• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1305-1310
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• 2010

In a practical design process, the method of extracting the design space information of the complex system for verifying, improving, and optimizing the design process by taking into account the design variables and their shape tolerance is very important. Finite element analysis has been successfully implemented and integrated with design of experiment such as D-Optimal array; thus, a response surface model and optimization tools have been obtained, and design variables can be optimized by using the model and these tools. Then, to guarantee the robustness of the design variables, a robust design should be additionally performed by taking into account the statistical variation of the shape tolerance of the optimized design variables. In this study, a new approach based on the use of the response surface model is proposed; in this approach, the standard normal distribution of the shape tolerance is considered. By adopting this approach, it is possible to simultaneously optimize variables and perform a robust design. This approach can serve as a means of efficiently modeling the trade-off among many conflicting goals in the applications of finite element analysis. A case study on the robust optimal design of disc brakes under thermal loadings was carried out to solve multiple objective functions and determine the constraints of the design variables, such as a thermal deformation and weight.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.901-908
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• 2006

With the development of wireless communication techniques and mobile environment we are able to transmit data between mobile systems without restriction of time and space. Recently, researches on the data communication between mobile systems have focused on a small amount of sending out or receiving data and data synchronization at a fixed server and mobile clients in mobile environment. However, two more servers should be able to move mutual independently, information is shared with other systems, and data is synchronized in the special environment like a battlefield situation. Therefore, we propose a data synchronization method between systems moving mutual independently in mobile environment. The proposed method is an optimization solution to data propagation path between servers that considers limited bandwidth and process of data for disconnection communication. In addition, we propose a data reduction method that considers importance and sharing of information in order to reduce data transmission between huge servers. We verified the accuracy of data after accomplishing our data synchronization method by applying it in the real world environment. Additionally, we showed that our method could accomplish data synchronization normally within an allowance tolerance when we considered data propagating delay time by server extension.

• Journal of Korean Society of Transportation
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• v.23 no.3 s.81
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• pp.35-47
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• 2005

This paper is to review a literature concerning Bus Transit Route Network Design(BTRNDP), to describe a future study direction for a systematic application for the BTRNDP. Since a bus transit uses a fixed route, schedule, stop, therefore an approach methodology is different from that of auto network design problem. An approach methodology for BTRNDP is classified by 8 categories: manual & guideline, market analysis, system analytic model. heuristic model. hybrid model. experienced-based model. simulation-based model. mathematical optimization model. In most previous BTRNDP, objective function is to minimize user and operator costs, and constraints on the total operator cost, fleet size and service frequency are common to several previous approach. Transit trip assignment mostly use multi-path trip assignment. Since the search for optimal solution from a large search space of BTRNDP made up by all possible solutions, the mixed combinatorial problem are usually NP-hard. Therefore, previous researches for the BTRNDP use a sequential design process, which is composed of several design steps as follows: the generation of a candidate route set, the route analysis and evaluation process, the selection process of a optimal route set Future study will focus on a development of detailed OD trip table based on bus stop, systematic transit route network evaluation model. updated transit trip assignment technique and advanced solution search algorithm for BTRNDP.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.13-21
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• 2010

One of the most distinguished features of the DHP association rules mining algorithm is that it counts the support of hash key combinations composed of k items at phase k-1, and uses the counted support for pruning candidate large itemsets to improve performance. At this time, it is desirable for each hash key combination to have a separate count variable, where it is impossible to allocate the variables owing to memory shortage. So, the algorithm uses a direct hashing mechanism in which several hash key combinations conflict and are counted in a same hash bucket. But the direct hashing mechanism is not efficient because the distribution of hash key combinations is unvalanced by the characteristics sourced from the mining process. This paper proposes a mapped perfect hashing function which maps the region of hash key combinations into a continuous integer space for phase 3 and maximizes the efficiency of direct hashing mechanism. The results of a performance test experimented on 42 test data sets shows that the average performance improvement of the proposed hashing mechanism is 7.3% compared to the existing method, and the highest performance improvement is 16.9%. Also, it shows that the proposed method is more efficient in case the length of transactions or large itemsets are long or the number of total items is large.

• Journal of KIISE
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• v.43 no.1
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• pp.126-134
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• 2016

Due to the merits of OLED displays such as fast responsiveness, wide view angle, and power efficiency, their use has increased. However, despite the power efficiency of OLED displays, the portion of their power consumption among the total power consumption is still high since user interaction-based applications such as instant messaging, video play, and games are frequently used. Their power consumption varies significantly depending on the display contents and thus color transformation is one of the low-power techniques used in OLED displays. Prior low-power color transformation techniques have not been rigorously studied in terms of satisfaction of the human visual system, and have not considered optimal visual satisfaction and power consumption at the same time in relation to color transformation. In this paper, we propose a novel low-power color transformation technique which strictly considers human visual system-awareness as well as optimization of both visual satisfaction and power consumption in a balanced way. Experimental results show that the proposed technique achieves better human visual satisfaction in terms of visuality and also shows on average 13.4% and 22.4% improvement over a prior one in terms of power saving.

