• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.489-502
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• 2022

This paper is aimed at developing an optimization-based Finite Element model updating approach for structural damage identification and quantification. A modal flexibility-based error function is introduced, which uses modal assurance criterion to formulate the updating problem as an optimization problem. Because of the inexplicit input/output relationship between the candidate solutions and the error function's output, a robust and efficient optimization algorithm should be employed to evaluate the solution domain and find the global extremum with high speed and accuracy. This paper proposes a new multi-stage Selective Particle Swarm Optimization (SPSO) algorithm to solve the optimization problem. The proposed multi-stage strategy not only fixes the premature convergence of the original Particle Swarm Optimization (PSO) algorithm, but also increases the speed of the search stage and reduces the corresponding computational costs, without changing or adding extra terms to the algorithm's formulation. Solving the introduced objective function with the proposed multi-stage SPSO leads to a smart feedback-wise and self-adjusting damage detection method, which can effectively assess the health of the structural systems. The performance and precision of the proposed method are verified and benchmarked against the original PSO and some of its most popular variants, including SPSO, DPSO, APSO, and MSPSO. For this purpose, two numerical examples of complex civil engineering structures under different damage patterns are studied. Comparative studies are also carried out to evaluate the performance of the proposed method in the presence of measurement errors. Moreover, the robustness and accuracy of the method are validated by assessing the health of a six-story shear-type building structure tested on a shake table. The obtained results introduced the proposed method as an effective and robust damage detection method even if the first few vibration modes are utilized to form the objective function.

• Journal of Home Health Care Nursing
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• v.31 no.1
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• pp.77-88
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• 2024

Purpose: This study aimed to develop and assess the impact of an integrated infection control education program on the awareness, attitudes, and performance of infection control among caregivers in long-term care facilities. Methods: Participants were recruited from two long-term care facilities with 25 caregivers in both the experimental group and the control group. This study used non-equivalent control group quasi-experimental pre-post design. The effectiveness of a developed Integrated Infection Control Education Program was evaluated based on infection control awareness, attitudes, and performance. Data were analyzed using SPSS/WIN 28.0 through descriptive statistics, chi-square tests, Fisher's exact tests, and independent t-tests. Results: There was a statistically significant difference in the degree of awareness (t=-5.00, p<.001), attitude (t=-4.91, p<.001), and performance (t=-6.66, p<.001) of infection control between the two groups. Conclusion: Given these results, the integrated infection control education program significantly improved infection control awareness, attitudes, and performance among caregivers in long-term care facilities. This study is noteworthy because it provided comprehensive education on infection control practices to caregivers in environments that are particularly susceptible to infections, especially following COVID-19. This educational program is actively utilized and validated in practice, it would enhance the infection control performance of caregivers, thereby reducing infection rates within facilities, shortening the length of stay for elderly residents in long term care facilities, and contributing to the reduction of healthcare costs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.10-20
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• 2024

In recent automated manufacturing systems, compressed air-based pneumatic cylinders have been widely used for basic perpetration including picking up and moving a target object. They are relatively categorized as small machines, but many linear or rotary cylinders play an important role in discrete manufacturing systems. Therefore, sudden operation stop or interruption due to a fault occurrence in pneumatic cylinders leads to a decrease in repair costs and production and even threatens the safety of workers. In this regard, this study proposed a fault detection technique by developing a time-variant deep learning model from multivariate sensor data analysis for estimating a current health state as four levels. In addition, it aims to establish a real-time fault detection system that allows workers to immediately identify and manage the cylinder's status in either an actual shop floor or a remote management situation. To validate and verify the performance of the proposed system, we collected multivariate sensor signals from a rotary cylinder and it was successful in detecting the health state of the pneumatic cylinder with four severity levels. Furthermore, the optimal sensor location and signal type were analyzed through statistical inferences.

• Management & Information Systems Review
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• v.22
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• pp.137-165
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• 2007

