• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.822-839
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• 2011

Group key agreement protocols derive a shared secret key for a group of users to ensure data confidentiality or/and integrity among the users in the subsequent communications. In this paper, we inspect two group key agreement schemes which have been proposed by Shi et al. and Zheng et al. in 2005 and 2007 respectively. Although both schemes were claimed to be secure in a heuristic way, we reveal several flaws using the Bellare-Rogaway security model extended to multi-party setting by Bresson et al. These flaws are found to be originated from inappropriate selection of key derivation function, inadvertent exclusion of partners' identities from the protocol specification and insufficient consideration in preserving known temporary information security and key freshness properties. Furthermore, we suggest and discuss proper countermeasures to address such flaws.

• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.53-61
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• 2018

In this paper, the author proposes an efficient group key agreement scheme in a mobile environment where group members frequently join and leave. This protocol consists of basic protocols and general ones and is expected to be suitable for communications between a mobile device with limited computing capability and a key distributing center (or base station) with sufficient computing capability. Compared with other schemes, the performance of the proposed protocol is a bit more efficient in the aspects of the overall cost for both communication and computation where the computational efficiency of the scheme is achieved by using exclusive or operations and a one-way hash function. Also, in the aspect of security, it guarantees both forward and backward secrecy based on the computational Diffie-Hellman (CDH) assumption so that secure group communication can be made possible. Furthermore, the author proves its security against a passive adversary in the random oracle model.

• Journal of International Academy of Physical Therapy Research
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• v.7 no.2
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• pp.999-1005
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• 2016

The purpose of this study was to investigate the effects of low-intensity cardiac rehabilitation exercise on the cardiac function and the degree of fibrosis in an older white rat model. This study used male Sprague-Dawley white rats that were 50 weeks old. After the acute myocardial infarction induction, Twenty of the rats were randomly allocated into an experimental group and a control group, and each of the groups consisted of 8 rats. In the experimental group, the exercise was conducted for six weeks, 30 minutes a day, five days a week, using a Rotarod treadmill for animals. The degree of myocardial fibrosis was significantly repressed in the experimental group($13.69{\pm}1.90%$) and in the control group($15.67{\pm}1.54%$)(p<0.05). However, fractional shortening and ejection fraction did not show a significant difference. The results of this study suggest that cardiac rehabilitation with low intensity treadmill exercise repress the myocardial fibrosis.

• Journal of the Society of Disaster Information
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• v.5 no.1
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• pp.122-139
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• 2009

USN Middleware plays roles of broker between sensors and applications. It collects sensor data, decides the situation and sends the result to the applications. It is not good to decide the situation from one sensor data, because it may error data or reflect small part of all. In this paper, we propose the disaster management model based on the concept 'group' and 'semantic information' from the sensing data. Group is the primary unit to decide the situation. It consists of several sensors which were installed in the same place and had the same pre-defined condition to act. For example, all fire sensors in the room simultaneously trigger the ring when the same pre-defined temperature is recorded. Then, the all fire sensors are included to the same one sensor group. All operations of the intelligent USN middleware are based on the 'group' unit. Disaster information is the result of the interpretation of the sensing data. based on the 'group', the disaster meaning is processed.

• Journal of Distribution Science
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• v.14 no.8
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• pp.45-50
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• 2016

Purpose - This study aimed to develop a new practical and universally applicable service quality model by improving the service quality measurement model proposed by many previous studies. Research design, data, and methodology - An in-depth analysis on what influences such service quality model had on the improvement effect of service quality, and Service Evaluation Model("SEM"), which was revised from the existing service quality measurement model, was developed. The model is divided into the two integrative categories: First, activity, that is the group of service-related activities. Next is item, the group of service-related objects. The level of service is evaluated for each category via survey questionnaire on service level evaluation. Based on the model, SEM has visibility by structuring the whole service industry. Results - For the application of the new service quality model, this study attempted to examine the appropriateness of the newly proposed service quality model by applying it to retail service field. Conclusions - As a result, the proposed service model would be a useful and applicable service quality measurement model required by many organizations. Service company can set up self check service levels. Through these results, they can look for the ways to provide better services to customers. Service users can ensure the objectivity of business plan based upon SEM.

