• Title/Summary/Keyword: Path Theory

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New formula in domination theory and it's application for reliability analysis (Domination이론에서의 새로운 식과 이의 신뢰성계산에 대한 적용)

  • 이광원;이일재;강신재
    • Journal of the Korean Society of Safety
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    • v.11 no.1
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    • pp.16-26
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    • 1996
  • In a series of original papers, [1-17] efficient methods and algorithms have been presented, for the exact solution of many reliability problems represented by binary networks. A starting point of these methods was the concept of domination, firstly introduced in ,elation with reliability problems in [2]. It's application to directed networks resulted in the development of a topological formula for the classical problem of the two terminal reliability. This result was extended later to the all-terminal and the k-terminal reliability problems. All papers mentioned above use a path oriented representation for the network topology. In practical applications, however, it is common and often advantageous to work with cut sets. This article considers the Domination theory for reliability problem of a network. Some topological formula are derived and the power and the application of this formula are shown through the alternative proof of topological formula of A. Satyanarayana [2].

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A hybrid model of regional path loss of wireless signals through the wall

  • Xi, Guangyong;Lin, Shizhen;Zou, Dongyao
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.9
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    • pp.3194-3210
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    • 2022
  • Wall obstruction is the main factor leading to the non-line of sight (NLoS) error of indoor localization based on received signal strength indicator (RSSI). Modeling and correcting the path loss of the signals through the wall will improve the accuracy of RSSI localization. Based on electromagnetic wave propagation theory, the reflection and transmission process of wireless signals propagation through the wall is analyzed. The path loss of signals through wall is deduced based on power loss and RSSI definition, and the theoretical model of path loss of signals through wall is proposed. In view of electromagnetic characteristic parameters of the theoretical model usually cannot be accurately obtained, the statistical model of NLoS error caused by the signals through the wall is presented based on the log-distance path loss model to solve the parameters. Combining the statistical model and theoretical model, a hybrid model of path loss of signals through wall is proposed. Based on the empirical values of electromagnetic characteristic parameters of the concrete wall, the effect of each electromagnetic characteristic parameters on path loss is analyzed, and the theoretical model of regional path loss of signals through the wall is established. The statistical model and hybrid model of regional path loss of signals through wall are established by RSSI observation experiments, respectively. The hybrid model can solve the problem of path loss when the material of wall is unknown. The results show that the hybrid model can better express the actual trend of the regional path loss and maintain the pass loss continuity of adjacent areas. The validity of the hybrid model is verified by inverse computation of the RSSI of the extended region, and the calculated RSSI is basically consistent with the measured RSSI. The hybrid model can be used to forecast regional path loss of signals through the wall.

A Study on Frequency Controlled Bandwidth adjustable Bandpass Filter (주파수제어 대역폭조정 대역통과 여파기에 관한 연구)

  • 최갑석
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.1
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    • pp.18-26
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    • 1975
  • In this paper, a frequency controlled bandwidth adjustable bandpass filter consisting of 4-path system is precented. It is shown that this system has characteristics similar to ihose of the magneticuly coupled double tuned amplifier and the center frequency of the passband is able to be shifted contineolisly. The adjustable range of the bartdwidth of the filter system is anslyzed for she case of the double and single tuned characteristics. The experiment has been conducted to verify the theory of this system and the experimental resulis are in good agreement with the theoretically calculated values.

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Path Analysis of Factors Influencing Career Preparation Behavior of Korean Nursing Students - Based on Social Cognitive Career Theory (간호대학생의 진로행동에 영향을 미치는 요인에 대한 경로 분석- 사회인지 진로이론을 중심으로)

  • Koo, Hyun Young;Park, Ok Kyoung;Jung, Sun Young
    • Child Health Nursing Research
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    • v.23 no.1
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    • pp.10-18
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    • 2017
  • Purpose: The purpose of this study was to identify personal, contextual, and cognitive factors influencing the career preparation behavior of Korean nursing students. In this study, an examination was done of the fitness of a path model for the relationship among these factors based on the social cognitive career theory. Methods: The participants were 413 nursing students in South Korea. Data were collected using self-report questionnaires that included self-esteem, social support, self-efficacy, outcome expectation, career decision level, and career preparation behavior. Data were analyzed using descriptive statistics, Pearson correlation analysis, and path analysis. Results: The factors influencing career preparation behavior were self-efficacy, career decision level, self-esteem, outcome expectation, and social support. The factors influencing career decision level were self-efficacy, outcome expectation, self-esteem, and social support. Conclusion: The findings indicate that self-efficacy is an important factor influencing the career behavior of Korean nursing students. Nurse educators should consider personal, contextual, and cognitive factors of nursing students and develop systemic career guidance programs to help nursing students' career preparation behavior.