It seems high time to increase productivity by adopting e-business to overcome challenges posed by both external factors including the appreciation of Korean won, oil hikes and fierce global competition and domestic issues represented by disparities between large corporations and small and medium enterprises (SMEs), Seoul metropolitan and local cities, and export and domestic demand all of which weaken future growth engines in the Korean economy. The demands of the globalization era are for innovative changes in businessprocess and industrial structure aiming for creating new values. To this end, e-business is expected to play a core role in the sophistication of the Korean economy through new values and innovation. In order to examine business performance in e-business-adopting industries, this study analyzed the home shopping industry by closely looking into the financial ratios including the ratio of net profit to sales, the ratio of operation income to sales, the ratio of gross cost to sales cost, the ratio of gross cost to selling, general and administrative (SG&A) expense, and return of investment (ROI). This study, for best outcome, referred to corporate financial statements as a main resource to calculate financial ratios by utilizing Data Analysis, Retrieval and Transfer System (DART) of the Financial Supervisory Service, one of the Korea's financial supervisory authorities. First of all, the result of the trend analysis on the ratio of net profit to sales is as following. CJ Home Shopping has registered a remarkable increase in its ratio of net profit rate to sales since 2002 while its competitors find it hard to catch up with CJ's stunning performances. This is partly due to the efficient management compared to CJ's value of capital. Such significance, if the current trend continues, will make the front-runner assume the largest market share. On the other hand, GS Home Shopping, despite its best organized system and largest value of capital among others, lacks efficiency in management. Second of all, the result of the trend analysis on the ratio of operation income to sales is as following. Both CJ Home Shopping and GS Home Shopping have, until 2004, recorded similar growth trend. However, while CJ Home Shopping's operating income continued to increase in 2005, GS Home Shopping observed its operating income declining which resulted in the increasing income gap with CJ Home Shopping. While CJ Home Shopping with the largest market share in home shopping industryis engaged in aggressive marketing, GS Home Shopping due to its stability-driven management strategies falls behind CJ again in the ratio of operation income to sales in spite of its favorable management environment including its large capital. Companies in the Group B were established in the same year of 2001. NS Home Shopping was the first in the Group B to shift its loss to profit. Woori Home Shopping has continued to post operating loss for three consecutive years and finally was sold to Lotte Group in 2007, but since then, has registered a continuing increase in net income on sales. Third of all, the result of the trend analysis on the ratio of gross cost to sales cost is as following. Since home shopping falls into sales business, its cost of sales is much lower than that of other types of business such as manufacturing industry. Since 2002 in gross costs including cost of sales, SG&A expense, and non-operating expense, cost of sales turned out to have remarkably decreased. Group B has also posted a notable decline in the same sector since 2002. Fourth of all, the result of the trend analysis on the ratio of gross cost to SG&A expense is as following. Due to its unique characteristics, the home shopping industry usually posts ahigh ratio of SG&A expense. However, more than 80% of SG&A expense means the result of lax management and at the same time, a sharp lower net income on sales than other industries. Last but not least, the result of the trend analysis on ROI is as following. As for CJ Home Shopping, the curve of ROI looks similar to that of its investment on fixed assets. As it turned out, the company's ratio of fixed assets to operating income skyrocketed in 2004 and 2005. As far as GS Home Shopping is concerned, its fixed assets are not as much as that of CJ Home Shopping. Consequently, competition in the home shopping industry, at the moment, is among CJ, GS, Hyundai, NS and Woori Home Shoppings, and all of them need to more thoroughly manage their costs. In order for the late-comers of Group B and other home shopping companies to advance further, the current lax management should be reformed particularly on their SG&A expense sector. Provided that the total sales volume in the Internet shopping sector is projected to grow over 20 trillion won by the year 2010, it is concluded that all the participants in the home shopping industry should put strategies on efficient management on costs and expenses as their top priority rather than increase revenues, if they hope to grow even further after 2007.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.1
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• pp.61-67
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• 2013

Wheelchair users have a difficulty in managing their weight because there is lack of measure systems and even though the users have the system, it costs too much. Thus, purpose of this study is for developing the portable weight scale automatic device to help wheelchair users by monitoring their weight on the wheelchairs in real time. Portable weight scale automatic device composed by four strain gauges, and the device was connected with mobile phone so that wheelchair users were able to check their weight in real time. In order to evaluate the device performance, 10 normal subjects and 10 disabled subjects participated in this study. The subjects' truth weight and measured weight by the device are compared. The weigh difference within normal subjects was $0.75{\pm}0.80kg$, and the weigh difference within disabled subjects was $1.02{\pm}0.74kg$. Difference between the truth weigh and the measured weigh were not statistically different. The reason for this error occurred is inaccuracy of the loadcell installation and calibration. If this problems get solved, the measured indicator is expected to help wheelchair users to manage their weight.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.7-16
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• 2013

As workplace incidents has been being declining in Korea, there is criticism of the effectiveness of occupational safety policy implementation. It is unknown that which policy target group needs to be targeted to yield effective injuries prevention. The purpose of this paper is to analyze and reveal the policy intervention group with a high priority in terms of industrial incident prevention and the related investment cost. A Policy Priority Model(PPM) is composed of 6 indicators regarding influences of both the incident reduction and the cost reduction. Z-score analyses are used to confirm the high policy priority area or policy target group. Overall, workplace with worker below 50 persons, construction site with the sales of more than a hundred million won, workplace with relatively small percentage of female employees and relatively higher percentage of older worker should be prioritized to reduce workplace injuries. This paper provides an analytic way that can be used to decide the policy priority workplace in order not only to reduce work-related injuries&illnesses and the related investment cost but to further lessen the related societal costs.

