• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.2A
• /
• pp.95-104
• /
• 2010

In wireless communication system, a variety of retransmission algorithms are used in order to improve the quality of service of users. But the system may be inefficient because retransmission algorithms operate independently with other layers. Also, the quality of service can be degraded due to the unnecessary retransmission of packets. To solve these problems, the study on the cross-layer retransmission schemes have been widely performed. However, in order to apply cross-layer retransmission schemes to wireless communication system, whether the performance of cross-layer retransmission schemes meets QoS requirements of each service class has to be verified. Thus, this paper proposes the mathematical model for analyzing the performance of the cross-layer retransmission schemes and derives both the suitable retransmission scheme and the optimal retransmission parameter on each service class. The proposed mathematical model selects the MCS level based on channel state information and The performance analysis is comparatively easy in case that HARQ, ARQ, and AMC schemes are combined. The proposed mathematical model also enables the analysis of the packet transmission delay. To utilize the analytical model, this paper derives the suitable retransmission scheme and the optimal retransmission parameter for delay sensitive services in WiMAX system. Also, the proposed analytical model can be used to analyze the performance of wireless communication system such as LTE and WLAN.

• Journal of Family Resource Management and Policy Review
• /
• v.23 no.3
• /
• pp.89-107
• /
• 2019

This study aimed to examine the impact of academic background on full-time employment and on other important issues concerning job security and care faced by single-parent youths. The study alse aimed to verify the effect of related support on full-time employment. The analysis targeted 262 single parents under 24 years of age who were raising their children, and the main results were as follows: First, the ratio of adulthood was high for those who were employed, and the academic achievement of full-time workers was also significantly high. However, the rate of discontinuities in school was also high among those who were employed, especially those seeking full-time employment, whose desire to stay in school was higher than that of other difficulties of single, teenage parents. Second, the vocational education experience of single, teenage parents was 32 percent overall, and the rate of those seeking full-time employment was also relatively high, reaching 44 percent. However, the results of this study did not verify the direct effect of vocational education experience on full-time employment nor the interaction effect of the academic background. Therefore, a thorough review of the effectiveness of a vocational education program for young, single parents wishing to gain employment is necessary. Third, the overall rate of those who received a public nanny service was 31 percent, while the rate of full-time workers who experienced this service was significantly higher reaching 59 percent. In the research model verification, single parents who received a public nanny service were 3.8 times more likely to get a full-time job than those who did not, and receiving a public nanny service showed a regulatory effect between academic studies and full-time employment. The higher the academic level of the parents, the higher their possibility of full-time employment.

• Smart Structures and Systems
• /
• v.15 no.3
• /
• pp.683-698
• /
• 2015

Railroad bridges form an integral part of railway infrastructure throughout the world. To accommodate increased axel loads, train speeds, and greater volumes of freight traffic, in the presence of changing structural conditions, the load carrying capacity and serviceability of existing bridges must be assessed. One way is through system identification of in-service railroad bridges. To dates, numerous researchers have reported system identification studies with a large portion of their applications being highway bridges. Moreover, most of those models are calibrated at global level, while only a few studies applications have used globally and locally calibrated model. To reach the global and local calibration, both ambient vibration tests and controlled tests need to be performed. Thus, an approach for system identification of a railroad bridge that can be used to assess the bridge in global and local sense is needed. This study presents system identification of a railroad bridge using free vibration data. Wireless smart sensors are employed and provided a portable way to collect data that is then used to determine bridge frequencies and mode shapes. Subsequently, a calibrated finite element model of the bridge provides global and local information of the bridge. The ability of the model to simulate local responses is validated by comparing predicted and measured strain in one of the diagonal members of the truss. This research demonstrates the potential of using measured field data to perform model calibration in a simple and practical manner that will lead to better understanding the state of railroad bridges.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.37 no.3
• /
• pp.75-81
• /
• 2014

