• 대한교통학회지
• /
• 제7권2호
• /
• pp.45-52
• /
• 1989

The network equilibrium theory is to estimate the travel choices on a transportation network when the resulting travel times and costs are one basis for the choices. Increasing use of this principle on travel assignment problem lead to develop the combined choice models including not only travel options such as mode and route, but location options like trip distribution problems. This paper, first, reviews earlier developments of variable demand network equilibrium models, combined modeles of trip distribution and assignment, and entropy constrained combined models. Then various model structures of combining travel choice models based on network equilibrium theory and entropy constraints are discussed.

• 천문학논총
• /
• 제30권2호
• /
• pp.309-313
• /
• 2015

If the present universe is slightly open then pre-inflation curvature would appear as a cosmic dark-flow component of the CMB dipole moment. We summarize current cosmological constraints on this cosmic dark flow and analyze the possible constraints on parameters characterizing the pre-inflating universe in an inflation model with a present-day very slightly open ${\Lambda}CDM$ cosmology. We employ an analytic model to show that for a broad class of inflation-generating effective potentials, the simple requirement that the observed dipole moment represents the pre-inflation curvature as it enters the horizon allows one to set upper and lower limits on the magnitude and wavelength scale of pre-inflation fluctuations in the inflaton field and the curvature parameter of the pre-inflation universe, as a function of the fraction of the total initial energy density in the inflaton field. We estimate that if the current CMB dipole is a universal dark flow (or if it is near the upper limit set by the Planck Collaboration) then the present constraints on ${\Lambda}CDM$ cosmological parameters imply rather small curvature ${\Omega}_k{\sim}0.1$ for the pre-inflating universe for a broad range of the fraction of the total energy in the inflaton field at the onset of inflation. Such small pre-inflation curvature might be indicative of open-inflation models in which there are two epochs of inflation.

• Asia pacific journal of information systems
• /
• 제32권1호
• /
• pp.92-124
• /
• 2022

Providing services using kiosks is actively carried out between suppliers and consumers. These service processes have recently begun to play a dominant role in transactions. However, previous self-service technology (SST) studies or kiosks have not fully reflected the changing environment surrounding these different technologies. To cover the updated business environments, we combined qualitative and quantitative research methods. Through qualitative research and a review of previous studies, the variables emphasized as motivations and constraints for kiosks use and those that can be newly illuminated were selected for this study. We then applied the variables to the research model to assess their influence. In terms of the motivations for using kiosks, the results suggest that perceived usefulness and compatibility as service quality, forced use, and perceived service providers' efficiency as provider polices, absorptive capacity, and habit as an individual characteristic and social influence as a subjective norm have a significant effect on the attitude toward kiosks. In terms of constraints, difficult to use and need for interaction predicts the attitude toward kiosks. Attitude toward kiosks, perceived behavioral control, and social influence are directly related to the intention to use kiosks. Lastly, intention to use kiosks plays a significant role as an antecedent of revisit intention. Using these empirical results, we propose both academic and practical implications for future kiosks use.

• 한국컴퓨터정보학회논문지
• /
• 제16권3호
• /
• pp.53-63
• /
• 2011

XML 데이터를 효율적으로 저장하고 질의하기 위하여 많은 기법들이 제안되었다. 이러한 목표를 위한 한 가지 방법은 XML 데이터를 관계형 형식으로 변환하여 관계형 데이터베이스를 사용하는 것이다. XML 문서의 내용, 구조, 의미 정보인 제약조건 보존은 스키마를 변환하는 과정에서 매우 중요하다. 특히 키 제약조건은 데이터베이스 이론의 중요한 부분을 차지한다. 따라서 제안된 기법은 주키와 외래키를 표현함으로써 XML의 의미를 반영하며, 변환하는 데에 XML 데이터의 키 제약조건뿐만 아니라 데이터의 내용과 구조와 의미도 보존한다. 변환 정보는 문서의 내용, 문서의 구조(부모-자식 관계), 함수적 종속성, XML key와 keyref 제약조건에 의해 포착한 문서의 의미이다. 제안된 기법은 XML 스키마를 변환할 때에 의미적 제약조건들의 보존을 보장함으로써 관계형 데이터베이스에서 데이터 무결성을 보장하기 위한 저장 프로시저나 트리거를 사용할 필요가 없는 이점이 있다. 이러한 변환은 산업체에서 필요한 데이터 관리의 한 부분으로, 이미 웹에 저장되어있는 데이터를 데이터베이스에 저장하여 다른 업무에 활용할 수가 있을 것이다. 본 논문에서는 DTD에서 지원하는 ID/IDREF 키, 상속 관계, 묵시적 참조 무결성은 반영하지 못하였다.

• 시스템엔지니어링워크숍
• /
• 통권4호
• /
• pp.151-154
• /
• 2004

This paper presents the general system theory and its applications to the safety analysis method that is a recent trend over the traditional event-driven model. This new model is known as STAMP(Systems Theory Accident Modeling and Process)proposed by Nancy G. Leveson in MIT. The new model has benefits of systemic approaches concerning the system safety as a whole including the context it is in, its stimulants and outcomes, and its parts as well as the relationships among them in a holistic manner. The method consists of a hierarchical control structure, a process model, and the safety constraints governing the control. This paper demonstrates an example the contrasts the differences between the approaches of STAMP and the traditional safety models.

