• 자원환경지질
• /
• 제44권6호
• /
• pp.533-539
• /
• 2011

미국에서는 재난으로 인한 기반시설물의 피해를 줄이기 위해 국가기반시설 리질리언스 확보가 국가기반시설보호계획에 활용되고 있다. 여기서 "리질리언스"는 재난으로 인한 시스템의 영향을 효율적으로 줄일 수 있는 기반시설 시스템의 능력으로, 리질리언스 비용으로 정량화가 시도되었다. 리질리언스 비용은 시스템 영향과 복구노력을 합한 것으로, 리질리언스 평가 사례는 리질리언스 평가시 복구노력을 고려할 필요가 있음을 보여주고 있다. 본 논문은 리질리언스 비용을 설명하고, 연구 사례를 통해 리질리언스 비용의 평가 방법을 보여주고자 한다.

• 조명전기설비학회논문지
• /
• 제29권8호
• /
• pp.83-89
• /
• 2015

This study suggests the methodology to decide the number and adequate capacity of substation transformer in a large-scale offshore wind farm (OWF). The recent trend in transformer capacity of offshore substation is analyzed in many European offshore wind farm sites prior to entering the studies. In order to carry out the economic evaluation for the transformer capacity we present the cost models which consist of investment, operation, and expected energy not supplied (EENS) cost as well as the probabilistic wind power model of wind energy that combines the wind speed with wind turbine output characteristics for a exact calculation of energy loss cost. Economic assessment includes sensitivity analysis of parameters which could impact the 400-MW OWF: average wind speed, availability, discount rate, energy cost, and life-cycle.

• Structural Engineering and Mechanics
• /
• 제88권3호
• /
• pp.273-285
• /
• 2023

This study examines how the interaction between soil and a wind turbine's supporting system affects the optimal design. The supporting system resting on an elastic soil foundation consists of a steel conical tower and a concrete circular raft foundation, and it is subjected to wind loads. The material cost of the supporting system is aimed to be minimized employing various metaheuristic optimization algorithms including teaching-learning based optimization (TLBO). To include the influence of the soil in the optimization process, modified Vlasov and Gazetas elastic soil models are integrated into the optimization algorithms using the application programing interface (API) feature of the structural analysis program providing two-way data flow. As far as the optimal designs are considered, the best minimum cost design is achieved for the TLBO algorithm, and the modified Vlasov model makes the design economical compared with the simple Gazetas and infinitely rigid soil models. Especially, the optimum design dimensions of the raft foundation extremely reduce when the Vlasov realistic soil reactions are included in the optimum analysis. Additionally, as the designated design wind speed is decreased, the beneficial impact of soil interaction on the optimum material cost diminishes.

• IEIE Transactions on Smart Processing and Computing
• /
• 제1권2호
• /
• pp.95-105
• /
• 2012

The widespread implementation of RFID in ubiquitous computing is constrained considerably by privacy and security unreliability of the wireless communication channel. This failure to satisfy the basic, security needs of the technology has a direct impact of the limited computational capability of the tags, which are essential for the implementation of RFID. Because the universal application of RFID means the use of low cost tags, their security is limited to lightweight cryptographic primitives. Therefore, EPCGen2, which is a class of low cost tags, has the enabling properties to support their communication protocols. This means that satisfying the security needs of EPCGen2 could ensure low cost security because EPCGen2 is a class of low cost, passive tags. In that way, a solution to the hindrance of low cost tags lies in the security of EPCGen2. To this effect, many lightweight authentication protocols have been proposed to improve the privacy and security of communication protocols suitable for low cost tags. Although many EPCgen2 compliant protocols have been proposed to ensure the security of low cost tags, the optimum security has not been guaranteed because many protocols are prone to well-known attacks or fall short of acceptable computational load. This paper proposes a remedy protocol to the flyweight RFID authentication protocol proposed by Burmester and Munilla against a desynchronization attack. Based on shared pseudorandom number generator, this protocol provides mutual authentication, anonymity, session unlinkability and forward security in addition to security against a desynchronization attack. The desirable features of this protocol are efficiency and security.

