• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1273-1278
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• 2012

In this paper, we introduce modified integer transforms for lossless image compression and evaluate their performances for two-dimensional transforms. The two-dimensional extensions of the modified integer transforms show different performances in terms of coding efficiency and computational complexity. Thus, we measure performances for two-dimensional separable transforms and a two-dimensional non-separable transform. The separable modified integer transform used in H.264, the modified integer transform using the lifting scheme, and the non-separable transform in JPEG XR are evaluated in this paper. Also, experiments and their results are given. The experimental results indicate that the modified integer transform using the lifting scheme shows the best performance in terms of compression efficiency.

• International Journal of Contents
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• v.7 no.1
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• pp.58-64
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• 2011

This paper is concerned with simulation exercises used to train key response agencies for crisis situations. While 'multi-agency' simulations are increasingly acknowledged as a necessary and significant training tool for emergency response organisations, many current crisis simulations are still focused on the revision of existing response plans only. However, a crisis requires a rapid reaction, yet in contrast to an 'emergency', the risks for critical decision makers in crisis situations are difficult to measure, owing to their ill-structure. In other words, a crisis situation is likely to create great uncertainty, unfamiliarity and complexity, and consequently should be managed by adaptive or second order expertise and techniques, rather than routine or structured responses. In this context, the paper attempts to prove that the current practices of simulation exercises might not be good enough for uncertain, unfamiliar, and complex 'crisis' situations, in particular, by conducting case studies of two different underground fire crises in Korea (Daegu Subway Fire 2003) and the UK (King's Cross Fire 1987). Finally, it is suggested that the three abilities: 'flexibility', 'improvisation' and 'creativity' are critical in responding to a crisis situation.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.533-540
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• 2014

As for the application system or the user authentication scheme that is used in the system, various technologies including simple ID/PW, certificate, fingerprint/iris, phone, security card, and OTP are being used. But simple ID/PW and phone certification lack security features. As for the certificate, fingerprint/iris, and security card/OTP, the weakness in security has been quite strengthened, but there are costs and complexity involved to use these. This paper proposes a new measure of much safer and low-cost user authentication that improves the security level and uses mobile external storage media such as USB that people commonly have.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.1
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• pp.85-101
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• 1995

Automated Guided Vehicles(AGVs) are widely used in computer integrated manufacturing(CIM) systems for material handling purposes. Although automated guided vehicles provide higher levels of flexibility and computer integrability, the installations are limited in number and one of the critical reasons lies in the complexity involved in the operation. The main objective of this research is to alleviate this problem by proposing efficient integrated operational control methods for AGV-based CIM systems. Particularly, this research is concerned with the mixed problem of dispatching automated guided vehicles and scheduling machines operation. The proposed dynamic heuristic algorithm uses various priority schemes and relevant information concerning the load of the system, the status of queues, and the position of AGVs in the scheduling process. The scheduling decision process is hierarchical in the sense that different decision criteria are applied sequentially to identify the most appropriate part to be served. This algorithm consists of two sections, the section of part selection by AGVs for the next service whenever an AGV completes the current assignment, and the section of part selection by machines for next service whenever a machine completes the current operation. The proposed algorithm has been compared with other scheduling schemes using the performance measure of mean flow-time and mean tardiness. Simulation results indicate that the proposed algorithm can reduce the mean flow-time and mean tardiness significantly.

• The Journal of Korean Society for Radiation Therapy
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• v.9 no.1
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• pp.71-81
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• 1997

I. Objective and Importance of the Project We have been using MC-50 cyclotron and NT-50 neutron therapy machine for treating cancer patients since 1986 at Korea Cancer Center Hospital. It is mandatory to measure accurately the dose distribution and the total absorbed dose of fast neutron for putting it to the clinical use. At present the methods of measurement of fast neutron are proposed largely by American Associations of Physicists in Medicine (Task Group 18), European Clinical Neutron Dosimetry Group, and International Commission on Radiation Units and Measurements. The complexity of measurement, however, induce the methodological differences between them. In our study, therefore, we tried to establish a unique technique of measurement by means of measuring the emitted doses and the dose distribution of fast neutron beam from neutron therapy machine, and to invent a standard method of measurement adequate to our situation. II. Scope and Contents of the Project For establishing a unique technique of measurement and inventing a standard method of measurement of fast neutron beam, 1. to grasp the physical characteristics of neutron therapy machine 2. to study the principles for measrement of fast neutron beam 3. to get the dose distribution (dose rate, percent-depth dose, flatness etc) throught the actual measurement 4. to compare our data with those being cited world-widely.

