• Geomechanics and Engineering
• /
• 제14권6호
• /
• pp.571-580
• /
• 2018

The failure mechanism of tunnel roof is investigated with upper bound theorem of limit analysis. The stochastic settlement and nonlinear failure criterion are considered in the present analysis. For the collapse of tunnel roof, the surface settlement is estimated by the simplified stochastic medium theory. The failure curve expressions of collapse blocks in homogeneous and in layered soils are derived, and the effects of material parameters on the potential range of failure mechanisms are discussed. The results show that the material parameters of initial cohesion, nonlinear coefficient and unit weight have significant influences on the potential range of collapse block in homogeneous media. The proportion of collapse block increases as the initial cohesion increases, while decreases as the nonlinear coefficient and the unit weight increase. The ground surface settlement increases with the tunnel radius increasing, while the possible collapse proportion decreases with increase of the tunnel radius. In layered stratum, the study is investigated to analyze the effects of material parameters of different layered media on the proportion of possible collapse block.

• 한국사회복지학회:학술대회논문집
• /
• 한국사회복지학회 2004년도 춘계학술대회 자료집
• /
• pp.757-779
• /
• 2004

The purpose of study is to provide efficient initial approaches for counseling in social work practice settings. First, it attempts to identify the correlation between the Myers-Brigg's Type Indicator(MBTI), a personality index based on the theory of psychological typology, and Personality Adaptation Types(PAT) models. Second, it attempts to develop a counseling method which can be applied to the initial interview, using the paradigm of door to therapy such as "Open Door", "Target Door", and "Trap Door" based on the PAT theory. The result of the quantitative study showed the correlation between MBTI and PAT as follows: MBTI Extrovert and Feeling(E, F) type was statistically correlated to hysterical PAT. MBTI Extrovert, Intuition and Perceiving(E, N, P) type was statistically correlated to Obsessive-Compulsive PAT. In conclusion, this study finds that when a clinical social worker approaches a client with the client's MBTI personality type and an interventional personality adaptation theory approach such as "Open Door", "Target Door", or "Trap Door", the efficiency of communication is increased significantly.

• 한국세라믹학회지
• /
• 제54권5호
• /
• pp.443-447
• /
• 2017

The initial reaction of hexachlorodisilane ($Si_2Cl_6$, HCDS) on amorphous silica ($SiO_2$) surface for atomic layer deposition was investigated using density functional theory. Two representative reaction sites on the amorphous $SiO_2$ surface for HCDS reaction, a surface hydroxyl and a two-membered ring, were considered. The reaction energy barrier for HCDS on both sites was higher than its adsorption energy, indicating that it would desorb from the surface rather than react with the surface. At high temperature range, some HCDSs can have kinetic energy high enough to overcome the reaction energy barrier. The HCDS reaction on top of the reacted HCDS was investigated to confirm its self-limiting characteristics.

• 한국IT서비스학회지
• /
• 제9권4호
• /
• pp.1-18
• /
• 2010

Plural governance system in which firms use vertical integration and market governance simultaneously are widely used across various marketing context. Typical examples of plural governance include franchise systems, in which firms own and operate some unit themselves while licensing the operation of some of their units to franchisees. Despite many scholars have attempted to explore the structure of plural governance over decades, there are few insights into its determinants. In this study, we examine the relationship between the proportion of outlets franchised and several franchisor's characteristics based on the perspectives of transaction cost analysis, resource scarcy theory and agency theory. Using franchisor data in Korean Franchise Disclosure Document over the 2006-2009 period, we test the effect of franchisor size, system growth rate, franchise fee, initial investment, and risk sharing on the proportion of outlets franchised. Except for the effect of system growth rate, the results of a series of multiple regression analysis supported the negative effects of franchisor size, franchise fee, initial investment and risk sharing on the proportion of outlets franchised.