• Journal of Preventive Medicine and Public Health
• /
• 제37권2호
• /
• pp.141-149
• /
• 2004

Objectives : To evaluate the cost and proportion of complementary and alternative medicines (CAM) in the total healthcare costs among the elderly in the last 6 months of life. Methods : The care-giving families of 301 persons older than 65 years, who died between July 1st and December 31st of 2001, and were also registered in Self-Employed Health Insurance Programs in Seoul, were interviewed. Results : The cost of CAM was 1.09 million Won, which as a proportion of the total healthcare cost was 38.1%. The elderly aged between 65 and 69 year-old, male, living with their spouse, Buddhist and having cancers had higher CAM costs in an ANOVA and simple regression analysis. After controlling of various factors, age was the only significant factor associated with the cost of CAM. The elderly above 80 years old, female, bereaved and Buddhist had higher proportional CAM costs, and the elderly having cancers or cardiovascular diseases had lower proportional CAM costs in an ANOVA and simple regression analysis. After adjusting for various factors, the elderly above 85 years old, female and Buddhist had higher proportional CAM costs, and the elderly having cancers had lower proportional CAM costs. Conclusion : The very old and Buddhist, and/or the ill with no clear diagnosis, may depend more on CAM. Further research will be needed on the meaning and impact of CAM and their costs to public health and the total healthcare system.

• 대한통합의학회지
• /
• 제4권3호
• /
• pp.39-47
• /
• 2016

PURPOSE : This study attempts to find the effects of water perturbation exercise performed on stroke patients in their physiological cost index and gait ability tests. METHOD : The subjects were 30 stroke patients, water perturbation exercise group was performed 3 day per week, for 40 minutes a day, for a period of eight weeks. The physiological cost index and gait of all subjects were assessed by using the polar, 6 Minute Walk Test (6MWT), and 10 meter Walk Test(10mWT) at pre training and post training. Paired t-test was used to analyze change before and after intervention in group. Pearson's correlation was used to analyze correlation of all variables. RESULT : Water perturbation exercise group showed increased physiological cost index. Water perturbation exercise increased gait ability, showing a significant difference. Showing the correlation between the relatively high amount between physiological cost index and 6 minutes walking test. CONCLUSION : From the result of the study, we found that water perturbation exercise was effective in improving physiological cost index and gait ability. The patient is considered to be used by itself to involve the treatment and the risk of falling from the lowered state into the treatment method for the intensive treatment of stroke patients to be useful in improving the cardiovascular system and ability to walk. Through underwater training for stroke patients in the future on the basis of this study it is considered to require additional clinical studies on the impact on daily living and quality of life of stroke patients.

• 한국임상약학회지
• /
• 제26권1호
• /
• pp.59-69
• /
• 2016

Background: The subcutaneous formulation of biologic disease-modifying antirheumatic drugs (DMARDs) was preferred due to favored self-administration and would be an economical treatment option for patients with rheumatoid arthritis. This study was to compare the economic impact of biologic DMARDs administered by subcutaneous injection in patients with rheumatoid arthritis who had inadequate response to conventional DMARDs. Methods: The cost-minimization analysis was conducted to estimate the lifetime health care costs of treatment sequences with subcutaneous biologic DMARDs as first-line therapy from a health care system perspective. The Markov model was developed to represent the transitions through treatment sequences based on American College of Rheumatology response rate and discontinuation rate. The health care costs comprised the cost of medications, administration, dispensing, outpatient visits, test/diagnostic examination, palliative therapy and treatment of serious infection. All costs were expressed in 2016 Korean Won (KRW) and discounted at 5%. Results: The mean lifetime health care cost per patient was lowest in the etanercept sequence, which was estimated at KRW 63,441,679. The incremental costs of the treatment sequence started with adalimumab, golimumab, abatacept, and tocilizumab were KRW 7,985,730, KRW 4,064,669, KRW 2,869,947, and KRW 4,282,833, respectively, relative to etanercept sequence. These differences in costs mainly were attributable to medication costs. One-way and probabilistic sensitivity analyses confirmed that etanercept represented the option with the lowest cost compared with comparators. Conclusion: This study found that etanercept is likely a cost-saving treatment option among subcutaneous biologic DMARDs in patients with rheumatoid arthritis.

