• 제목/요약/키워드: Structured Uncertainty

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SWOT 분석을 통한 건설기업의 공기경쟁력 강화 전략 (Competitive Advantage Strategy of Construction Duration by SWOT Analysis)

  • 김선국;이현수;류한국
    • 한국건설관리학회논문집
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    • 제7권2호
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    • pp.109-117
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    • 2006
  • 건설산업의 경쟁은 신규 건설시장 축소, 최저가 입찰제도, 주 5일근무제도, 후분양제도의 도입 등에 따라 더욱 심화되고 있다. 이러한 건설환경의 급격한 변화는 산업의 주축을 이루고 있는 건설사들로 하여금 변화에 적응하고 더 나아가 새로운 환경을 선도하기 위한 다각적인 노력을 요구하고 있다. 그러나 건설공사는 공기지연을 유발하는 수많은 불확실성이 존재하고 있으며 이러한 불확실성에 대한 인식과 그에 따른 체계적인 전략수립과 관리가 부진한 경우 건설공사의 공기경쟁력을 확보하는 것은 매우 어렵다. 이에 본 연구는 적정 공사기간의 확보, 공기단축의 필요성, 기존의 공정전략 수립에 대한 연구가 부족함을 인식하고 건설사의 전반적인 전략 수립이 아닌 공기경쟁력 확보 측면에서 연구의 범위를 한정하였다. 본 연구는 건설산업의 대내외적 환경 분석과 SWOT 분석을 통하여 공기경쟁력 확보를 위한 전략을 수립하고 이를 이행하기 위한 선결과제를 도출하는 것을 목적으로 한다.

착공전 단계에서의 철근콘크리트 공사 공정리스크 관리 방안 (Schedule Risk Management of Reinforced Concrete Construction at the Preconstruction Phase)

  • 류한국;김선국;이현수
    • 한국건설관리학회논문집
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    • 제6권5호
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    • pp.119-127
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    • 2005
  • 최근의 건설시장 축소와 주 5일 근무제도, 공기단축형 입찰제도의 도입, 후분양제도의 도입 등의 제도적 변화에 따라 건설 수주 경쟁은 더욱 치열해지고 있다. 그러나 건설공사는 공기지 연을 유발하는 수많은 공정리스크가 존재하고 있으며 이러한 공정리스크에 대한 인식과 그에 따른 체계적인 관리가 부진한 경우 건설공사의 경쟁력을 확보하는 데 여러 어려움이 존재한다. 이러한 문제점을 해결하기 위한 기존 연구는 공정리스크의 분류, 공정 리스크의 관리, 리스크 관리를 위한 시스템 개발에 치중하였다. 이에 본 연구는 전체 공정에 영향력이 크며, 위험발생 확률이 높은 철근콘크리트공사를 대상공종으로 선정하고 기존연구를 바탕으로 수차례의 전문가 면담과 난상토론을 실시하여 현실적인 리스크 요인과 관리방안을 제시하였다.

The Experience of Miners Relocated to Alternative Positions due to Silicosis in the Andean of CODELCO, Chile, 2010

  • Delgado, Diemen;Aguilera, Maria De Los Angeles;Delgado, Fabian;Rug, Ani
    • Safety and Health at Work
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    • 제3권2호
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    • pp.140-145
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    • 2012
  • Objectives: To understand the personal experiences of mine workers that have experienced job relocation due to silicosis at the Andina Division of Corporaci$\acute{o}$n Nacional del Cobre (CODELCO), Chile. The purpose of the study was to provide useful information for the development of new local, business and public policies for the care of workers with silicosis. Methods: A qualitative study based on a practical case study of 5 workers. The information was collected by means of structured individual interviews. The method of analysis was phenomenology. Results: The corporal axis was the most commented upon. It included awareness of the illness, body pains, fatigue, and antagonistic mood disorders (sadness, or the difficulty in finding meaning in life). As far as personal relationships, there was evidence of strong relationships with family, coworkers and friends, as well as extended family. Over all, the experience of relocation was positive with periods of impatience and uncertainty. The job reassignment provided a new and pleasant context for the relocated workers and in the process improved their perception of their quality of life. Conclusions: A multidisciplinary team should attend mine workers relocated because of silicosis by addressing the mental and physical aspects of their disease, along with the integral participation of close family members. It is suggested that this investigation be maintain over time to record the personal experiences in the medium-term, adding new cases with the intention of shedding more light on the phenomenon being studied. As a preventive measure, continual workshops are needed on the proper use of respiratory protection in addition, a group of monitors is required.

