• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.103-112
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• 2010

In sensor networks, because sensors are deployed in an unprotected environment, they are prone to be targets of compromise attack, If the number of compromised nodes increases considerably, the key management in the network is paralyzed. In particular, compromise of Cluster Heads (CHs) in clustered sensor networks is much more threatening than that of normalsensors. Recently, rekeying schemes which update the exposed keys using the keys unknown to the compromised nodes are emerging. However, they cause some security and efficiency problems such as single group key employment in a cluster, passive eviction of compromised nodes, and excessive communication and computation overhead. In this paper, we present a proactive rekeying scheme using renewals of duster organization for clustered sensor networks. In the proposed scheme, each sensor establishes individual keys with neighbors at network boot-up time, and these keys are employed for later transmissions between sensors and their CH. By the periodic cluster reorganization, the compromised nodes are expelled from network and the individual keys employed in a cluster are changed continuously. Besides, newly elected CHs securely agree a key with sink by informing their members to sink, without exchangingany keying materials. The simulation results shows that the proposed scheme remarkably improves the confidentiality and integrity of data in spite of the increase of compromised nodes. Also, they show that the proposed scheme exploits the precious energy resource more efficiently than SHELL.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.5
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• pp.159-173
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• 2019

The purpose of this study is to examine the effect of service quality of banks on customer satisfaction and recommendation intention through empirical analysis. In particular, the focus was on the differences of the causal effect between PB(Private Banking) customers and regular customers. For this study, two groups were surveyed and 428 valid questionnaires were analyzed. The hypothesis was tested with a structural equation model using AMOS 23.0. As a result, empathy, reliability and tangibles of bank service quality had a positive(+) effect on customer satisfaction. However, responsiveness and assurance were not statistically significant. On the other hand, customer satisfaction has a positive effect on recommendation intention. This study was conducted to compare the two groups, PB customers and regular customers, and found a significant difference. In the PB customers group, tangibles had a positive effect on customer satisfaction, but no other factors were supported. On the other hand, in the regular customers group, empathy and reliability had a positive effect on customer satisfaction while responsiveness, assurance, and tangibles were not supported. Customer satisfaction were analyzed to have a positive influence on recommendation intention in both groups. These findings are academically significant by applying the SERVQUAL factors to banking services and revealing the differences between the PB customers and regular customers. In practice, it is meaningful in that it provided banks with the insights needed for future segmentation and management of customer groups.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.349-355
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• 2021

This study applied aquatic and land-based exercises to breast cancer patients for comparative analysis and elucidation of their effects on the rehabilitation of cancer patients. Participants included 40 breast cancer patients who were divided into two groups: 20 participants in the experimental group using aquatic exercise and 20 participants in the control group using land-based exercise. After the addition of aquatic or land-based exercises five times per week for eight weeks, differences in each group's shoulder and pulmonary functions as well as their quality of life were compared and analyzed. The results showed a statistically significant difference (p<.001) for shoulder dysfunction, with the experimental group showing a greater improvement than the comparison group. Statistically significant differences (p<.05 and p<.001, respectively) were also observed for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), with the experimental group showing greater improvements. Finally, a statistically significant difference (p<.001) was observed for change in the quality of life, with greater improvements in the experimental group than in the control group. The results of further research in this field are expected to indicate the most efficient method for the recovery and management of physical, psychological, and social health impacts of breast cancer on patients. Furthermore, the research aims to provide fundamental resources for breast cancer rehabilitation in South Korea by conducting studies on patients with lung cancer or colorectal cancer and the application of various aquatic exercise methods.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.303-310
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• 2021

This study was conducted to identify the effects of pressure taping between tibia and fibula of High Ankle Sprain athletes on pain, Range of Motion(ROM), and strength and to provide basic data for rehabilitation programs. The subjects of the study were conducted with a total of 10 athletes except for four who gave up who were diagnosed with high ankle sprain, or who were diagnosed with ankle sprain but their physical examinations proved positive. The results showed no significant differences in pain(Visual Analog Scale, VAS). The ROM was significantly increased in inversion(IV) and eversion(EV) in both groups. The Isometric strength was significantly improved in IV(0°, 7°, 14°) and EV(0°) in Taping Group(TG). When taping was applied to athletes with injury to the High Ankle Sprain, ROM and muscle strength improved at the same pain level.

