• Structural Engineering and Mechanics
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• 제29권2호
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• pp.187-201
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• 2008

Earthquake induced hysteretic energy demand for a structure can be used as a limiting value of a certain performance level in seismic design of structures. In cases where it is larger than the hysteretic energy dissipation capacity of the structure, failure will occur. To be able to select the limiting value of hysteretic energy for a particular earthquake hazard level, it is required to define the variation of hysteretic energy in terms of probabilistic terms. This study focuses on the probabilistic evaluation of earthquake induced worst failure probability and approximate confidence intervals for inelastic single-degree-of-freedom (SDOF) systems with a typical steel moment connection based on hysteretic energy. For this purpose, hysteretic energy demand is predicted for a set of SDOF systems subject to an ensemble of moderate and severe EQGMs, while the hysteretic energy dissipation capacity is evaluated through the previously published cyclic test data on full-scale steel beam-to-column connections. The failure probability corresponding to the worst possible case is determined based on the hysteretic energy demand and dissipation capacity. The results show that as the capacity to demand ratio increases, the failure probability decreases dramatically. If this ratio is too small, then the failure is inevitable.

• Smart Structures and Systems
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• 제33권1호
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• pp.27-39
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• 2024

The effectiveness of conventional tuned liquid dampers (TLDs) in controlling the wind-induced response of tall flexible structures has been indicated. However, the impaired control effect in the detuning condition or a considerably high mass cost of liquid may be incurred in ensuring the high-level serviceability. To provide an efficient TLD-based solution for wind-induced vibration control, this study proposes a serviceability-oriented optimal design method for isolated TLDs (ILDs) and derives analytical design formulae. The ILD is implemented by mounting the TLD on the linear isolators. Stochastic response analysis is performed for the ILD-equipped structure subjected to stochastic wind and white noise, and the results are considered to derive the closed-form responses. Correspondingly, an extensive parametric analysis is conducted to clarify a serviceability-oriented optimal design framework by incorporating the comfort demand. The obtained results show that the high-level serviceability demand can be satisfied by the ILD based on the proposed optimal design framework. Analytical design formulae can be preliminarily adopted to ensure the target serviceability demand while enhancing the structural displacement performance to increase the safety level. Compared with conventional TLD systems, the ILD exhibits higher effectiveness and a larger frequency bandwidth for wind-induced vibration control at a small mass ratio.

• 대한교통학회지
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• 제24권4호
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• pp.7-17
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• 2006

현재 교통수요예측 기법은 주로 외생적인 변수에 의해 추정된 종속적 차원의 수요만을 고려할 뿐 도로의 개선으로 인해 새롭게 유발/생성되는 수요(유발통행수요)는 충분히 고려되지 않고 있으며. 관련 연구도 국내에서는 아직 미미한 실정이다 본 연구는 이와 같은 유발통행수요 추정 앞서 필요한 연구로 도로의 개선과 집합적 개념의 유발통행수요와의 관련성을 검증하고 차후 유발통행수요 추정에 적용될 수 있는 현실적인 수요탄력성 원단위를 수도권의 각 지역과 통행목적별로 추정하는데 그 목적이 있다 이를 위해 2002년 서울시 가구통행실태조사 자료와 네트워크 자료를 이용하여 단위통행시간에 대한 수요탄력성 원단위를 지역별로 산출하였고 지역별로 산출된 수요탄력성은 서울시 -0.582, 인천시 -0.597, 경기도 -0.559로 1995년 NPTS 자료로 산출된 수요탄력성 $-0.3{\sim}-0.5$보다 조금 높게 나타났다 본 분석 결과를 통해 우리나라의 통행자가 미국 통행자보다 통행시간에 대해 더 탄력적이며 도로의 개선으로 인해 유발될 수 있는 수요가 더 많은 것으로 나타났다. 추가적으로 거시적 관점에서 교통관리방안과 교통정책을 고찰해 볼 수 있는 요일별/연령별 수요탄력성 원단위를 산출하여 그 의미에 대해서 살펴보았다.