파라미터 불확실성 시스템에 대한 견실 비약성 $H^\infty$ 제어기 설계 ((Robust Non-fragile $H^\infty$ Controller Design for Parameter Uncertain Systems))

  • 조상현;김기태;박홍배
    • 전자공학회논문지SC
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    • 제39권3호
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    • pp.183-190
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    • 2002
  • 본 논문에서는 구조화된 어파인(affine) 파라미터 불확실성을 가지는 시변 선형시스템과 구조적 불확실성을 가지는 상태궤환 제어기에 대한 견실 비약성 H∞ 제어기 설계방법을 다루었다. 또한 견실 비약성 H∞ 제어기가 존재할 충분조건, 제어기 설계방법 및 비약성을 만족하는 제어기의 꽉찬 집합(compact set)을 제시하였다. 이 때 제시한 조건은 변수치환과 슈어 여수(Schur complement)정리를 통하여 선형행렬부등식 (LMI : Linear Matrix Inequality)의 계수가 꽉찬 집합 내의 파라미터의 함수로 정의되는 파라미터화 선형 행렬부등식(PLMls: parameterized Linear Matrix Inequalities)으로 표현되므로 분리 볼록개념 (separated convexity concepts)에 기초한 완화기법을 이용하여 유한개의 LMI로 변환하였다. 그리고 본론문에서 제시한 견실 비약성 H∞ 제어기가 제어기이득의 변화에도 불구하고 폐루프시스템의 점근적 안정성 (asymptotic stability)과 외란감쇠 성능을 보장함을 보였다.

Challenges to Prevent in Practice for Effective Cost and Time Control of Construction Projects

  • Olawale, Yakubu A.
    • Journal of Construction Engineering and Project Management
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    • 제10권1호
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    • pp.16-32
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    • 2020
  • Cost and time control of projects is important in preventing project failure. However, achieving effective cost and time control in practice is often challenging. The challenges of project cost and time control in practice are investigated by carrying out a questionnaire survey on the top 150 construction contractors in the UK followed by in-depth semi-structured interviews of practitioners from 15 construction companies in the country. Quantitative analysis reveals that design change is the most important factor inhibiting the ability of UK contractors from effectively controlling both the cost and time of construction projects. Four of the top five factors inhibiting effective cost control are also the top factors inhibiting effective time control albeit in a different order. These top factors-design changes, inaccurate evaluation of project time/duration, risk and uncertainty, non-performance of subcontractors and nominated suppliers were also found to be endogenous factors to the project. Additionally, qualitative analysis of the interviews reveals 16 key challenges to prevent for effective project cost and time control in practice. These are classified into four categorised based on where they stem from as follows; from the organisation (1. Lack of integration of cost and time during project control, 2. lack of management buy-in, 3. complicated project control systems and processes, 4. lack of a project control training regime); from the construction management/project management approach (5. Lapses in integration of interfaces, 6. project control not being implemented from the early stages of a project, 7. inefficient utilisation and control of labour, 8. limited time devoted to planning how a project will be controlled at the outset); from the client; (9. Excessive authorisation gates, 10. use of adversarial and non-collaborative forms of contracts, 11. communication problems within client set-up, 12. obstructive client representatives) and; from the project team (13. Lack of detailed/complete design, 14. lack of trust among the project partners, 15. limited time devoted to project control on site, 16. non-factual reporting). The study posits that knowledge of these project control inhibiting factors and challenges is the first step at ensuring they are avoided and enable the implementation of a more effective project cost and time control process in practice.