• KIISE Transactions on Computing Practices
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• v.23 no.3
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• pp.156-164
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• 2017

Measuring the similarity of two graphs is a basic tool to solve graph problems in various applications. Most graph algorithms have a high time complexity according to the number of vertices and edges. Because Graphics Processing Units (GPUs) have a high computational power and can be obtained at a low cost, these have been widely used in graph applications to improve execution time. This paper proposes an efficient parallel algorithm to measure graph similarity using the CUDA on a GPU environment. The experimental results show that the proposed approach brings a considerable improvement in performance and efficiency when compared to CPU-based results. Our results also show that the performance is improved significantly as the size of the graph increases.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.241-245
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• 2011

In an engine test, data are collected in a form of a time series. Usually only the time average of a time series is interesting to engineers while its stochastic fluctuation is being ignored. In this paper, we collect pressure and fuel flux data from an air-breathing engine test and analyze their fluctuations using the multiscale sample entropy analysis, which is suggested as a measure of the complexity of a time series. It is shown that different physical quantities indeed have different complexities at each timescales, suggesting a possibility of an instantaneous tool which evaluates the engine test.

• Smart Structures and Systems
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• v.19 no.6
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• pp.679-694
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• 2017

The complexity, enlargement and irregularity of structures and multi-directional dynamic loads acting on the structures can lead to unexpected structural behavior, such as torsion. Continuous torsion of the structure causes unexpected changes in the structure's stress distribution, reduces the performance of the structural members, and shortens the structure's lifespan. Therefore, a method of monitoring the torsional behavior is required to ensure structural safety. Structural torsion typically occurs accompanied by displacement, but no model has yet been developed to measure this type of structural response. This research proposes a model for measuring dynamic torsional response of structure accompanied by displacement and for identifying the torsional modal parameter using vision-based displacement measurement equipment, a motion capture system (MCS). In the present model, dynamic torsional responses including pure rotation and translation displacements are measured and used to calculate the torsional angle and displacements. To apply the proposed model, vibration tests for a shear-type structure were performed. The torsional responses were obtained from measured dynamic displacements. The torsional angle and displacements obtained by the proposed model using MCS were compared with the torsional response measured using laser displacement sensors (LDSs), which have been widely used for displacement measurement. In addition, torsional modal parameters were obtained using the dynamic torsional angle and displacements obtained from the tests.

• Knowledge Management Research
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• v.9 no.3
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• pp.77-105
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• 2008

This study primarily aims at identifying what factors significantly affect the diffusion of knowledge management systems(KMS) and finding out how these identified factors can be effectively managed, especially for Korean companies. The research model is derived based on previous researches on innovation diffusion, information systems implementation, and KMS. The model is used to examine the role of determinants in influencing the extent to which KMS is diffused within organizations. Independent variables of this research are composed of technical characteristics, organizational characteristics and environmental characteristics. 'Breadth of diffusion' and 'depth of diffusion' concept are used to measure the extent of KMS diffusion which is the dependent variable of this model. The 101 companies of total 1,000 samples responded to the survey. To analyze tile results of this empirical study, we performed the multiple regression analysis. As a result, it was shown that the relative advantage, complexity, information system maturity, size, top management support, champion, competitive pressure have influences on both the breadth and the depth diffusions. On the other hand, the organizational culture, valuation and compensation, and uncertainty of environmental factors were not verified to be significant. This empirical study will provide Korean companies with insights into effective ways to diffuse the KMS and succeed in business competition.

• Journal of Applied Reliability
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• v.16 no.3
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• pp.245-253
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• 2016

Purpose: The purpose of this study is to measure the reliability of complex equipment. Reliability of product is one of the most important factor to achieve competitiveness in the market. While there were many researches for assessing the reliability on components and modules, research on quantitative assessment tool for equipment with many component was little because of equipment's complexity. Methods: In this article, we developed index to assess reliability management system by using IEC 60300 and Reliability Management Tool-kit. With MIR and BARS, we developed reliability index clauses relevant to reliability activities and found weight factor for each clause by survey on experts. Results: The results of this study were as follows; reliability index that can assess both management side and technology side of the company was developed. Conclusion: Using this index, we assessed the reliability of a manufacturing equipment and found out the current reliability level of the manufacturing equipment, and derived improvement points.