• 한국통신학회논문지
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• 제37권8C호
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• pp.741-749
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• 2012

스마트폰 도입 이후 국내 무선인터넷 시장은 획기적으로 변화하여 왔다. 이에 따라 무선인터넷시장의 성장은 물론 무선데이터 트래픽 또한 기하급수적으로 증가하고 있다. 이러한 무선인터넷 시장 및 트래픽 증가 현상에 대해 다양한 찬반양론은 있으나, 무선인터넷 서비스 시장의 활성화는 그간 성장이 다소 정체되어 왔던 통신시장의 재도약의 발판을 마련하고 있는 것은 부정할 수 없는 사실이다. 이에 본 연구는 사건연구(Event Study) 방법론을 이용하여 망 전송 속도 및 네트워크 용량 확대에 따라 발생가능한 수요 패턴 중 하나인 유도된 수요(Induced Demand)가 LTE 도입에 따라 실제 통신시장에서도 발생하고 있는 지를 실증적으로 분석하고, 유도된 수요 발생에 따른 문제점 및 정책적 해결 방안을 제시하고자 한다.

• 보건행정학회지
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• 제24권1호
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• pp.13-23
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• 2014

Background: A need arises to efficiently control health expenditure for medical aid due to a sharp increase in medical aid expenditure. This study experimently analyzes the impact of physician behavior on medical use for medical aid beneficiaries using supplier induced demand (SID) theory. Methods: This study looks into analyze SID effect using expenditure factor analysis of medical aid for the years between 2003 and 2010 in comparison with health insurance. Moreover, this study analyzes the existence and scale of SID using econometrics modeling with panel data on 16 cities and provinces's health expenditure data for medical aid from 2003 1/4 to 2010 4/4. Results: This study finds that the growth rate of visit days per capita and treatment amount per visit days for medical aid is higher than health insurance. Furthermore, the result of econometrics modeling analysis shows the existence of SID in general hospital, hospital, clinic, oriental clinic. Conclusion: In order to efficiently control expenditure for medical aid, it is required to reinforce macro polices such as the introduction of 'target management' and micro policies such as the strengthen of management on medical institutes in the perspective of suppliers as well as regulations of demanders.

• Smart Structures and Systems
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• 제14권3호
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• pp.445-468
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• 2014

The objective in this research is to determine the feasibility of using changes on the dynamic properties of a reinforced concrete (RC) structure to identify different levels of seismic induced damage. Damping ratio and natural frequency changes in a RC bridge column are analyzed using different signal processing techniques like Hilbert Transforms, Random Decrement and Wavelet Transforms. The data used in the analysis was recorded during a full-scale RC bridge column shake table test. The structure was subjected to ten earthquake excitations that induced different levels of inelastic demand on the column. In addition, low-intensity white noises were applied to the column in-between earthquakes. The results obtained show that the use of the damping ratio and natural frequency of vibration as damage indicators is arguable.

• 한국응급구조학회지
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• 제6권1호
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• pp.77-86
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• 2002

The purposes of this research which was conducted by surveying lost/added unit hours reports, unit hour demand analysis worksheets from prehospital care reports of two squads in Kyonggi Provincial Fire and Disaster Headquarters for 20 weeks (January 1, 2002 - May 20, 2002) are to get Unit Hour Utilizations. Call Demands such as Unit Hour Demand, Simple Average Demand, High Average Demand, Peak Average Demand, the High Actual Demand. The conclusions from this analysis were summarized as follows: (1) By revealing Unit Hour Produced 3223.9, Call Volume 964, Unit Hour Utilization 0.299 at the Squad A and Unit Hour Produced 3328.4, Call Volume 901, Unit Hour Utilization 0.271 at the Squad B induced Korean Squads to chance identification, definition, direction of Unit Hour Utilization. (2) By revealing Simple Average Demand 7.4 on Monday Tuesday, High Average Demand 9.6 on Tuesday Friday. Peak Average Demand 11.5 on Tuesday, the High Actual Demand 12 on Tuesday Wednesday at the Squad A and Simple Average Demand 6.8 on Sunday, High Average Demand 10.4 on Monday, Peak Average Demand 11.5 on Monday, the High Actual Demand 13 on Monday at the Squad B enabled Korean Squads to utilize System Status Management. (3) The Maximum Calls per Unit Hour were 115 for 23:00~23:59, the Minimum Calls per Unit Hour were 46 for 05:00~05:49 in two squads. The Maximum Calls per Unit Hour were 7.4 on Tuesday Saturday, the Minimum Calls per Unit Hour were 6.1 on Thursday at the Squad A. The Maximum Calls per Unit Hour were 7.3 on Monday Saturday, the Minimum Calls per Unit Hour were 5.6 on Thursday at the Squad B. (4) Analyzing demand for EMTs in the optimum emergency medical service of Korea, we have been able to utilize this Unit Hour Utilization in company with the established estimation methods such as international comparisons or the number of ambulances for scientific reasonable estimation. (5) These Call Demands which were limited to the demand time in this study will make us expect some following studies including demand time, demand time, demand map for Strategic Deployment.