• Korean Public Health Research
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• v.44 no.4
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• pp.35-49
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• 2018

Objective : The purpose of this study was to investigate the risk factors of dehydration from the subjects who underwent anthropometric and blood parameters testing during a comprehensive health screening. Methods : For the study analysis, 5,391 samples with valid data of the levels of Sodium($Na^+$), BUN (Blood Urea Nitrogen) and FBS(Fasting Blood Sugar) were selected to calculate a dehydration indicator of plasma osmolality. The study data was collected from the health screening examinees who visited Sahmyook Medical Center Seoul Adventist Hospital Comprehensive Health Check-up Center from 2014.01.01 to 2015.12.31. The relationship between dehydration and age group, BMI, disease exposures(hypertension, diabetes mellitus, dyslipidemia, kidney disorder) were analyzed by gender. Results : The odds ratio of dehydration showed statistical significance from age ${\geq}50$ in both male and female, respectively. The female obese group was vulnerable to dehydration while the male study group showed no statistical significance in the BMI difference. The disease exposed groups(hypertension, diabetes mellitus, dyslipidemia, kidney disorder) were vulnerable to dehydration. Also, the more types of disease carried by the exposed patients, the higher odds ratio and susceptibility to dehydration. Conclusions : Aging, increasing BMI, and exposed to diseases were found to be the risk factors for vulnerability to dehydration. To prevent dehydration, special caution to be taken for those in the ${\geq}50s$ group, along with controlling BMI and chronic diseases. Further studies are suggested to investigate the risk factors of dehydration that may affect increasing plasma osmolality as a potential stimulus mechanism in disease outbreaks.

• Journal of vocational education research
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• v.30 no.4
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• pp.1-22
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• 2011

Paradoxically, leadership has not only positive effects but also negative effects. The purpose of this study is to examine supervisors' dysfunctional leadership behaviors, antecedents and results in order to draw HRD implications for protecting organizations and employees from dysfunctional leaders and provide implications for leadership development. A qualitative research method based on semi-organized interviews with 28 employees from S-group was used. The results of this study show that the dysfunctional leadership behaviors were associated with ten behavioral categories: belittling and insulting the subordinates, authoritative and arbitrary behaviors, self-aggrandizement, biased preference for certain personnel, arrogance, micro-managing, inability to change and adapt, discordance between words and actions, over-dependance on supervisor, lack of ethics and values. Dysfunctional leadership behaviors were casually attributed to 'personal traits & experience', 'task characteristics', and 'internal & external environments of the organization'. Finally, the results of supervisor's dysfunctional leadership behaviors on employees and the organizational effects were 'increased turnover rate', 'declining work efficiency', 'collapsing morale', 'retraining innovative thinking', 'passive working culture', 'discouraging organizational vitality', 'discouraging organizational synergy', 'losing loyalty' and 'declining trust on supervisor'.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.232-241
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• 2019

This study examines one of the conventional and controversial issues in modern finance. Specifically, this study identifies financial determinants of corporate R&D intensity for firms belonging to Korean Chaebols. Empirical estimation procedures are applied to derive more robust results of each hypothesis test. Static panel data, Tobit regression and stepwise regression models are employed to obtain significant financial factors of R&D expenditures, while logit, probit and complementary log-log regression models are used to detect financial differences between Chaebol firms and their counterparts not classified as Chaebols. Study results found the level of R&D intensity in the prior fiscal year, market-value based leverage ratio and firm size empirically showed their significance to account for corporate R&D intensity in the first hypothesis test, whereas the majority of explanatory variables had important power on a relative basis. Assuming that the current circumstances in the domestic capital market may necessitate gradual changes of Korean Chaebols in terms of their socio-economic function, the results of this study are expected to contribute to identifying financial antecedents that can be beneficial to attain optimal level of corporate R&D expenditures for Chaebol firms on a virtuous cycle.

