• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.9
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• pp.739-748
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• 2021

This paper discusses the prediction and validation of design loads of satellite components using modal mass acceleration curve (Modal MAC). To calculate the acceleration upper bound of the satellite components subjected to the launch environment by the Modal MAC, the parameters of SpaceX Falcon 9 launch vehicle were used, and the acceleration upper bound curve in the modal domain was derived. After that, the maximum acceleration loads applied to the satellite components were predicted by combining Modal MAC with the spacecraft interface loads of the satellite/launch vehicle and modal information of the satellite. In addition, the accuracy of the Modal MAC was validated through comparison with the results of the coupled loads analysis using a simple satellite and launch vehicle model.

• The Journal of the Acoustical Society of Korea
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• v.41 no.5
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• pp.525-533
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• 2022

We propose an effective method for suppressing both side and grating lobes by applying 2-dimensional Fourier Transform to the received channel data during the receive focusing process of an ultrasound imaging system. When the signal from the image point is focused, the channel signals have the same DC value across the channels. However, even after echoes from outside an imaging point are focused, they are manifested as having different spatial frequencies depending on their incident angles. Therefore, after the receive focusing delay time is applied, 2-D Fourier Transform is performed on the time-channel data to separate the DC component and other frequency components in the spectral domain, and the weighting value is defined using the ratio of the two values. The side lobe and grating lobe were suppressed by multiplying the ultrasound image by a weighting value. Ultrasound images with a frequency of 5 MHz were simulated in a 64-channel linear array. The grating lobe appearing in the ultrasound image was completely removed by applying the proposed method. In addition, the side lobe was reduced and the lateral resolution was greatly increased. Results of computer simulation on a human organ mimicking image show that the proposed method can aid in better lesion diagnosis by increasing the image contrast.

• International Journal of Computer Science & Network Security
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• v.23 no.7
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• pp.1-8
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• 2023

An Orthogonal Frequency Division Multiplexing (OFDM) based wireless communication system has drawn wide attention for its high transmission rate and high spectrum efficiency in not only radio but also Underwater Acoustic (UWA) applications. Because of the narrow sub-carrier spacing of OFDM, orthogonality between sub-carriers is easily affected by Doppler effect caused by the movement of transmitter or receiver. Previously, Doppler compensation signal processing algorithm for Desired propagation path was proposed. However, other Doppler shifts caused by delayed Undesired signal arriving from different directions cannot be perfectly compensated. Then Receiver Bit Error Rate (BER) is degraded by Inter-Carrier-Interference (ICI) caused in the case of Multi-path Doppler channel. To mitigate the ICI effect, a modified Delay and Doppler Profiler (mDDP), which estimates not only attenuation, relative delay and Doppler shift but also sampling clock shift of each multi-path component, is proposed. Based on the outputs of mDDP, an ICI canceling multi-tap equalizer is also proposed. Computer simulated performances of one-tap equalizer with the conventional Time domain linear interpolated Channel Transfer Function (CTF) estimator, multi-tap equalizer based on mDDP are compared. According to the simulation results, BER improvement has been observed. Especially, in the condition of 16QAM modulation, transmitting vessel speed of 6m/s, two-path multipath channel with direct path and ocean surface reflection path; more than one order of magnitude BER reduction has been observed at CNR=30dB.

• Journal of Preventive Medicine and Public Health
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• v.56 no.6
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• pp.523-532
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• 2023

Objectives: During the second coronavirus disease 2019 (COVID-19) surge, cases increased sharply due to low awareness and compliance with measures to limit disease spread. Health literacy (HL) is an important component of public health initiatives, and schools are potential sources of health education to increase HL via the presentation of COVID-19 educational modules. Methods: This cross-sectional study involved an online questionnaire administered to students from 5 high schools in Surabaya and Sidoarjo, Indonesia, 6-7 weeks after the start of government-issued directives restricting public gatherings. We collected data on each respondent's age, gender, parental education, and socioeconomic variables. HL was determined by the Health Literacy Measure for Adolescents. We additionally measured their attitudes and behaviors related to preventing the spread of COVID-19. The students were asked if they watched the COVID-19 module at school, their feelings about vaccination, and preferred online sources of COVID-19-related information. Results: Most of the 432 respondents had viewed COVID-19 modules at school. Module exposure was associated with significantly higher total and domain-specific HL and more positive attitudes toward government-issued COVID-19 restrictions on travel and public gatherings (p<0.05). However, behaviors to prevent COVID-19 spread and vaccine acceptance were not associated with module exposure. Most students chose social media as their source of COVID-19-related information. Conclusions: Schools can provide information to increase adolescents' HL and the public's support for health initiatives to prevent or limit the spread of COVID-19.

