• Journal of Communications and Networks
• /
• v.14 no.6
• /
• pp.682-691
• /
• 2012

Key agreement protocol is a fundamental protocol in cryptography whereby two or more participants can agree on a common conference key in order to communicate securely among themselves. In this situation, the participants can securely send and receive messages with each other. An adversary not having access to the conference key will not be able to decrypt the messages. In this paper, we propose a novel identity-based authenticated multi user key agreement protocol employing a symmetric balanced incomplete block design. Our protocol is built on elliptic curve cryptography and takes advantage of a kind of bilinear map called Weil pairing. The protocol presented can provide an identification (ID)-based authentication service and resist different key attacks. Furthermore, our protocol is efficient and needs only two rounds for generating a common conference key. It is worth noting that the communication cost for generating a conference key in our protocol is only O($\sqrt{n}$) and the computation cost is only O($nm^2$), where $n$ implies the number of participants and m denotes the extension degree of the finite field $F_{p^m}$. In addition, in order to resist the different key attack from malicious participants, our protocol can be further extended to provide the fault tolerant property.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.14 no.1
• /
• pp.25-34
• /
• 2004

Common Criteria(CC, ISO/IEC 15408) is an international standard for evaluation of Information Suity Systems(ISS). There need a suitable evidence of estimation of evaluation cost in an evaluation facility under the CC-based evaluation and assurance scheme. In this paper, we propose an evaluation effort model, which is based not only on assurance-level but also on product-type of ISS, by means of real experience of real evaluators, use-ratio concept and the Function Point of security function. The model is based not on a real evaluation environment of evaluation facility, but on CC, public PPs and product specific STs. Our result might be used as a basic model for estimation of evaluation cost and time of ISS in an CC-based evaluation and assurance scheme.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.2
• /
• pp.609-614
• /
• 2016

Background: Although breast cancer is the most common cancer in women, economic evaluation of breast cancer screening is not fully addressed in developing countries. The main objective of the present study was to analyze the cost-effectiveness of breast cancer screening using mammography in 35-69 year old women in an Iranian setting. Materials and Methods: This was an economic evaluation study assessing the cost-effectiveness of a population-based screening program in 35-69 year old women residing in rural areas of South east Iran. The study was conducted from the perspective of policy-makers of insurance. The study population consisted of 35- to 69-year old women in rural areas of Kerman with a population of about 19,651 in 2013. The decision tree modeling and economic evaluation software were used for cost-effectiveness and sensitivity analyses of the interventions. Results: The total cost of the screening program was 7,067.69 US$ and the total effectiveness for screening and no-screening interventions was 0.06171 and 0.00864 disability adjusted life years averted, respectively. The average cost-effectiveness ratio DALY averted US$ for screening intervention was 7,7082.5 US$ per DALY averted and 589,027 US $ for no-screening intervention. The incremental cost-effectiveness ratio DALY averted was 6,264 US$ per DALY averted for screening intervention compared with no-screening intervention. Conclusions: Although the screening intervention is more cost-effective than the alternative (noscreening) strategy, it seems that including breast cancer screening program in health insurance package may not be recommended as long as the target group has a low participation rate.

• Journal of Preventive Medicine and Public Health
• /
• v.41 no.5
• /
• pp.295-299
• /
• 2008

Objectives : The Korean government in January 2006 instigated an exemption policy for hospitalized children under the age of six years old. This study examines how this policy affected the utilization of medical care in Korea. Methods : A total of 1,513,797 claim records from the Health Insurance Review Agency were analyzed by complete enumeration methods. The changes of medical utilization were compared from 2005 to 2006. In addition, the changes of medical utilization between 2004 and 2005 were compared as a pseudo-control group. Results : The admission rate increased 1.14-fold from 15.20% in 2004 to 17.32% in 2005, and this further increased 1.08-fold to 18.65% in 2006. The increase of patients with a common cold (1.2-fold) was higher than that of both the general patients (1.08-fold) and the patients, with the top 10 fatal diseases (0.91-fold). The average length of stay per case for clinics showed the highest increase rates (1.06-fold). The rates of patients with the common cold showed a higher increase (1.05-fold) than that of the general patients. The average medical expense per case was increased by 1.10-fold from 2005 to 2006, which was higher than that from 2004 to 2005 (1.04-fold). The increase rate for patients with the common cold was higher at 1.18-fold than that of the general patients. Conclusions : The cost exemption policy has especially led to an increase in the utilization of clinics and the utilization by patients with a common cold.

• Journal of the Korean Society of Food Culture
• /
• v.34 no.3
• /
• pp.284-295
• /
• 2019

This study examined the actual condition of middle school students' dining out based on the data of the 2016 youth food behavior inquiry data of the Korea Rural Economic Institute. The eating out behavior of 278 middle school students' according to gender, average eating-out cost per person, average monthly eating out cost per person, weekly frequency of breakfast, and dietary information source were calculated into a chi-square value by cross analysis. The main results of this study are as follows. First, in middle school students' eating-out status, most students answered 'eating out', and the highest frequency of eating out was 1~3 times a week. The reason for eating out was 'to enjoy delicious food', and 'costly price' was the most common reason for not eating out. Food taste was the most common standard for selecting eating out, and a restaurant was the most common place to eat out. The main restaurant was the 'snack bar (kimbap specialized store)'. Second, there was no significant difference in all items of eating-out status according to the gender. A significant difference in eating out frequency was observed according to average eating-out cost per once (p< .001), standard for selecting eating out (p< .001), main eating out places (p< .001), and main restaurants (p< .01). There was a significant difference in the frequency of eating out (p< .001) in the eating-out status according to average eating out cost per month. Third, the eating-out status according to the breakfast frequency of middle school students had a significant difference in the reason for eating out (p< .001). The eating-out status according to the dietary information source of middle school students had a significant difference in eating out or not (p< .05) and the frequency of eating out (p< .05). These results highlight the importance of school diet education so that middle school students can achieve healthy eating habits and plan to increase their interest and utilization of school dietary education.