• 한국정보전자통신기술학회논문지
• /
• 제11권4호
• /
• pp.460-466
• /
• 2018

정보기술의 발달로 컴퓨터 소프트웨어 시스템의 규모는 끊임없이 확장되고 있다. 소프트웨어 개발에 대한 신뢰성 및 비용은 소프트웨어 품질에 큰 영향을 미치고 있다. 본 연구에서는 소프트웨어 고장 간격시간 자료를 바탕으로 NHPP 모형에서 Type-2 Gumbel과 Erlang 분포의 형상모수를 따르는 수명분포에 근거한 소프트웨어 개발 비용모형에 관한 특성을 비교하고, 분석하였다. 그 결과, Go-Okumoto 모형 및 제시한 모형인 Erlang 모형과 Type-2 Gumble 모형에 대한 비용곡선의 추세는 모두 초기단계에서 감소하다가, 고장시간이 지나는 후반부에 가서는 점차 증가하는 결과를 보였다. 또한, Erlang 모형과 Type-2 Gumble 모형을 비교한 결과, Erlang 모형이 소프트웨어 출시시기가 빠르고, 출시시점의 비용도 경제적임을 알 수 있었다. 본 연구를 통하여, 소프트웨어 운용자들은 소프트웨어 출시시기 이후에 결함이 감소되도록 운영단계보다 테스팅 단계에서 결함들을 제거해야 하며, 소프트웨어 개발비용에 관한 특성을 파악하는데 필요한 사전정보을 연구할 수 있을 것으로 기대된다.

• 보건행정학회지
• /
• 제24권3호
• /
• pp.219-227
• /
• 2014

Background: Current trends in Korea population aging with advances in public health and clinical medicine foretell rises in the prevalence of not only chronic diseases but also patients with multimorbidity. One important aspect in analyzing multimorbidity is to define the list of chronic diseases included when calculating multimorbidity index. The objective of this study is to describing the effect of multimorbidity on healthcare cost in Korea using US Office of the Assistant Secretary of Health (OASH) list. Methods: We analyzed the Korea Health Panel Data representing non-institutionalized Korean adult populations aged 20 and more. We calculated multimorbidity index based on OASH list and estimated the prevalence and healthcare cost for each OASH chronic disease. Results: In 2011, 15.2 million (39.6%) Koreans aged 20 and more were living with chronic condition. The health care cost due to chronic diseases, accounted for 80.2% of the overall healthcare costs and the prevalence of chronic conditions, the prevalence of multimorbidity and healthcare cost increased with ages. In the analysis using OASH list, 40% of the adult population over the age of 20 and 66.7% of the population over the age of 65 was affected with multimorbidity. In most of diseases in OASH list, prevalence of mulitmorbidity was high and healthcare cost increased with multimorbidity. Conclusion: OASH chronic disease list that accounts for 72.4% of prevalence and 86.7% of healthcare cost of persons with chronic conditions in Korea. OASH chronic disease list would be a useful and representative indicator for studying multimorbidity.

• 한국철도학회논문집
• /
• 제15권2호
• /
• pp.97-103
• /
• 2012

허니컴 샌드위치 복합재는 가볍고 강하며, 제작하기가 편리한 장점이 있어 철도차량 차체에 적용되기 시작하였다. 보통 중량감소량은 27%에 달하나, 재료비가 알루미늄 압출재에 비해 높기 때문에 차체에 널리 적용되지 못하였다. 본 논문에서는 두 가지 경량화 재질에 대하여 제작 과정을 고찰하고 원가를 분류하여 과거 자료를 기초로한 경제성을 분석하였다. 복합재 차체의 재료비 상승분을 제작의 용이성으로 상쇄할 수 있으며, 대량생산에 따른 장비비를 저감하면 알루미늄 차체에 비해 경쟁력을 가질 수 있음을 알 수 있었다. 지하철 노선의 통계자료를 참고로 하여 중량 감소에 따른 운행 에너지 감소량도 제시하였다.