• Clean Technology
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• v.3 no.2
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• pp.57-73
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• 1997

Metal cleaning process is a technology which removes oil, dust and soil etc. on the surface of metal utilizing cleaning agents. These contaminants disturb the following processes such as plating and painting etc. if they are not removed. Thus, metal cleaning is typically an environmentally hazardous activity. Until recently, vapor degreasers as utilizing chlorinated solvents have been relatively cheap, extraordinarily versatile and waste disposal costs have been perceived as insignificant. Today, however, it is readily apparent that Industry's reliance upon chlorinated solvents as metal cleaners have resulted in a myriad of environmental, health and safety concerns. Therefore, this paper studies on a parameter and a sort of the alternative cleaning agents for the optimum cleaners. Also, a great deal of effort has been devoted to developing alternative metal cleaning technologies in advanced countries and some processes are being commercialized among them. We are going to consider alternative aqueous cleaning agents replacing organic chlorinated solvents and to pursue a domain application through a successful improvement case.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.689-699
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• 1996

The purpose of this research is to determine elements affecting the out-of-pocket cost of woman. The sample consisted of 1907 women living Iksan city. The survey was conducted by means of questionnaires. The model used in the analysis of out-of-pocket cost was the Andersen-Newman model, while the analysis techniques used were stepwise multiple regression and path analysis. The number of independent variables used in the analysis was 28 in total, ie 19 predisposing components, 6 enabling components, and 3 need components. In this study, the amount of variance by the model was 17 percent. Number of restricted activity days caused by oral disease, perceived susceptibility of dental disease, having a regular dental care, dental treatment costs, education level and income were found to have significant major effects on out-of-pocket cost. Number of restricted activity days caused by oral disease was the most important variable affecting out-of-pocket cost of woman. Also out-of-pocket cost shows larger effect due to enabling components than frequency of dental utilization.

• Korea Journal of Hospital Management
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• v.11 no.3
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• pp.73-93
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• 2006

This study aims at providing necessary informations for management decision-making to the hospital manager, such as ratios of fixed and variable cost to total operating expense, and variable cost ratio to operating revenues, and determinant factors affecting cost behavior. A study model and related hypotheses were established, data were collected from 41 private university hospitals for the 6years from 1998 to 2003, and regression analyses were performed to test the hypotheses. The results of the analyses and conclusions are as follows; First, labor cost and administration cost within the same number of beds have not only fixed quality of the cost, but variable quality of that. Also, the ratio of the variable costs to operating revenue of the metropolitan was estimated 76.9% and that of other area hospitals was 80.1%. Second, the major factors affecting the increase rate of the operating expense were the increase rates of the number of inpatients, the number of employee, and the number of hospital operating bed. This result implies that maintaining a optimal hospital bed size and efficient operation of the beds are important strategic factors of hospital management.

• Journal of Information Technology Services
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• v.17 no.1
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• pp.105-119
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• 2018

The healthcare business is growing as a global core business because of the phenomenon of global aging, as well as in South Korea, skyrocketing health care costs accordingly, and changing the paradigm from treatment to the prevention-centered medical service. Especially, as the digital healthcare service stands out as a solution, major countries actively promote and support policies at the government level. Thus, this study will present attributes of a market-oriented service that would vitalize the digital healthcare service industry by investigating major attributes of the digital healthcare service. To analyze the relationships of the influences of attributes, this study used Interpretive Structural Modeling. As a result of literature research and ISM, this study can understand the eight basic attributes of the digital healthcare service (network scalability, context awareness, connection among information platforms, cost, trust, security, ease of use, usefulness) and analyze the relationships of the influences among the attributes. In addition, as this study finds some significant differences in Order Winner and Order Qualifier between the experts' group (security) and the users' group (trust, ease of use, usefulness), It provides meaningful implications for revitalization and promotion of digital healthcare service industry.