• Journal of the Korean Wood Science and Technology
• /
• 제26권4호
• /
• pp.13-19
• /
• 1998

Stress relaxation tests have been performed under five different tensile strain levels and five different bending strain levels. Three different theoretical models have been developed based on four-element Burger's model, viscoelastic theory and viscous-viscoelastic theory. Experimental data were used to obtain parameters of the models and to verify accuracy of the models. Among the three theoretical models developed in this study, three-integral model (Model 3) based on viscous-viscoelastic theory showed the most exact estimations of stress relaxation under both tensile and bending strains and their correlation coefficients were greater than 0.99 for all the strain levels. Model 1 showed little initial stress relaxation. Model 2 showed excessive initial relaxation and, then, no relaxation after about 20 minute of strain application. Stress retention under strain decreased as strain increased, which means increased stress relaxation as strain increases. When the strain level was less than proportional limit, the effect of strain level on stress relaxation was not clearly shown. However, this effect was increased as strain level increased when strain level was greater than proportional limit.

• 대한기계학회논문집
• /
• 제10권3호
• /
• pp.419-426
• /
• 1986

본 연구에서는 가공삭도의 선로설계에 최적화기법을 도입하여 시행착오법보다 신속.정확하면서도 경제성이나 승차감등이 항상된 설계를 위한 절차를 개발하고자 한 다. 이를 위하여 먼저 본 논문에서는 설계에 적용될 선로의 기본이론들을 정리, 혹 은 유도 하였다. 특히 기존의 포물곡선이론의 정확성을 규명하기 위하여 엄밀해인 현수곡선이론을 여러경우에 대하여 유도하고 그 오차를 계산하였다. 계산된 오차는 오차해석을 통하여 추측 될 수 있었으며 본 연구에서는 정의된 무차원군들과의 연관 성도 검토되었다.

• 한국수학사학회지
• /
• 제23권3호
• /
• pp.107-119
• /
• 2010

확률 개념과 지식이 정립되는 단계에서 중요한 의의를 가졌던 기댓값이 확률의 역사에서 초기에 역사적으로 어떻게 다루어졌는가를 알아보는 것은 의미 있는 일이다. 이에 본 연구에서는 기댓값의 개념과 정의가 변화하고 정선되어 온 역사적 과정에서 이 발전에 기여한 몇 가지 문제와 함께 그 문제의 해결 과정을 알아봄으로써 확률에서 기댓값의 의미를 다시 한번 고찰해 보고자 한다.

• Structural Engineering and Mechanics
• /
• 제61권3호
• /
• pp.381-387
• /
• 2017

In this paper we investigate the theory of micropolar thermoelastic bodies whose micro-particles possess microtemperatures. We transform the mixed initial boundary value problem into a temporally evolutionary equation on a Hilbert space and after that we prove the existence and uniqueness of the solution. We also approach the study of the continuous dependence of solution upon initial data and loads.

• Structural Engineering and Mechanics
• /
• 제53권6호
• /
• pp.1201-1214
• /
• 2015

This paper introduces the combined effect of electric field, magnetic field and thermal field on edge wave propagating in a homogeneous isotropic prestressed plate of finite thickness and infinite length. The dispersion relation of edge wave has been obtained by using classical dynamical theory of thermoelasticity. The phase velocity has been computed and shown graphically for various initial stress parameter, electro-magneto parameter, electric parameter and thermoelastic coupling parameter.

• 제어로봇시스템학회논문지
• /
• 제10권12호
• /
• pp.1241-1248
• /
• 2004

A controller of wheeled mobile robot(WMR) based on Lyapunov theory is designed and a Fuzzy-Neural Network algorithm is applied to this system to adjust controller gain. In conventional controller of WMR that adopts fixed controller gain, controller can not pursuit trajectory perfectly when initial condition of system is changed. Moreover, acquisition of optimal value of controller gain due to variation of initial condition is not easy because it can be get through lots of try and error process. To solve such problem, a Fuzzy-Neural Network algorithm is proposed. The Fuzzy logic adjusts gains to act up to position error and position error rate. And, the Neural Network algorithm optimizes gains according to initial position and initial direction. Computer simulation shows that the proposed Fuzzy-Neural Network controller is effective.