• Journal of radiological science and technology
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• v.25 no.2
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• pp.57-64
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• 2002

The recent development of embodiment technology of the medical images makes most medical institutions introduce PACS(Picture Archiving and Communication System) in haste. However lots of PACS solutions, currently developed and distributed, haven't been able to serve the convenience of users and to satisfy user's demand because of economic limitations and administrator-oriented considerations in the process of development. So we have developed MIH(Medical Image History), by which we can search and refer to the patient's medical images and information with few restrictions of time and space for diagnosis and treatment. This program will contribute to the improvement in the medical environment and meet the clients' need. We'll make more effort to develop the application which insures the better quality of medical images. MIH manages the patient's image files and medical records like film chart in connection with time. This trial will contribute to the reduction of the economical loss caused by unnecessary references and improve the quality in the medical services. The demand on the development or the program which refers to the medical +ata quickly and keeps them stable will be continued by the medical institute. This will satisfy the client's demand and improve the service to the patients in that tile program will be modified from the standpoint of the users. MIH is trying to keep user-oriented policy and to apply the benefit of the analog system to the digital environment. It is necessary to lead the public to the better understanding that the systematic management and referring of the medical images is as important as the quality of the images.

• Tunnel and Underground Space
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• v.22 no.4
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• pp.227-242
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• 2012

Youngju multipurpose dam is planned to minimizing the damage by flood and obtaining the water for industrial use in Nakdong river region. Faults in rock mass have strong influences on the behaviors of dam structure. Thus, it is very important to analyse for the characteristics of fault rocks in dam design. However, due to the limitation of geotechnical investigation in design stages, engineers have to carry out the additional geological survey including directional boring to find the distribution of faults and the engineering properties of faults for stability of dam. Especially, the selection of location of dam and type of dam considering fault zone must be analyzed through various experimental and numerical analysis. In this study, various geological survey and field tests were carried out to analyse the characteristics of the large fault zone through the complex dam is designed in foundation region. Also, the distribution of structural geology, the shape of faults and the mechanical properties of fault rock were studied for the reasonable design of the location and type of dam for long-term stability of the complex dam.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.148-159
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• 2021

This study focused on searching for optimal locations for general high schools by considering the minimum move distance and the maximum student capacity upon starting a common curriculum based on a high school credit system by taking Seoul as an illustration. The main results were as follows. First, the results from P-median showed that the students' average move distance was below 625m when more than 30% of general high schools offer the common curriculum courses. In addition, the results from MCLP indicated that it was possible to hold all the students. Second, although all the universities located in Seoul open the common curriculum courses, it would not be available to hold all students. On the other hand, when more than 20% of the universities open the courses, MCLP indicated that it was possible to hold the same capacity. In addition, the Office of Education should support moving to the universities offering courses for students affiliated with high schools located in the southeastern area of Seoul and in poor transportation areas. It is expected that by suggesting a problem solving framework regarding space with a spatial optimization method, the study results can be used as a basic data for selecting schools offering common curriculum courses.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.919-929
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• 2022

As a new type of healthy public space, greenway users carry out leisure activities, exercise, sightseeing and necessary transportation in greenway. However, at present, there is little research on greenway users' evaluation and perception of greenway, and there is no comprehensive exploration of Greenway environment from a humanistic perspective. Combined with the research and actual situation of the existing representative greenways in Chinese cities, this paper refers to a large number of documents, applies the semantic difference method and multiple regression analysis method, analyzes the current situation of the Dongfengqu greenway, explores the influencing factors and impact evaluation of the greenway environment from the perspective of greenway users' perception, and puts forward suggestions on the optimization of the greenway environment in Zhengzhou from multiple levels. The main conclusion of this paper comes from the data conclusion obtained by semantic difference method, which is feasible in the resident evaluation of greenway use. The feedback results of post use evaluation can provide a reliable reference for the planning and design of similar greenways in the future.

• Journal of Life Science
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• v.33 no.3
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• pp.268-276
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• 2023

This study was conducted to optimize the formulation conditions of the immediate-release layer of carvedilol in the development of a two-layer tablet formulation for carvedilol and ivabradine. Using a 2⁴+3 full-factorial design of experiments, excipients (microcrystalline cellulose, citric acid, and crospovidone) of the carvedilol immediate-release layer (wet granulation part) and process parameters for the tablet compression process (main compression) were optimized, and seven types of each dependent variable (assay, content uniformity, hardness, friability, disintegration, and dissolution [pH 1.2 and 6.8]) were evaluated using design expert software. The analysis of variance results confirmed that the main compression has a significant effect on hardness, friability, and disintegration time and that microcrystalline cellulose has a major effect on friability and dissolution. In addition, it was confirmed that citric acid has a significant effect on friability. Crospovidone affects friability and dissolution. According to the design space from the design of the experiment results, the optimized range is microcrystalline cellulose (~18.0-32.0 mg), citric acid (~0.5-12 mg), and main compression (~615-837 kgf). Consequently, this study confirmed the availability of manufacturing the carvedilol immediate-release layer in which all risk factors evaluated in the initial risk assessment are removed.