A Study on the Target Search Logic in the ASW Decision Support System (대잠전 의사결정지원 시스템에서 표적 탐색 논리 연구)

  • Cho, Sung-Jin;Choi, Bong-Wan;Jeon, Jae-Hyo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.5
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    • pp.824-830
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    • 2010
  • It is not easy job to find a underwater target using sonar system in the ASW operations. Many researchers have tried to solve anti-submarine search problem aiming to maximize the probability of detection under limited searching conditions. The classical 'Search Theory' deals with search allocation problem and search path problem. In both problems, the main issue is to prioritize the searching cells in a searching area. The number of possible searching path that is combination of the consecutive searching cells increases rapidly by exponential function in the case that the number of searching cells or searchers increases. The more searching path we consider, the longer time we calculate. In this study, an effective algorithm that can maximize the probability of detection in shorter computation time is presented. We show the presented algorithm is quicker method than previous algorithms to solve search problem through the comparison of the CPU computation time.

An Empirical Study in Relationship between Franchisor's Leadership Behavior Style and Commitment by Focusing Moderating Effect of Franchisee's Self-efficacy (가맹본부의 리더십 행동유형과 가맹사업자의 관계결속에 관한 실증적 연구 - 가맹사업자의 자기효능감의 조절효과를 중심으로 -)