• 한국소음진동공학회논문집
• /
• 제11권7호
• /
• pp.275-286
• /
• 2001

The research presents an analytical theory to calculate the characteristics of the bal bearing with waviness in its rolling elements considering the centrifugal force and gyroscopic moment of bal. The effects of centrifugal force and gyroscopic moment are introduced to the kinematic constraints and force equilibrium equations. and the waviness of rolling elements is modeled by sinusoidal function to calculate the contact force at each ball. The numerical solutions of governing equation of berating due to waviness are calculated by using the Newton-Raphson method. The accuracy of the research is validated by comparing the contact force. contact angle in case of considering the centrifugal force and gyroscopic moment of bal and the contact force and vibration frequencies in cases of considering waviness with the prior researches respectively. It investigates the stiffness, contact force. displacement and vibration frequencies of the ball bearing considering not only the centrifugal force and gyroscopic moment of ball but also the waviness of the rolling elements.

• 시스템엔지니어링학술지
• /
• 제1권1호
• /
• pp.20-25
• /
• 2005

This paper presents the general system theory and its applications to the safety analysis method that is a recent trend over the traditional event-driven model. This new model is known as STAMP(Systems Theory Accident Modeling and Process) proposed by Nancy G. Leveson in MIT. The new model has benefits o f systemic approaches concerning the system safety as a whole including the context it is in, its stimulants and outcomes, and its parts as well as the relationships among them in a holistic manner. The method consists of a hierarchical control structure, a process model, and the safety constraints governing the control. This paper demonstrates an example that contrasts the differences between the approaches of STAMP and the traditional safety models.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
• /
• pp.343-346
• /
• 1998

This paper deals with the decision in vague knowledge, One method is a classic theory. That is to say, constraints and goals in the vague knowledge. Another method is the fuzzy catastrophe. If there exist two fuzzy variables, there may be a discontinuity which plays an important role in decision.

• 한국전자거래학회지
• /
• 제10권1호
• /
• pp.61-80
• /
• 2005

업무프로세스관리(BPM) 시스템은 업무프로세스의 효율적인 실행, 통제 및 관리를 지원하는 소프트웨어 시스템으로서, 복잡한 프로세스를 자동화하고, 이를 효과적으로 관리하여 기업의 생산성 향상에 기여한다. 그러나, 상용시스템은 주로 프로세스의 자동화에 초점을 두고 있어 프로세스와 업무참여자 관점에서 효율적인 관리 방법을 제공하지 못하고 있다. 따라서, BPM 시스템은 프로세스 참여자와 전체 프로세스 효율성 향상의 관점에서 개선의 여지가 있다. 이에 본 논문에서는 업무프로세스를 보다 효율적으로 관리하는 새로운 방법을 제안한다. 제안한 방법은 업무참여자의 업무부하를 고려하여 전체 프로세스를 실행하는 방식으로서, 프로세스 참여자원 가운데 가장 큰 제약요소를 집중관리한다. 이러한 방식은 경영혁신이론으로 알려진 제약이론(Theory of Constraints)의 DBR (Drum-Buffer-Rope) 방법론을 기반으로 하고 있다. DBR 방법론을 활용하기 위해 우선, 업무프로세스와 DBR의 주적용모델의 차이점을 분석하고 업무프로세스에 적합한 드럼, 버퍼, 로프를 개발한다. 이를 토대로, 업무참여자의 업무부하와 프로세스 인스턴스 발생 패턴을 통제하는 BPM만의 DBR 방법론(BP-DBR, Business Process-DBR)을 제안한다. BP-DBR은 업무참여자의 업무환경과 전체프로세스의 효율성 개선에 기여할 것으로 기대한다. 이러한 기대효과를 증명하기 위해 기존 BPM의 프로세스 관리방법과 제안한 방법의 효과를 시뮬레이션 실험을 통해 비교한다.

• 한국지구과학회지
• /
• 제23권2호
• /
• pp.166-179
• /
• 2002

This study investigated preservice teachers' perceived constraints in implementing their ideal pedagogies and the influence of the teacher education program on their pedagogical beliefs changes. Unique features that the university-based coursework and field experiences had on preservice teachers' learning to teach were also explored. This preservice teacher education program employs constructivist aspects of teacher education and generates applications of constructivism to the practice of teaching. Major findings include: preservice teachers' having traditional pedagogy as the default, recovery of prior beliefs, constraints on implementing constructivist pedagogy, and being overly confident in themselves as teachers. With the influence of constructivist epistemology, these preservice teachers' pedagogical beliefs evolved and were refined over time as they incorporated various constructivist ideas. The benefits and influences of the M.Ed. program's theoretical coursework and the field experiences on these teachers' learning-to-teach experiences are addressed with rich data. The implications for teacher educators as well as for the instructional practices of preservice teacher education programs are discussed. Recommendations for future research are also presented.