• Journal of Korean Biological Nursing Science
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• v.11 no.2
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• pp.99-104
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• 2009

Purpose: An animal model of pressure ulcers was experimentally-induced with the use of greater trochanter of rats. Methods: Twelve male Sprague-Dawley rats were used in this study and they were randomly divided into 4 groups: Group I (n=3, 120 mmHg, 2 hr), Group II (n=3, 120 mmHg, 3 hr), Group III (n=3, 140 mmHg, 3 hr) and Group IV (n=3, 140 mmHg, 4 hr). The rats were anesthetized with 100 mg/kg of ketamine. The pressure ulcers were induced by using a personally-designed pressing apparatus. After 5 days, the wounds were photographed and excised. Results: After 5 days of induced pressure ulcers, it was observed that Group I and Group II responded with Grade I and Grade II, respectively, while Group III and Group IV responded with Grade III. Conclusion: According to the result of this study, it can be concluded that the pressure ulcers were induced the characteristic grades of pressure ulcer classification by adjusting the degree and the duration of compression.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.81-86
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• 2014

In this paper, a jointly optimal group replacement and spare provisioning policy is presented. Most maintenance policies assume that the spare inventory is always available, but in practice the maintenance schedule is affected by the availability of spare inventory. We present a maintenance-inventory model which jointly optimizes the group replacement interval and spare ordering quantity. Group replacement policy is used when a group of units are put in operation simultaneously. The operating fleet is replaced altogether at a predetermined number of units are failed. A sufficient level of spare inventory is carried to perform a number of group replacement. A cost rate expression which considers the group maintenance cost and inventory holding cost is derived and a heuristic method for searching the optimum value of decision variables is suggested. Numerical examples demonstrate the analytical results and the performance of the presented model.

• Journal of Acupuncture Research
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• v.27 no.5
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• pp.1-12
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• 2010

Objectives : This study was designed to evaluate the antidiabetes effects of Cinnamomum cassia and Aconitum carmichaeli in type II diabetes mellitus model mice. Methods : The experimental animals were divided into 3 groups and treated for 50 days as follows:control group, pharmacopuncture group and extract administration group. The effects of Cinnamomum cassia and Aconitum carmichaeli were observed by measuring body weight, blood glucose, insulin, insulin immunoreactivity of the pancreas and subpopulation of splenocytes. Results : Cinnamomum cassia sample groups were reduced a little body weight than control group. Glucose level of extract administration group lowered than control and pharmacopuncture group. Insulin immunoreactivity of Aconitum carmichaeli extract group appeared more effective than control and pharmacopuncture group. Conclusions : This study shows that Cinnamomum cassia and Aconitum carmichaeli have a distinct antidiabetes effect in type II diabetes mellitus model.

• Research in Community and Public Health Nursing
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• v.18 no.3
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• pp.363-372
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• 2007

Purpose: This study is to examine the effects of the drinking-reduction program that utilizes transtheoretical model and leisure ability model on the problem drinking behavior, alcohol outcome expectancy, and abstinence self-efficacy of. problem drinkers at workplaces. Method: The subjects consisted of 54 male problem drinkers who scored over 12 points in the AUDIT-K with 23 persons in the experimental group and 31 persons in the control group. The research results were analyzed using the SAS program with Chi-square test, t-test, repeated ANOVA, and post-hoc comparison. Results: 1) The experimental group showed a significantly lower score in problem drinking behavior than the control group. 2) The experimental group showed a significantly lower score in alcohol outcome expectancy than the control group. 3) The experimental group showed a significantly higher score in abstinence self-efficacy than the control group. Conclusion: These results demonstrate that the drinking-reduction program effectively reduces the drinking behavior of problem drinkers at workplaces, reduces alcohol outcome expectancy, and enhances abstinence self-efficacy. Accordingly, it is considered that a drinking-reduction program can be a useful nursing intervention method for problem drinkers at workplaces to reduce drinking and improve the quality of life.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.1
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• pp.117-123
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• 2002

To investigate the antiinflammatory and analgesic effects of Sophorae radix extracts administered to the arthritic rat model, immunohistochemical stains for CGRP in the L4, L5 and L6 spinal cord and ganglia were done, and paw swelling thickness were measured. Complete Freund,s Adjuvant(CFA) were injected to subcutaneous tissue of left foot paw of rats to induce arthritis. Sophorae radix extracts was administered immediately after CFA injection for 10 days. The spinal cord and ganglia were frozen sectioned(30㎛). These sections were stained by CGRP immunohistochemical staining method, and observed with light microscope. The results were as follows : 1. The change of paw swelling thickness of experimental group decreased from 4 day to 10day after CFA injection compared to control group. 2. The change of differential leukocytes counts of experimental group increased the ratio of lymphocytes. and decreased the ratio of neutrophils compared to control group. 3. The change of CGRP immunoreactive nerve fiber of dorsal horn of experimental group was dense stained compared to control group. 4. The number of CGRP immunoreactive neurons of L4 and L5 spinal cord of experimental group was less than in those control group. These results suggested that Sophorae radix extracts reduces the number of CGRP immunoreactive neurons and nerve fibers of spinal cord and ganglia, and decrease paw swelling thickness in arthritic rat model, which may be closely related to analgesic and antiinflammatory effects of Sophorae radix.