  • Yang, Hoe-Chang;Lee, Young-Chul
    • Journal of Distribution Research
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    • v.15 no.1
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    • pp.49-71
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    • 2010
  • Franchise businesses in South Korea have contributed to economic growth and job creation, and its growth potential remains very high. However, despite such virtues, domestic franchise businesses face many problems such as the instability of franchisor's business structure and weak financial conditions. To solve these problems, the government enacted legislation and strengthened franchise related laws. However, the strengthening of laws regulating franchisors had many side effects that interrupted the development of the franchise business. For example, legal regulations regarding franchisors have had the effect of suppressing the franchisor's leadership activities (e.g. activities such as the ability to advocate the franchisor's policies and strategies to the franchisees, in order to facilitate change and innovation). One of the main goals of the franchise business is to build cooperation between the franchisor and the franchisee for their combined success. However, franchisees can refuse to follow the franchisor's strategies because of the current state of franchise-related law and government policy. The purpose of this study to explore the effects of franchisor's leadership style on franchisee's commitment in a franchise system. We classified leadership styles according to the path-goal theory (House & Mitchell, 1974), and it was hypothesized and tested that the four leadership styles proposed by the path-goal theory (i.e. directive, supportive, participative and achievement-oriented leadership) have different effects on franchisee's commitment. Another purpose of this study to explore the how the level of franchisee's self-efficacy influences both the franchisor's leadership style and franchisee's commitment in a franchise system. Results of the present study are expected to provide important theoretical and practical implications as to the role of franchisor's leadership style, as restricted by government regulations and the franchisee's self-efficacy, which could be needed to improve the quality of the long-term relationship between the franchisor and franchisee. Quoted by Northouse(2007), one problem regarding the investigation of leadership is that there are almost as many different definitions of leadership as there are people who have tried to define it. But despite the multitude of ways in which leadership has been conceptualized, the following components can be identified as central to the phenomenon: (a) leadership is a process, (b) leadership involves influence, (c) leadership occurs in a group context, and (d) leadership involves goal attainment. Based on these components, in this study leadership is defined as a process whereby franchisor's influences a group of franchisee' to achieve a common goal. Focusing on this definition, the path-goal theory is about how leaders motivate subordinates to accomplish designated goals. Drawing heavily from research on what motivates employees, path-goal theory first appeared in the leadership literature in the early 1970s in the works of Evans (1970), House (1971), House and Dessler (1974), and House and Mitchell (1974). The stated goal of this leadership theory is to enhance employee performance and employee satisfaction by focusing on employee motivation. In brief, path-goal theory is designed to explain how leaders can help subordinates along the path to their goals by selecting specific behaviors that are best suited to subordinates' needs and to the situation in which subordinates are working (Northouse, 2007). House & Mitchell(1974) predicted that although many different leadership behaviors could have been selected to be a part of path-goal theory, this approach has so far examined directive, supportive, participative, and achievement-oriented leadership behaviors. And they suggested that leaders may exhibit any or all of these four styles with various subordinates and in different situations. However, due to restrictive government regulations, franchisors are not in a position to change their leadership style to suit their circumstances. In addition, quoted by Northouse(2007), ssubordinate characteristics determine how a leader's behavior is interpreted by subordinates in a given work context. Many researchers have focused on subordinates' needs for affiliation, preferences for structure, desires for control, and self-perceived level of task ability. In this study, we have focused on the self-perceived level of task ability, namely, the franchisee's self-efficacy. According to Bandura (1977), self-efficacy is chiefly defined as the personal attitude of one's ability to accomplish concrete tasks. Therefore, it is not an indicator of one's actual abilities, but an opinion of the extent of how one can use that ability. Thus, the judgment of maintain franchisee's commitment depends on the situation (e.g., government regulation and policy and leadership style of franchisor) and how it affects one's ability to mobilize resources to deal with the task, so even if people possess the same ability, there may be differences in self-efficacy. Figure 1 illustrates the model investigated in this study. In this model, it was hypothesized that leadership styles would affect the franchisee's commitment, and self-efficacy would moderate the relationship between leadership style and franchisee's commitment. Theoretically, quoted by Northouse(2007), the path-goal approach suggests that leaders need to choose a leadership style that best fits the needs of subordinates and the work they are doing. According to House & Mitchell (1974), the theory predicts that a directive style of leadership is best in situations in which subordinates are dogmatic and authoritarian, the task demands are ambiguous, and the organizational rule and procedures are unclear. In these situations, franchisor's directive leadership complements the work by providing guidance and psychological structure for franchisees. For work that is structured, unsatisfying, or frustrating, path-goal theory suggests that leaders should use a supportive style. Franchisor's Supportive leadership offers a sense of human touch for franchisees engaged in mundane, mechanized activity. Franchisor's participative leadership is considered best when a task is ambiguous because participation gives greater clarity to how certain paths lead to certain goals; it helps subordinates learn what actions leads to what outcome. Furthermore, House & Mitchell(1974) predicts that achievement-oriented leadership is most effective in settings in which subordinates are required to perform ambiguous tasks. Marsh and O'Neill (1984) tested the idea that organizational members' anger and decline in performance is caused by deficiencies in their level of effort and found that self-efficacy promotes accomplishment, decreases stress and negative consequences like depression and emotional instability. Based on the extant empirical findings and theoretical reasoning, we posit positive and strong relationships between the franchisor's leadership styles and the franchisee's commitment. Furthermore, the level of franchisee's self-efficacy was thought to maintain their commitment. The questionnaires sent to participants consisted of the following measures; leadership style was assessed using a 20 item 7-point likert scale developed by Indvik (1985), self-efficacy was assessed using a 24 item 6-point likert scale developed by Bandura (1977), and commitment was assessed using a 6 item 5-point likert scale developed by Morgan & Hunt (1994). Questionnaires were distributed to Korean optical franchisees in Seoul. It took about 20 days to complete the data collection. A total number of 140 questionnaires were returned and complete data were available from 137 respondents. Results of multiple regression analyses testing the relationships between the each of the four styles of leadership shown by the franchisor as independent variables and franchisee's commitment as the dependent variable showed that the relationship between supportive leadership style and commitment ($\beta$=.13, p<.001),and the relationship between participative leadership style and commitment ($\beta$=.07, p<.001)were significant. However, when participants divided into high and low self-efficacy groups, results of multiple regression analyses showed that only the relationship between achievement-oriented leadership style and commitment ($\beta$=.14, p<.001) was significant in the high self-efficacy group. In the low self-efficacy group, the relationship between supportive leadership style and commitment ($\beta$=.17, p<.001),and the relationship between participative leadership style and commitment ($\beta$=.10, p<.001) were significant. The study focused on the franchisee's self-efficacy in order to explore the possibility that regulation, originally intended to protect the franchisee, may not be the most effective method to maintain the relationships in a franchise business. The key results of the data analysis regarding the moderating role of self-efficacy between leadership behavior style as proposed by path-goal and commitment theory were as follows. First, this study proposed that franchisor should apply the appropriate type of leadership behavior to strengthen the franchisees commitment because the results demonstrated that supportive and participative leadership styles by the franchisors have a positive influence on the franchisee's level of commitment. Second, it is desirable for franchisor to validate the franchisee's efforts, since the franchisee's characteristics such as self-efficacy had a substantial, positive effect on the franchisee's commitment as well as being a meaningful moderator between leadership and commitment. Third, the results as a whole imply that the government should provide institutional support, namely to put the franchisor in a position to clearly identify the characteristics of their franchisees and provide reasonable means to administer the franchisees to achieve the company's goal.