• Journal of Environmental Impact Assessment
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• v.28 no.2
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• pp.129-140
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• 2019

Majangcheon is a small agricultural stream which is located in Chuncheon-si, Gangwon-do. To understand ecological characteristics of Majangcheon as biological habitats, we surveyed its physical environment and fishes from June 2016 to September 2016. The altitudinal difference between lowest and highest point of the stream was 3 meters and the first-order stream under a map drawn on a scale of 1:25,000. The flow rate of stream was slow in overall with $0.09-0.48m{\cdot}s^{-1}$. More than 50% of clay were found in all points except for the point St. 3 in the riverbed structure surveyed. A total of 2,532 individuals of 22 species in nine families were collected from Majangcheon. Of them, stillwater-living species (Acheilognathinae and Carassius auratus) and floating species (Zacco platypus and Oryzias sinensis) were mainly collected. In Majangcheon, thus, both of stillwater-living and floating fishes were specifically coexisted. The correspondence analysis, based on fishes collected from Majangcheon and past research, showed that Majangcheon is closer to the flat streams in Gyeonggi-do rather than the mountainous streams in Gangwon-do but it appeared as an independent group from those of two regions. As a result, Majangcheon is a stream with specificity of fish community.

• Science of Emotion and Sensibility
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• v.22 no.1
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• pp.45-54
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• 2019

Empathy has been observed to be pivotal in enhancing both social relations and the efficiency of task performance. Empathetic interaction has been shown to begin with individuals mirroring each other's facial expressions, vocal tone, actions, and so on. The internal responses of the cardiovascular activity of people engaged in empathetic interaction are also known to be synchronized. This study attempted to objectively and quantitatively define the rules of empathy with regard to the synchronization of cardiac rhythm between persons. Seventy-four subjects participated in the investigation and were paired to imitate the facial expressions of their partner. An electrocardiogram (ECG) measurement was taken as the participants conducted the task. Quantitative indicators were extracted from the heart rhythm pattern (HRP) and the heart rhythm coherence (HRC) to determine the difference of synchronization of heart rhythms between two individuals as they pertained to empathy. Statistical significance was confirmed by an independent sample t-test. The HRP and HRC correlation(r) between persons increased significantly with empathy in comparison to an interaction that was not empathetic. A difference of the standard deviation of NN intervals (SDNN) and the dominant peak frequency decreased. Therefore, significant parameters to evaluate empathy have been proposed through a step-wise discrimination analysis. Empathic interactions may thus be managed and monitored for high quality social interaction and communication.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.187-193
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• 2019

Key-value storage engines are an essential component of growing demand in many computing environments, including social networks, online e-commerce, and cloud services. Recent key-value storage engines offer many features such as transaction, versioning, and replication. In a key-value storage engine, transaction processing provides atomicity through Write-Ahead-Logging (WAL), and a synchronous commit method for transaction processing flushes log data before the transaction completes. According to our observation, flushing log data to persistent storage is a performance bottleneck for key-value storage engines due to the significant overhead of fsync() calls despite the various optimizations of existing systems. In this article, we propose a group synchronization method to improve the performance of the key-value storage engine. We also design and implement a transaction scheduling method to perform other transactions while the system processes fsync() calls. The proposed method is an efficient way to reduce the number of frequent fsync() calls in the synchronous commit while supporting the same level of transaction provided by the existing system. We implement our scheme on the WiredTiger storage engine and our experimental results show that the proposed system improves the performance of key-value workloads over existing systems.