the proposed system guarantees useful effect of sound image expansion in television stereo system.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1227-1230
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• 1998

Phase control methods are used to expand the sound image in general AV system. However, these methods are effective only to the signal under 1kHz, and the listener must be located in front center of the speaker system. In this paper, we realize the realtime processing system in which phase shifting method is dominant at low frequency and precedence effect is dominant at high frequency. Two sound cards are used to process the audio signal in realtime with 16 bits stereo channel of 44.1 kHz sampling frequency. And the analog circuit is designed to process the phase shifting. In experiments the usefulness of the proposed stereo system is confirmed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.828-831
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• 2005

In feature-based multi-resolution modeling, the features are rearranged according to a criterion for the levels of detail (LOD) of multi-resolution models. In this paper, two different LOD criteria are investigated and discussed. The one is the volumes of subtractive features, together with the precedence of additive features over subtractive features. The other is the volumes of features, regardless of whether the feature types are subtractive or additive. In addition, the algorithms to define and extract the LOD models based on the criteria are also described. The criterion of the volumes of features can be used for a wide range of applications in CAD and CAE in virtue of its generality.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.517-522
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• 2005

This paper addresses scheduling heuristics for an assembly job-shop that includes at least an assembly process throughout its processes. The assembly job shop has certain characteristics not only considering the precedence relationship between the processes but also considering the processing progress between the parts. In addition, it probably presents a different processing time for the same product according to the order of processes and the point of workable time, due to the difference in the availability of equipments. The paper proposes several priority-based dispatching rules that consider these characteristics of the assembly job-shop, aiming to minimize the total tardiness of products in the shop floor. Computational tests showed that job due date based priority rules significantly outperform existing priority rules in terms of total tardiness.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.118-118
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• 1993

We consider a discrete event dynamic system called periodic job shop, where an identical mixture of items called minimal part set(MPS) is repetitively produced in the same processing order and the primary performance measure is the cycle time. The precedence relationships among events(starts of operations) are represented by a directed graph with rocurront otructure. When each operation starts as soon as all its preceding operations complete(called earliest starting), the occurrences of events are modeled in a linear system using a special algebra called minimax algebra. By investigating the eigenvalues and the eigenvectors, we develop conditions on the directed graph for which a stable steady state or a finite eigenvector exists. We demonstrate that each finite eigenvector, characterized as a finite linear combination of a class of eigenvalue, is the minimum among all the feasible schedules and an identical schedule pattern repeats every MPS. We develop an efficient algorithm to find a schedule among such schedules that minimizes a secondary performance measure related to work-in-process inventory. As a by-product of the linear system approach, we also propose a way of characterizing stable steady states of a class of discrete event dynamic systems.

• Journal of Ocean Engineering and Technology
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• v.17 no.1
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• pp.67-71
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• 2003

This paper presents the use of an evert system to automate process planning of block assembly, a task that is usually completed manually. In order to determine the sequence of assembly operation, a search method guided by rules, such as merging of related operations, grouping of similar operations, and precedence rules based on know-hows and geometrical reasoning, is used. In this paper, the expert system developed is explained in detail regarding a global database, control strategies, and rule bases. For verification purposes, the evert system has been applied to simple examples. Since the rule bases are isolated from the inference engine in the developed system, it is easy to add more rules in the future.

• The Korean Journal of Financial Studies
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• v.9 no.1
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• pp.221-244
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• 2003

This study is aimed to investigate the effects of foreign exchange rates on stock market returns. For the United States, the United Kingdom, Germany, Japan and Korea, the cross-correlation precedence of foreign exchange rate on stock market is found in the case of Germany and Korea. But that of stock market is not observed in any case. We performed three kinds of causality and exogeneity test of Granger test, Sims test and Geweke-Meese-Dent test. The analyses on the full period show the time-lag causal, exogeneous relation of foreign exchange rates with Granger, Sims and GMD test for Korea. The United Kingdom presents the significance with Granger and Sims test while Germany reveals the time-lag relation with Granger and GMD test. When we divide the period into two parts with the Louvre Accord, the first part give the less degree of time-lag relation. But in the second period the three kinds of causality and exogeneity test propose consistent time-lag relation with foreign exchange rates on stock markets for the United Kingdom and Korea with the three test methods. And Granger's test prove German foreign exchange market have a time-lag relation on stock market.

• IE interfaces
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• v.13 no.3
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• pp.512-520
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• 2000

An integrated process planning and scheduling model considering outsourcing in manufacturing supply chain is proposed in this paper. The process planning and scheduling considering outsourcing are actually interrelated and should be solved simultaneously. The proposed model considers the alternative process plans for job types, precedence constraints of job operations, due date of production, transportation time and production information for outsourcing. The integrated states include:(1) Operations sequencing, (2) Machine selection, (3) Scheduling with outsourcing under the due date. To solve the model, a heuristic approach based on genetic algorithm(GA) is developed. The proposed approach minimizes the makespan considering outsourcing and shows the best operation-sequences and schedule of all jobs.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.2
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• pp.45-55
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• 1989

This paper deals with development of a computer-aided process selection and sequencing technique and its software for metal cutting processes of rotational parts. The process selection procedure consists of selection for proper machining operations and machine tools suitable for the selected operations. Machining operations are selected based on machining surface features and machine tools are selected by employing a conversion table which converts machining operations into machine tools. The process sequence is determined by the proper manipulation of the precedence relation matrix. A computer program for the proposed technique is developed by using Turbo-Pascal on IBM PC/AT compatible system. The proposed technique works well to real problems.