• 대한전기학회논문지:전력기술부문A
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• 제54권2호
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• pp.79-87
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• 2005

At present Cournot model is one of the most commonly used theories to analyze the gaming situation in oligopoly market. But there exist several problems to apply this model to electricity market. The representative one is to obtain the inverse demand curve able to be induced from the relationship between market price and demand response. In Cournot model, each player offers their generation quantity to accomplish maximum profit, which is accomplished by reducing their quantity compared with available total capacity. As stated above, to obtain the probable Cournot equilibrium to reflect real market situation, we have to induce the correct demand function first of all. Usually the correlation between price and demand appears on the long-term basis through the statistical data analysis (for example, regression analysis) or by investigating consumer utility functions of several consumer groups classified as residential, industrial, and commercial. However, the elasticity has a tendency to change continuously according to the total market demand size or the level of market price. Therefore it should be updated as trading period passes by. In this paper we propose a method for inducing and updating this price elasticity of demand function for more realistic market equilibrium.

• KIEE International Transactions on Power Engineering
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• 제5A권4호
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• pp.403-411
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• 2005

At present, the Cournot model is one of the most commonly used theories to analyze the gaming situation in an oligopoly type market. However, several problems exist in the successful application of this model to the electricity market. The representative one is obtaining the inverse demand curve able to be induced from the relationship between market price and demand response. In the Cournot model, each player offers their generation quantity to obtain maximum profit, which is accomplished by reducing their quantity compared with available total capacity. As stated above, to obtain the probable Cournot equilibrium to reflect the real market situation, we have to induce the correct demand function first of all. Usually the correlation between price and demand appears over the long-term through statistical data analysis (for example, regression analysis) or by investigating consumer utility functions of several consumer groups classified as residential, industrial, and commercial. However, the elasticity has a tendency to change continuously according to the total market demand size or the level of market price. Therefore it should be updated as the trading period passes by. In this paper we propose a method for inducing and updating this price elasticity of demand function for more realistic market equilibrium.

• 아태비즈니스연구
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• 제15권1호
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• pp.239-256
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• 2024

Purpose - The purpose of this study was to examine the main determinants of the gap between housing demand and house affordability. Design/methodology/approach - This study used the micro-level data of 60,043 households from Korea Housing-Finance Corporation by covering the period 2011 to 2022. Findings - First, the trend of general housing demand showed a higher figure in the future demand than in current demand. And such a tendency showed in all types of households, a relative young, low income, and single households. In the case of current housing demand, it has increased by 2022 from the beginning of 2013, while the future demand has rapidly increased from 2020. Second, although the house affordability showed a higher figure in current housing demand by 2019, its trend changed to be higher in future housing demand from 2020 by a rapid decreasing affordbility in current demand. In the case of young householders, the current house affordability was higher than that of future. The figure of low income householders was below 1 point in both periods, and house affordability of single householders showed a similar level in both periods. which showed over 1 point. Third, financial regulation on housing markets induced th widening of the gap between housing demand and house affordability, and such a trend is much atronger in the future(potential) gap of demand and affordability. More specifically, the strengthen financial regulation leaded to the widening of the gap in all types of households, a relative young, low income, and single households. Research implications or Originality - The effect of financial regulation is necessary to consider under the features of each households.