• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1181-1187
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• 2012

For the fatigue design of aircraft landing gear, the safe-life approach is applied. Structural defects such as cracks or detrimental deformations should not occur under the fatigue load spectrum depicting the entire lifetime usage of the aircraft. In the design phase, the fatigue life of the landing gear is estimated analytically by adopting the stress-based approach because the fatigue of aircraft landing gear is generally high-cycle fatigue. This utilizes S-N curves that are factored to produce design curves that account for the scatter and surface finish of the material. In the test and evaluation phases, a fatigue test should be conducted for full-scale landing gear to substantiate the fatigue design requirement in the end. In this study, the procedure for the fatigue test and evaluation of aircraft landing gear is presented with real application cases.

• Journal of the Korean Dietetic Association
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• v.13 no.1
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• pp.15-29
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• 2007

This study was designed to : (a) investigate the present situations of a college union foodservice and suggest authority on establishing new college foodservice, (b) estimate the service quality attributes as perceived by students, (c) identify the effecting factor to customer satisfaction, and (d) formulate the plans and marketing strategies for the increasing usage rate of the foodservice in the future. The questionnaire that developed by interviewing student were conducted with 305 male and female students, who were registered for daytime classes. A total of 284 were usable and data was analyzed by the SPSS(ver. 11.0) for the descriptive analysis, factor analysis, reliability test, multiple regression analysis, t-test, and $x^2$. The decrease in the usage rate of college foodservice by the respondents were influenced most by the 'taste of meal' and next by the 'distance'. The service quality attributes of foodservice currently under operation were evaluated above the average only for the 'price' while evaluated generally to be in the lower level of the average or under for others. As the overall level of satisfaction with the college union foodservice, most of the respondents showed the 36% for the ‘dissatisfaction’ and dissatisfied at 54.4%. Two service quality dimensions,"food . sanitation . service" and "price and comfortable environment" were derived from factor analysis and the reasons for decreasing usage rate of the college foodservice both the nearly located group from college union foodservice(NG) and the far away located group from college union foodservie(FG) indicated the ‘poor taste’ and the 'far distance', and the 'evaluation of students' dining room showed a low rating for the factor of "food . sanitation . service". "food . sanitation . service" was analyzed to have more influence to the overall customer satisfaction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.3
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• pp.633-652
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• 2024

Software testing is an important phase as it ensures the software quality. The software testing process comprises of three steps: generation, execution, and evaluation of test cases. Literature claims the usage of single and multiple 'Unified Modeling Language' (UML) diagrams to generate test cases. Using multiple UML diagrams increases test case coverage. However, the existing approaches show limitations in test case generation from UML diagrams. Therefore, in this research study, we propose an approach to generate the test cases using UML State Chart Diagram (SCD), Activity Diagram (AD), and Sequence Diagram (SD). The proposed approach transforms UML diagrams into intermediate forms: SCD Graph, AD Graph, and SD Graph respectively. Furthermore, by integrating these three graphs, a System Testing Graph (STG) is formed. Finally, test cases are identified from STG by using a traversal algorithm such as Depth First Search (DFS) that is an optimization method. The results show that the proposed approach is better compared to existing approaches in terms of coverage and performance. Moreover, the generated test cases have the ability to detect faults at the unit level, integration, and system level testing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.831-837
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• 2015

Many persons and electronic devices are exposed to electromagnetic (EM) waves generated from magnetic resonance imaging (MRI) equipment, EM pulses (EMPs), and many other kinds of EM wave devices. Finger strips are used to provide shielding from these EM waves. Because of the high thermal conductivity of finger strips, they are used in the design of specialized doors that are installed in shielded rooms. In this study, we perform an accelerated life test using the load acceleration stress, which affects the main failure mode of finger strips. We predict the life of the finger strip under normal usage conditions based on the results of the accelerated life test. We compare the results with those predicted from the life test under normal usage conditions to evaluate the validity of accelerated life testing.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.122-133
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• 2009

As wireless spectrum resources become more scarce while some portions of frequency bands suffer from low utilization, the design of cognitive radio (CR) has recently been urged, which allows opportunistic usage of licensed bands for secondary users without interference with primary users. Spectrum sensing is fundamental for a secondary user to find a specific available spectrum hole. Cooperative spectrum sensing is more accurate and more widely used since it obtains helpful reports from nodes in different locations. However, if some nodes are compromised and report false sensing data to the fusion center on purpose, the accuracy of decisions made by the fusion center can be heavily impaired. Weighted sequential probability ratio test (WSPRT), based on a credit evaluation system to restrict damage caused by malicious nodes, was proposed to address such a spectrum sensing data falsification (SSDF) attack at the price of introducing four times more sampling numbers. In this paper, we propose two new schemes, named enhanced weighted sequential probability ratio test (EWSPRT) and enhanced weighted sequential zero/one test (EWSZOT), which are robust against SSDF attack. By incorporating a new weight module and a new test module, both schemes have much less sampling numbers than WSPRT. Simulation results show that when holding comparable error rates, the numbers of EWSPRT and EWSZOT are 40% and 75% lower than WSPRT, respectively. We also provide theoretical analysis models to support the performance improvement estimates of the new schemes.