• Journal of Digital Contents Society
• /
• v.5 no.2
• /
• pp.95-100
• /
• 2004

For improve level of information security, the necessity of evaluation and certification of Information Security System(ISS) in increasing. Evalustion and Certification Institute have evaluated ISS for risk prevention of information dysfunction in an advanced countries. But, the problem of the time and cost occurred when it is caused by with application of unlike evaluation criteria each other. The result of effort to solution, Common Criteria(CC) and Common Evaluation Methodology(CEM) is using for evaluation of ISS and mutual recognition. Evaluation participant is needed flexible and active interpretation of CC and CEM for an efficient evaluation preparation and performance.

• Industrial Engineering and Management Systems
• /
• v.9 no.3
• /
• pp.196-203
• /
• 2010

Make-to-forecast production is a way to realize high customization and fast responsiveness. This study firstly investigates the effect of introducing a common component in a make-to-forecast production environment. The common component can eliminate a modification step, which is a major cost component in make-to-forecast production. It is illustrated, however, that introducing a versatile component that merely covers several variants is unattractive, and thus adding values to the common component is inevitable in this environment. Secondly, an order-matching rule under the condition that two partially overlapped delivery lead time intervals exist is proposed. The rule considers the effect of matching orders to units that can cover both intervals. An alternative re-matching rule is also developed and examined. Numerical experiments clarify that the proposed rule generally realizes higher contribution ratio and lower percentages of orphans and rejected orders. The proposed re-matching rule increases the average contribution ratio at the expense of increased orphans and order rejections.

• Journal of Power Electronics
• /
• v.19 no.5
• /
• pp.1326-1335
• /
• 2019

Common mode (CM) chokes are a crucial part in EMI filters for mitigating the electromagnetic interference (EMI) of switched-mode power supplies (SMPS) and for meeting electromagnetic compatibility standards. However, the parasitic capacitances of a CM choke deteriorate its high frequency filtering performance, which results in increases in the design cycle and cost of EMI filters. Therefore, this paper introduces a negative capacitance generated by a negative impedance converter (NIC) to cancel the influence of equivalent parallel capacitance (EPC). In this paper, based on a CM choke equivalent circuit, the EPCs of CM choke windings are accurately calculated by measuring their impedance. The negative capacitance is designed quantitatively and the EPC cancellation mechanisms are analyzed. The impedance of the CM choke in parallel with negative capacitances is tested and compared with the original CM choke using an impedance analyzer. Moreover, a CL type CM filter is added to a fabricated NIC prototype, and the insertion loss of the prototype is measured to verify the cancellation effect. The prototype is applied to a power converter to test the CM conducted noise. Both small signal and EMI measurement results show that the proposed technique can effectively cancel the EPCs and improve the CM filter's high frequency filtering performance.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.6
• /
• pp.1937-1944
• /
• 2014

In recent years, common ducts have been installed and operated in the sidewalls of tunnels to prepare for emergencies in tunnel construction and maintenance. The installation of common ducts is done mainly by humans. Problems with cost increases are inherent in tunnel construction by humans due to the safety risks and the economic inefficiency of humans performing construction activities. Among the problems that arise are poor illumination due to the use of temporarily installed electricity, the risk of accidents due to the confined workspaces, and workers avoiding work tasks because of the poor environment in tunnel. Ideas for solving these problems were developed using a value engineering (VE) process, and mechanized construction was identified as a promising solution. To verify the effectiveness of mechanized construction of a common duct in tunnels, experimental construction work was carried out, and mechanized construction was proven to directly improve the constructability and economic efficiency of common duct construction. In addition, reducing human involvement in common duct construction in tunnels is expected to improve safety, and because of the continuous concrete placement technique used, the finish and appearance of the ductwork are improved.

• International Journal of Highway Engineering
• /
• v.19 no.2
• /
• pp.103-112
• /
• 2017

PURPOSES : In this study, field performance evaluation of crack treatment of pavement and the feasibility of surface treatment of pavement are presented. The performance and cost of preventive maintenance methods have been previously verified, and the methods are being used in many developed countries and cities. However, the performance and cost of the system have not been verified in domestic, field applications. Therefore, in order to improve performance, the field performance is evaluated, and a reasonable cost is proposed. METHODS : Visual Inspection was conducted to evaluate the field application and performance of the preventive maintenance method. In addition, the PCI index was calculated from the results of visual inspection of the application area of the surface treatment method, and the performance life of each method was predicted. For the economic evaluation, life cycle cost analysis was performed using the life cycle cost analysis program. RESULTS :In order to evaluate and quantify the field performance of crack repair material, the residue condition of the pavement surface after crack treatment, rather than the performance of the material, is evaluated. In addition, the crack resistance and performance life of surface treatment methods are evaluated. The cost of currently available treatment methods are compared to the common pavement cut and overlay method, and it is determined that the preventive method is not economical based on life cycle cost analysis. CONCLUSIONS :Because of the characteristics of cracking, it is necessary to conduct the evaluation of currently applied methods and the analysis of the cause of damage, by visual inspection. Moreover, in order to evaluate the performance and economic suitability of the currently applied surface treatment methods, it is necessary to acquire information on application sections by monitoring their long-term conditions and performance.