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An Overstress Model for Non-proportional Loading of Nylon 66 (Nylon 66의 무비례 하중에 대한 과응력 모델)

  • Ho, Gwang-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.12
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    • pp.2056-2061
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    • 2001
  • Non-proportional loading tests of Nylon 66 at room temperature exhibit path dependent behavior and plasticity-relaxation interactions. The uniaxial formulation of the viscoplasticity theory based on overstress (VBO), which has been used to reproduce the nonlinear strain rate sensitivity, relaxation, significant recovery and cyclic softening behaviors of Nylon 66, is extended to three-dimensions to predict the response in strain-controlled, comer-path tests. VBO consists of a flow law that is easily written for either the stress or the strain as the independent variable. The flow law depends on the overstress, the difference between the stress and the equilibrium stress that is a state variable in VBO. The evolution law of the equilibrium stress in turn contains two additional state variables, the kinematic stress and the isotropic stress. The simulations show that the constitutive model is competent at modeling the deformation behavior of Nylon 66 and other solid polymers.

Nonsteady Plane-strain ideal forming with elastic dead zone (탄성 변형 영역을 고려한 비정상 평면 변형 이상 공정 이론)

  • Lee W.;Chung K.;Richmond Owen
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.190-193
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    • 2004
  • Ever since the ideal forming theory has been developed fur process design purposes, application has been limited to sheet forming and, for bulk forming, to two-dimensional steady flow. Here, application for the non-steady case was performed under the plane-strain condition based on the theory previously developed. In the ideal flow, material elements deform following the minimum plastic work path (or mostly proportional true strain path) so that the ideal plane-strain flow can be effectively described using the two-dimensional orthogonal convective coordinate system. Besides kinematics, for a prescribed final part shape, schemes to optimize a preform shape out of a class of initial configurations and also to define the evolution of shapes and boundary tractions were developed. Discussions include the two problematic issues on internal tractions and the non-monotonous straining. For demonstration purposes, numerical calculations were made for a bulk part under forging.

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A STREE-STRAIN THEORY FOR COMPACTED ROCKFILL (다짐된 사약재료의 응력-변형 이론)

  • 이영희
    • Geotechnical Engineering
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    • v.3 no.1
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    • pp.77-96
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    • 1987
  • Based on observation emerged from the undrained tests and the anisotropic consolidation tests, an incremental stress-strain theory for rockfill is proposed in a manner similar to that developed ky Cambridge Group for normally consolidated soils; the volumetric strain due to stress increment is the same as the increment due to an undrained component followed by an increment along the constant stress ratio path. The strains in drained tests are predicted from those in the undrained tests and in the anisotropic consolidation tests. An expression for the undrained stress path is derived based on the bilinear relationship between the pore pressure developed and the stress ratio observed during untrained tests. Good agreement is found between the calculated and measured strains. This trend in behaviour would be helpful in establishing a stress.strain model for rockfill using the elasto-plastic behaviour with the concept of plastic potentials and flow rules.

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The Attachment Between Mother and Married Son and Mother's Marital Relationship to Son's Marital Satisfaction: A Path Model (모자간의 애착 및 모의 결혼관계에 따른 아들 부부의 결혼만족도 : 인과적 모형)

  • 유은희
    • Journal of the Korean Home Economics Association
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    • v.27 no.2
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    • pp.149-162
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    • 1989
  • Based on attachment theory and family system theory, this study was attempted to construct a path model in which showed how adult son-mother relationship and mother's marital relationship influence son's marital satifaction. Predictor variables examined were the attachment between mother and married son, mother's dependency, mother's marital relationship, son's filial obligation, son's marriage years. Data were analyzed from survey and structured interviews conducted with 111 families including married son, his wife and his mother. Results indicated that the attachment between mother and married son influenced directly to son's marital satisfaction while the other variables had an indirect influence via the attachment between mother and son. The importance of the relationship between mother and married son to son's marital satisfaction received string support.

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