• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.93-115
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• 2014

In collaborative product development with multiple suppliers, buyers must manage the suppliers' activities. This empirical research investigates the performance impacts of three strategies that buyers use to manage suppliers who design interdependent components. These strategies are: Instructionism (giving clear instructions to suppliers), Teaming (forming an interactive development team with suppliers), and Delegation (transferring component development responsibilities to suppliers). Data were collected through a cross-industry web-based survey of buying firms in manufacturing industries whose products require multiple, interdependent components. A path analysis utilizing 318 survey responses indicates that Instructionism has a positive effect on design quality, and Teaming has a positive effect on design quality and component innovation. The use of Delegation is not related to any of the performance indicators. The practical implication of this research for product development managers is that both Instructionism and Teaming can be effective strategies. For the purpose of assuring design quality, a buyer should give clear instructions in detailed specifications or work closely with suppliers in development teams. If competitive priority is product innovativeness, however, the buyer should work closely with its suppliers during component development processes using a Teaming strategy.

• Journal of Communications and Networks
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• v.12 no.4
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• pp.334-345
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• 2010

In this paper, we study optimal tradeoffs of achievable throughput versus consumed power in wireless ad-hoc networks formed by a collection of multiple antenna nodes. Relying on adaptive modulation and/or dynamic channel coding rate allocation techniques for multiple antenna systems, we examine the maximization of throughput under power constraints as well as the minimization of transmission power under throughput constraints. In our examination, we also consider the impacts of enforcing quality of service requirements expressed in the form of channel coding block loss constraints. In order to properly model temporally correlated loss observed in fading wireless channels, we propose the use of finite-state Markov chains. Details of fading statistics of signal-to-interference-noise ratio, an important indicator of transmission quality, are presented. Further, we objectively inspect complexity versus accuracy tradeoff of solving our proposed optimization problems at a global as oppose to a local topology level. Our numerical simulations profile and compare the performance of a variety of scenarios for a number of sample network topologies.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.636-647
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• 2012

Construction projects have become so large, complicated and incredibly high-tech that process management is currently considered one of the most important issues. Unlike typical manufacturing industries, most major construction activities are performed in the open air and thus are exposed to various environmental factors. Many studies have been conducted with the goal of establishing efficient techniques and tools for overcoming these limitations. Productivity analysis and prediction, one of the related research subjects, must be considered when evaluating approaches to reducing construction duration and costs. The aim of this research is to present a quantified impact analysis of construction delay factors on construction productivity of a steel staircase system, which has been widely applied to high rise building construction. It is also expected to improve the process by managing the factors, ultimately achieving an improvement in construction productivity. To achieve the research objectives, this paper analyzed different delay factors affecting construction duration by means of multiple regression analysis focusing on steel staircase systems, which have critical effects on the preceding and subsequent processes in structure construction. Statistical analysis on the multiple linear regression model indicated that the environment, labor and material delay factors were statistically significant, with 0.293, 0.491, and 0.203 as the respective quantified impacts on productivity.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.408-418
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• 2022

Marine accidents involving the entanglement of marine litter have continued to increase, with over 300 to 400 cases per year according to the statistical agency. Entanglement of marine litter may also lead to large-scale marine accidents which cause capsizing and sinking, thereby further causing detrimental casualties and material damages, and thus exceptional attention and care are required. In this study, Incheon, Busan, and Geoje and Tongyeong were found to be the high-frequency locations for accidents, which were selected by considering the ArcGIS analysis about the marine accidents of entanglement of marine litter and the occurrence frequency by the standard. The characteristics of the multiple accident areas involving entanglement of marine litter were the coastal cities where fishing facilities or marine leisure related conditions were activated, with the port which handles much of the traffic of outbound and inbound vessels located nearby. Marine plastic pollution impacts not only the marine ecosystem and food chain, but also the hull and engine of ships, and may further pose threats to the safety of vessels and crews. It is necessary to find a common link between the relevant areas and to strive to remove the root causes of marine accidents by reducing marine litter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.261-279
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• 2023

In this article, the uplink achievable rate is investigated for massive multiple-input multiple-output (MIMO) under correlated Ricean fading channel, where each base station (BS) and user are both deployed multiple antennas. Considering the availability of prior knowledge at BS, two different channel estimation approaches are adopted with and without prior knowledge. Based on these channel estimations, a two-layer decoding scheme is adopted with maximum ratio precoding as the first layer decoder and optimal second layer precoding in the second layer. Based on two aforementioned channel estimations and two-layer decoding scheme, the exact closed form expressions for uplink achievable rates are computed with and without prior knowledge, respectively. These derived expressions enable us to analyze the impacts of line-of-sight (LoS) component, two-layer decoding, data transmit power, pilot contamination, and spatially correlated Ricean fading. Then, numerical results illustrate that the system with spatially correlated Ricean fading channel is superior in terms of uplink achievable rate. Besides, it reveals that compared with the single-layer decoding, the two-layer decoding scheme can significantly improve the uplink achievable rate performance.