• Journal of Intelligence and Information Systems
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• v.15 no.4
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• pp.1-22
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• 2009

The World Wide Web is transitioning from being a mere collection of documents that contain useful information toward providing a collection of services that perform useful tasks. The emerging Web service technology has been envisioned as the next technological wave and is expected to play an important role in this recent transformation of the Web. By providing interoperable interface standards for application-to-application communication, Web services can be combined with component based software development to promote application interaction and integration both within and across enterprises. To make Web services for service-oriented computing operational, it is important that Web service repositories not only be well-structured but also provide efficient tools for developers to find reusable Web service components that meet their needs. As the potential of Web services for service-oriented computing is being widely recognized, the demand for effective Web service discovery mechanisms is concomitantly growing. A number of techniques for Web service discovery have been proposed, but the discovery challenge has not been satisfactorily addressed. Unfortunately, most existing solutions are either too rudimentary to be useful or too domain dependent to be generalizable. In this paper, we propose a Web service organizing framework that combines clustering techniques with string matching and leverages the semantics of the XML-based service specification in WSDL documents. We believe that this is one of the first attempts at applying data mining techniques in the Web service discovery domain. Our proposed approach has several appealing features : (1) It minimizes the requirement of prior knowledge from both service consumers and publishers; (2) It avoids exploiting domain dependent ontologies; and (3) It is able to visualize the semantic relationships among Web services. We have developed a prototype system based on the proposed framework using an unsupervised artificial neural network and empirically evaluated the proposed approach and tool using real Web service descriptions drawn from operational Web service registries. We report on some preliminary results demonstrating the efficacy of the proposed approach.

• Management & Information Systems Review
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• v.39 no.1
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• pp.93-114
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• 2020

Platform is considered as an alternative strategy to the traditional linear pipeline based business. Moreover, in the 4th industrial revolution period, efficiency driven pipeline business model needs to be changed to platform business. We have such success stories about platform as Apple, Google, Amazon, Uber, and so on. However, for those smaller corporations, it is not easy to find out the transformation strategy. The essence of platform business is to leverage network effect in management. Thus platform based management can be rephrased as network management across the business functions. Research on platform business is popular and related to diverse facets. But few scholars cover what the research trend of the domain is. The main purpose of this paper is to identify the research trend on platform business in Korea. To do that we first propose the analytical model for platform architecture whose components are consumers, suppliers, artifacts, and IT platform system. We conjecture that mapping of the research work on platform to the components of the model will make us understand the hidden domain of platform research. We propose three hypotheses regarding the characteristics of research and one proposition for the transitional path from pipeline to platform business model. The mapping is based on the research articles filtered from the Korea Citation Index, using keyword search. Research papers are searched through the keywords provided by authors using the word of "platform". The filtered articles are summarized in terms of the attributes such as major component of platform considered, platform type, main purpose of the research, and research method. Using the filtered data, we test the hypotheses in exploratory ways. The contribution of our research is as follows: First, based on the findings, scholars can find the areas of research on the domain: areas where research has been matured and territory where future research is actively sought. Second, the proposition provided can give business practitioners the guideline for changing their strategy from pipeline to platform oriented. This research needs to be considered as exploratory not inferential since subjective judgments are involved in data collection, classification, and interpretation of research articles.

• Journal of KIISE:Software and Applications
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• v.37 no.7
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• pp.518-535
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• 2010

Cloud Computing is emerged as an effective reuse paradigm, where service providers operate hardware and software and as a service, and service consumers invoke the service through Internet. Software-as-a-Service (SaaS) is a type of cloud services, where the whole software is designed as a service so that several consumers can reuse the SaaS. While tradition software applications are developed for a specific organization, SaaS is developed for multiple users in the various organizations. Hence, reusability is very essential characteristic of SaaS. Reusability is defined as a metric of how effective and efficient software functionalities can be used by various users. Reusability in SaaS is evaluated by considering three sub-characteristics; applicability, adaptability, and scalability. Since such a SaaS has considerable differences and characteristics from traditional software applications, conventional methods including object-oriented modeling, component-based development method, and service-oriented architecture (SOA) service development method would be limited in developing services which can fulfill these three sub-characteristics related to reusability as well as SaaS-intrinsic characteristics. Hence, there is a great demand for effective processes for developing SaaS cloud services. In this paper, we present a practical process for developing SaaS, which focuses on ensuring reusability. And by performing a case study with our proposed SaaS development process, we evaluate applicability of our proposed process and explain how the process is used in a real domain. Then, we compare our proposed process with others for verifying our study. Through the proposed process, cloud services with high quality can be more effectively developed.