To establish a new creative economy, the worldwide efforts have been made to wriggle out the old economic paradigm after the financial crisis of 2008. When it comes to the limitation of the viability. the start up companies have a high risk of failure. Therefore business incubator (BI) should carry out the role to improve their viability. As for the maximization of the effect on the business incubating services as move in companies, it is important for BI to increase the level of business incubating services by the systemic and scientific measurement. This study showed that the quality of the BI center services was measured by Kano analysis and the previous research as follows. First, BI quality attribute by Timko's customer satisfaction came out into the attractive qualities on the 14 items that amount to the 70% of 20 business incubating services items. It is desirable to perform the strategy for the satisfaction. Secondly, basic business incubating services were interpreted as the one-dimensional quality like incubating spaces, parking facilities, security facilities, industry technology development funds, and incubating managers. Finally, training and educational service was recognized as indifferent quality. Futhermore, the improvement and the limitation of this study as well as the interpretation of analysis results are also provided.

• Journal of Korean society of Dental Hygiene
• /
• v.13 no.3
• /
• pp.411-418
• /
• 2013

Objectives : The quality of service is considered as the difference between services that customers perceive and expect by using SERVQUAL model and the basic data for the efficiency of management of dental hospital and clinics, the differentiation strategies of dental medical institutions and the improvements on quality of service are provided. Methods : Subjects were 469 patients who visited six dental hospitals and clinics in Daegu-Gyeongbuk regions. Questionnaire consisted of five items such as type, reliability, responsiveness, certainty and empathy properties. Data were analyzed using SPSS 12.0 program in this study. Results : Women had high satisfaction scores of medical services in certainty and empathy properties. 40s and higher had the highest score in the type property. 30s had high score in the certainty property. For expected service satisfaction, 30s had the highest score in dental practitioners and administrative staffs. For reuse of current medical institution and intent for recommendation, certainty property and factor of dentist and dental practitioners had high scores. Additionally, reliability and responsiveness properties were statistically significant. Conclusions : Medical institutions should make every effort to get the dentists or dental practitioners have the medical knowledge at a high level, a kindness for patients and trust from patients.

• Asia-Pacific Journal of Business
• /
• v.14 no.3
• /
• pp.25-44
• /
• 2023

Receiving medical services abroad is an event that involves a high level of risk and stress for most people. This study proposes and empirically examines perceived control as a factor that has a potential to reduce the stress associated with overseas medical experience and enhance satisfaction with it. Based on the research findings in environmental psychology, one's perceived control was divided into cognitive control, behavior control, and decision control. A research model and a set of hypotheses were constructed to investigate the effect of each control on satisfaction and word-of-mouth communications among consumers who had overseas medical service experiences. The data collection was conducted through an online survey of 220 Chinese consumers who had visited Korea as plastic medicine tourists. Satisfaction with their service experience was significantly affected by both behavioral control and decisional control, but not by cognitive control. Thus, Chinese medical tourists prefer to maintain the belief that they are in charge of major decisions associated with the medical procedure, and that the results of the medical procedure will have personally desirable consequences. In addition, satisfaction experienced by Chinese consumers with overseas medical services had a significant impact on their word-of-mouth activities. Based on the research results, a set of academic and practical implications were derived.

• The Korean Journal of Emergency Medical Services
• /
• v.19 no.3
• /
• pp.51-68
• /
• 2015

Purpose: This study validated the influential relations between the effects of emergency care quality, credibility of 119 emergency medical technicians (119 EMTs), and perceived usefulness and attitude of emergency care, focusing on the moderating effect of protectors' characteristics (education, experience, age, and recognition of patient severity). Methods: This study was based on elaboration likelihood and technology acceptance models. In total, 172 protectors with experience in utilizing prehospital service were surveyed from April 1 to July 31, 2011. Results: The results showed that the emergency care quality and the credibility of 119 EMTs were the main determinants of the perceived usefulness and attitude of emergency care, irrespective of the protector's characteristics (p <.001). In addition, the findings showed that the protector's intention of emergency care had a moderating role. The impact of the quality of emergency care on its perceived usefulness was greater for high-level protectors (p <.001). By contrast, the impact of the credibility of 119 EMTs on the perceived usefulness of emergency care was greater for low-level protectors (p <.001). Conclusion: The protectors' characteristics have different influences on the relations between the effects of emergency care quality, the 119 EMT credibility, and the perceived usefulness and attitude of emergency care.