• Asia pacific journal of information systems
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• v.23 no.1
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• pp.65-86
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• 2013

Understanding success factors in electronic banking is important to helping banks succeed. In this study, we extend DeLone and McLean's IS success model to the electronic banking by adding trust as a success variable. We tested the extended model by comparing internet banking and mobile banking in Indonesia. Using a structural equation modelling approach. We found that system quality had positive impacts on perceived usefulness and end-user satisfaction for both internet banking and mobile banking. The development of e-banking (internet banking and mobile banking) in Indonesia is in its initial stage. Finally, although we tested for the common method bias to relieve concern, further research may use multiple methods when collecting the data. This study investigated the role of each dimension of IS success in the electronic banking environment. While the original IS success model emphasizes individual and organizational impacts, we have argued that trust is an important indicator of IS impact on an individual socially in the banking industry. The contribution of our study is two-fold. Conceptually, the study is the first to extend the IS success model to the e-banking context. We provide an extension of the updated IS success model by adding trust as an outcome variable in the research model.

• The Journal of Korean Academic Society of Nursing Education
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• v.20 no.2
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• pp.192-202
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• 2014

Purpose: The purpose of this study was to identify the impacts of social support and acculturative stress on depression among Korean registered nurses in the United States. Method: In total, 137 nurses were recruited through direct interviews and online surveys. The data were collected through a structured questionnaire from June 1, to September 16, 2012, and analyzed using descriptive statistics, t-test, ANOVA, Scheff$\acute{e}$'s test, Pearson correlation coefficient, and stepwise multiple regression with SPSS WIN 14.0. Results: Social support significantly differed by the length of one's nursing career in US, monthly income and perceived health status. Acculturative stress significantly differed by the length of one's nursing career in US and types of employment setting. Depression significantly differed by the total length of one's nursing career, type of employment setting, and perceived health status. Moreover, Depression was negatively correlated with social support; positively correlated with acculturative stress; social support was negatively correlated with acculturative stress. Factors influencing depression were acculturative stress, perceived health status, and social support, which explained about 23% of the total variance. Conclusion: These results suggest that an adaptation program that decreases acculturative stress and improves social support should be developed and implemented for Korean nurses to help them successfully integrate into the healthcare system of new country.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.4
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• pp.159-173
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• 2004

Instant Messenger is a communication tool which allows instant real-time connection between parties through Internet Compared to the most popular Internet communication tool. email. the messenger allows people to check network presence of other parties and to connect in real time among multiple parties. Mostly due to the convenience it provides. use of instant messengers has increased tremendously not only for personal purpose but also for business purpose. However. firms are agonizing about the real impact of instant messenger usage among employees. whether the impact is positive or negative in terms of the productivity, Applying the theory of reasoned action (TRA) and technology acceptance model (TAM). this study sets UP perceived ease of use. perceived usefulness and cultural orientation of individuals as antecedents of adoption and use of the messenger application, Also. the impacts of messenger usage are measured as task productivity and intimacy among colleagues. This study presents several findings about the instant messenger, First. perceived ease of use. and usefulness play important roles in raising the adoption level of instant messenger. Also. culture propensity also maintains strong influence towards the actual usage of the messenger. Among cultural variables. innovativeness, supportiveness and outcome orientation reveal strong positive impacts on adoption and use of the messenger. On the dependent side. use of instant messenger seems to have a strong direct impact on task productivity as well as indirect impact through intimacy. Implications are discussed.

• The Journal of Korean Academic Society of Nursing Education
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• v.26 no.1
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• pp.67-77
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• 2020

Purpose: This study was conducted to determine the impacts of perceived stress and self-compassion on the quality of life of nursing students. Methods: Data were collected from 180 nursing students between 11 October and 26 October 2018 from a college in A city. A total of 157 questionnaires were analyzed using descriptive statistics, t-tests, a one-way ANOVA, Pearson correlation, and stepwise multiple regression. Results: The findings show that perceived stress had a significant negative correlation with quality of life (r=-.73, p<.001). However, self-compassion showed a significant positive correlation with quality of life (r=.66, p<.001). The factors influencing quality of life included perceived stress, self-compassion, state of health, and satisfaction with school life, with perceived stress being the most influential factor (β=-.42), followed by self-compassion (β=.30), which together had an explanatory power of 64.0%. Moreover, there was a mediating effect of self-compassion in the relationship between perceived stress and quality of life. Conclusion: The results of this study indicate that nursing college students should search for ways to reduce their perceived stress as well as increase self-compassion with meditation programs in order to improve their quality of life.

• Journal of Korean Clinical Nursing Research
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• v.21 no.2
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• pp.234-242
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• 2015

Purpose: The purpose of this study was to investigate the levels of knowledge and medication adherence to hormonal therapy (HT) and to identify the factors influencing medication adherence for patients with breast cancer. Methods: Data were collected from 136 patients undergoing adjuvant HT for breast cancer in 3 general hospitals from July 1 to August 14 in 2014 using self-report questionnaires. Data were analyzed using descriptive statistics, independent t-test, ANOVA, $Scheff{\grave{e}}$ test, and multiple regression. Results: The average of knowledge about HT was $5.15{\pm}2.22$ (Max 9), and that of medication adherence was $5.76{\pm}1.65$ (Max 8). Younger age, shorter duration of HT, more active participation in decision making for treatment, positive perception for impacts of HT, and stronger belief in cure were influencing factors on higher adherence level. Age, duration of HT, and perception on the impacts of hormonal therapy, and belief in cure explained 25.2% of the adherence. Conclusion: To improve the treatment adherence to hormonal therapy, patient education and involvement in decision making, and the tailored intervention for the patients with older age, and long treatment period of HT are needed. Additionally, the strategies for diminishing unintentional forgetting is necessary to be developed.