• Journal of the Korean housing association
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• v.8 no.1
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• pp.37-48
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• 1997

The purpose of this study supply data that can make a living room a more comfortable space by using a plan of furniture usage, that is to say more affective to human's mental and physical character. For this purpose made experiment with slide film on 39 representative descriptions. The object of this research was female university students and to analyze the data. factor analysis. One-way ANOVA and scheffe-test were used by running SPSS PC+ program. The major results are as follows. In experiment with slide film for grasping spatial effect and evaluation on the 39 representative descriptions, three dimensions(clearness. openness. variety) extracted as the result of factor analysis. Especially the result of this study - sizes of space put independent valuables and each demotion put dependent valuables - shows differences according to space’ size.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1465-1473
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• 1994

This paper describes the development strategy and contents of a fatigue life evaluation system, FLEVA. The system is composed of 4 parts; material properties, load histories, cycle counting and life prediction. The cycle counting is based on the rain-flow counting method and peak counting method, and the life prediction is performed based on the linear damage rule. Material properties(static, fatigue) are also provided as a database obtained by a computer aided test system. Case study is performed to verify the developed program.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.122-129
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• 2013

The vehicle's waning sounds are used for the purpose of informing the specific situation to the driver. In the past, the warning sounds were developed in terms of a simple notification. With the increasing importance of the emotional quality of vehicle, the research in terms of sound quality has been actively conducted. The desired sounds are dependent upon customer expectation and usage requirements. And it based on cultural or regional difference and personal preference. In this paper, the preference study considering the sale region and personal preference is introduced. Jury test for subjective evaluation are carried out and the difference in preference is analyzed.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.3
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• pp.75-83
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• 2019

Purpose: There are no clear criteria for slip performance in the BF certification process, so the evaluator relies on subjective judgments depending on the field situation. Physical criteria for determining the slip performance of various floor finishes are not clear. C.S.R., the only criterion currently being used to check slip performance, may raise questions about its coverage, feasibility and reliability. Method: For an analysis of domestic standards and status, KS L 1001, KS M 3510, and KS F 2375. External standards are analyzed for ADA Standard, ANSI Standard, and BS EN Standard. Analyze the test methods and evaluation criteria of O-Y-PSM, BPT, and the dynamic slip resistance test used in these criteria. It also presents an improvement plan for the rational presentation of standards. Results: To date, various kinds of test methods and measuring devices of the slip resistance coefficient have been developed, but there are not many ways to trust useful results related to user safety. Reliability and thoroughly verified test methods and criteria should be used to assess the slip performance of the floor. In order to improve the standard for the evaluation of slip performance in Korea, the existing standard should first be raised to the same level as the overseas standard, and the application of the discriminatory standard should be applied considering the characteristics and usage patterns of each space. Implication: Currently, Korean standards propose various test methods, but the proper use of test methods, scope and assessment criteria are not established, so improvement of the comprehensive standard is necessary.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.348-354
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• 2016

Data stored in hospital information systems has a great potential to improve adequacy assessment and quality management. Moreover, an establishment of a data warehouse has been known to improve quality management and to offer help to clinicians. This study constructed a data mart that can be used to analyze antibiotic usage as a part of systematic and effective data analysis of infection control information. Metadata was designed by using the XML DTD method after selecting components and evaluation measures for infection control. OLAP-a multidimensional analysis tool-for antibiotic usage analysis was developed by building a data mart through modeling. Experimental data were obtained from data on antibiotic usage at a university hospital in Cheonan area for one month in July of 1997. The major components of infection control metadata were antibiotic resistance information, antibiotic usage information, infection information, laboratory test information, patient information, and infection related costs. Among them, a data mart was constructed by designing a database to apply antibiotic usage information to a star schema. In addition, OLAP was demonstrated by calculating the statistics of antibiotic usage for one month. This study reports the development of a data mart on antibiotic usage for infection control through the implementation of XML and OLAP techniques. Building a conceptual, structured data mart would allow for a rapid delivery and diverse analysis of infection control information.