• Quality Improvement in Health Care
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• v.11 no.1
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• pp.32-45
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• 2004

Objective : The aim of this study were to measure quality of life(QOL) in liver transplant recipients, to compare QOL between living donor liver transplant recipients and cadaveric liver transplant recipients and to investigate whether SF-36 may be used as a disease-specific instrument in liver transplant recipients. Methods : We conducted a single-center cross-sectional study of 133 LT recipients ages 13 to 65 years, all of whom had had Liver Transplantation(LT) at least 1 months previously. QOL was assessed using a self-completion questionnaire consisting of the Bang Whal Ran(1991) instruments and the 36-Item Short-Form Health Survey(SF-36) health status profile measure. We investigated whether the SF-36 instrument may be used as a disease-specific instrument in LT recipients. Individual scale scores range from 0 to 100, with higher score reflecting better health. Data on demographics, clinical status at pre transplantation 1 day, post transplantation clinical status, and graft function were collected to identify predictors of post transplantation QOL. Results : Standard measures for test-retest reliability, internal consistency, and discriminant and concurrent validity were examined. The reliability of the SF-36, as measured by test-retest correlation(Pearson coefficients: 0.729, p=0.002) and by internal consistency(Cronbach's alpha: 0.9431) exceeded conventional acceptability criteria. The correlation between domain scores of SF-36 and the Bang Whal Ran(l991) was clear and logical in that the clinical characteristics of SF-36 strongly correlated with the clinical component summary score of the Bang Whal Ran(l991)(r = 0.8155, P<.01). SF-36 scale scores were compared between Cadaveric Liver Transplant recipients and Living Donor Liver Transplant recipients. Donor types of post LT did not influence HRQOL(p>0.05). 87% of the liver transplant recipients were satisfied to get LT. Satisfaction of post LT showed significantly greater HRQOL(p<0.001). Conclusion : SF-36 is found reliable and valid. This study indicates thet Donor Type did not influence HRQOL after LT. The information gained from this study will help us to better define expectations and the clinical course after liver transplantation to patients and their families.

• The Journal of Fisheries Business Administration
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• v.46 no.2
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• pp.75-92
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• 2015

Generally, the outcomes of the historical study in some domain would be a most fundamental and basic reference for understanding the essential and core component of them. Specially in case of social science, the importance of historical research much more emphasized that would be divided into independent academic field. In Korean history including fisheries business and industry, the most remarkable historic event would be the period of Japanese colonial rule that one of the most obstacle should overcome. Though the fisheries business and industry of Korea have considerable own history, the research and study of that not so much have been performed or investigated including the period of Japanese colonial rule. Most of the existing research of fisheries history have merely focused on partial topics like 'Fishermen's Association', 'Fisheries Industry Despoliation'. And the historical study of fisheries business and industry's overall status and trend in local area except Pusan also not enough. The aims of this study are exploring the fisheries trends and status during the period of Japanese colonial rule in Tongyeong and finding out the overall major fisheries business issues that would be a better understanding the Korean fisheries industry. Achieving that Objectives, over 800 articles of media, the Japanese government-general of Korea, and other historical data were gathered, refined and analyzed. This paper focused on of major fisheries topics and issues that including overall fisheries status, trends, fisheries catches, local fisheries cooperatives and fisheries exhibition during the period of Japanese colonial rule in Tongyeong. The result of this study shows that the status of fisheries in Korea had been deteriorated for exploitation of Japanese imperialism and Japanese fisheries capitalist during that period. Though the level of Tongyeong in fisheries was very high in terms of catches ratio and population of fisherman, the distribution networks of fishermen's association was not good enough. And the Tongyeong fisheries exhibition in 1922 has positive aspects for considering both composition of organization and educational activity. Even though the results and findings would be a helpful guidelines for understanding the fisheries business trends and status under the rule of Japanese imperialism, more research and study of that should be accomplished.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.3-12
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• 2000

The multi-region model, to describe preferential flow, is an equation representing solute transport in soils by dividing soil into numerous pore groups and using the hydraulic properties of the soil. As the model partial differential equation (PDE) is solved numerically with finite difference methods. a modified equivalent partial differential equation(MEPDE) of the partial differential equation of the multi-region model is derived to analyze the accuracy and consistency of the solution of the model PDE and the Von Neumann method is used to analyze the stability of the finite difference scheme. The evaluation obtained from the MEPDE indicated that the finite difference scheme was found to be consistent with the model PDE and had the second order accuracy The stability analysis is performed to analyze the model PDE with the amplification ratio and the phase lag using the Von Neumann method. The amplification ratio of the finite difference scheme gave non-dissipative results with various Peclet numbers and yielded the most high values as the Peclet number was one. The phase lag showed that the frequency component of the finite difference scheme lagged the true solution. From the result of the stability analysis for the model PDE, it is analyzed that the model domain should be discretized in the range of Pe < 1.0 and Cr < 2.0 to obtain the more accurate solution.