• Korean Journal of Veterinary Research
• /
• v.47 no.2
• /
• pp.139-145
• /
• 2007

Measurement uncertainty could play an important role in the assessment of test results in laboratories and industries. We investigated measurement uncertainties possibly included in determination of flubendazole, a benzimidazole anthelmintic, in pork by HPLC. The concentration of flubendazole was 62.69 ng/g in a sample of pork. Uncertainty was estimated in the analytical procedure of flubendazole. A model equation was made for determination of flubendazole in pork. The four uncertainty components such as weight of sample, volume of sample, calibration curve, and recovery were selected to estimate measurement uncertainties. Standard uncertainty was calculated for each component and all the standard uncertainties were combined. The combined standard uncertainty was expanded to a sample population as an expanded uncertainty. The expanded uncertainty was calculated using k value on Student's t-table and effective degrees of freedom from Welch-Satterthwaite formula. The expanded uncertainty was calculated as 3.45 with the combined standard uncertainty, 1.584 6 and the k value, 2.18. The final expression can be ($62.69{\pm}3.45$) ng/g (confidence level 95%, k = 2.18). The uncertainty value might be estimated differently depending on the selection of the uncertainty components. It is difficult to estimate all the uncertainty factors. Therefore, it is better to take several big effecting components instead of many small effecting components.

• Culinary science and hospitality research
• /
• v.23 no.6
• /
• pp.110-117
• /
• 2017

This study intended to examine transitive relation among customer incivility perceived by deluxe hotel frontline employees, burnout, and deviant workplace behaviors and clarify the moderating effect of employees' stress. A total of 230 employees working in deluxe hotels in Seoul, the capital of Korea, in 2017 comprised the sample in this study. The hypothesized relationships in the model were tested simultaneously by using structural equation modelling (SEM). As results, customer incivility perceived by deluxe hotel frontline employees had significant (p<.001) positive influence on their burnout(${\beta}=.38$, t-value=4.93). Employees' burnout positively influenced their deviant workplace behaviors (${\beta}=.56$, t-value=7.22). In addition, customer incivility was found to positively affect employees' deviant workplace behaviors(${\beta}=.26$, t-value=3.90), and therefore, the moderating role of stress level was not verified. The findings of this study suggested that deluxe hotels are supposed to enhance their frontline service by providing orientation for customers through promotion materials. Limitations and future research directions of this study were also well established and discussed.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 2008.10b
• /
• pp.365-384
• /
• 2008

Many studies on ASP outsourcing area have focused on the Critical Success Factors(CSFs) of ASP outsourcing projects or on the service quality of ASP Service. But these studies have limitations to explain how to succeed in doing ASP outsourcing project. The objective of this research is to overcome this limitation by using the concept of "IT Risk" in Outsourcing. The effective control of the risks-caused during the IS outsourcing process-gives (ASP service using) users a powerful tool to minimize the risks and thus maximizes the possibility of ASP outsourcing project success. In order to perform this objective, this research set up the research model which is composed of three concepts. The three concepts are 1. Undesirable Outcomes(:UO) as IT outsourcing Risks, 2. The Source of Risks(:SOR) influencing the UO, and 3. the intention to get/execute Real Option Portfolio to control the risk level of SORs and UOs. This research has some important and interesting implications on the ASP outsourcing area. First, this research classifies the risk factors as three concepts and finds the interactions among them. Second, Using Real Option portfolio can control the risks effectively occurred during outsourcing projects. Third, Vendors(ASP service providers) can offer users IN TIME the options which can minimize the occurrence of risks.