Methodology for real-time adaptation of tunnels support using the observational method

  • Miranda, Tiago;Dias, Daniel;Pinheiro, Marisa;Eclaircy-Caudron, Stephanie
    • Geomechanics and Engineering
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    • 제8권2호
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    • pp.153-171
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    • 2015
  • The observational method in tunnel engineering allows the evaluation in real time of the actual conditions of the ground and to take measures if its behavior deviates considerably from predictions. However, it lacks a consistent and structured methodology to use the monitoring data to adapt the support system in real time. The definition of limit criteria above which adaptation is required are not defined and complex inverse analysis procedures (Rechea et al. 2008, Levasseur et al. 2010, Zentar et al. 2001, Lecampion et al. 2002, Finno and Calvello 2005, Goh 1999, Cui and Pan 2012, Deng et al. 2010, Mathew and Lehane 2013, Sharifzadeh et al. 2012, 2013) may be needed to consistently analyze the problem. In this paper a methodology for the real time adaptation of the support systems during tunneling is presented. In a first step limit criteria for displacements and stresses are proposed. The methodology uses graphics that are constructed during the project stage based on parametric calculations to assist in the process and when these graphics are not available, since it is not possible to predict every possible scenario, inverse analysis calculations are carried out. The methodology is applied to the "Bois de Peu" tunnel which is composed by two tubes with over 500 m long. High uncertainty levels existed concerning the heterogeneity of the soil and consequently in the geomechanical design parameters. The methodology was applied in four sections and the results focus on two of them. It is shown that the methodology has potential to be applied in real cases contributing for a consistent approach of a real time adaptation of the support system and highlight the importance of the existence of good quality and specific monitoring data to improve the inverse analysis procedure.

일부지역 임상치과위생사들의 치과위생사 의료인화에 대한 견해 (The opinions of some local clinical dental hygienists on medical personnel of dental hygienists)

  • 류혜겸
    • 한국치위생학회지
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    • 제18권6호
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    • pp.1067-1077
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    • 2018
  • Objectives: The purpose of the study is to investigate the opinions of some local clinical dental hygienists on medical personnel of dental hygienists. It will be for provide the Future dental hygienist basic data necessary for medical personnel. Methods: A self-reported questionnaire was completed by 171 dental hygienists in Busan and Gyeongnam from December 1, 2017 to January 31, 2018. Structured questionnaires were uesd for analysis. The questionnaire consisted of general characteristics of the subjects(7 items), medical personnel necessity and opinions of dental hygienist(2 items), the opinions of distinction of the task between dental hygienists and other personnel(2 items), many frequency task in the dental clinic. The collected data were analyzed using frequency, percentage, descriptive statistics and ANOVA using IBM SPSS VER 20.0. Results: 89.5% of the dental hygienists required medical personnel of dental hygienist, the opinions on the necessity were as follows: 'role and quality improvement as oral health professionals', 'lack of legislation and application of dental hygienists duties'. There was no difference reason between dental hygienists and other personnel on duties, the reason were investigated to uncertainty of dental hygienist system, lack of dental hygienist workforce, dentists lack awareness of dental hygienist expertise. There was surveyed by the current many frequency duties in the dental clinic, assist for dental treatment, Oral health education and counselling, Preventive dental treatment. Conclusions: Legal guarantees for clinical dental hygienists work are absolutely required. Therefore, relevant government agencies and related organizations should resolve the contradiction of the legal system of medical law and medical technicians. The clinical dental hygienists should be promoted to medical personnel through the amendment of the medical law so that the duties practiced by the dental hygienist can be matched with the legal practice.

Revisiting the Z-R Relationship Using Long-term Radar Reflectivity over the Entire South Korea Region in a Bayesian Perspective

  • Kim, Tae-Jeong;Kim, Jin-Guk;Kim, Ho Jun;Kwon, Hyun-Han
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2021년도 학술발표회
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    • pp.275-275
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    • 2021
  • A fixed Z-R relationship approach, such as the Marshall-Palmer relationship, for an entire year and for different seasons can be problematic in cases where the relationship varies spatially and temporally throughout a region. From this perspective, this study explores the use of long-term radar reflectivity for South Korea to obtain a nationwide calibrated Z-R relationship and the associated uncertainties within a Bayesian regression framework. This study also investigates seasonal differences in the Z-R relationship and their roles in reducing systematic error. Distinct differences in the Z-R parameters in space are identified, and more importantly, an inverse relationship between the parameters is clearly identified with distinct regimes based on the seasons. A spatially structured pattern in the parameters exists, particularly parameter α for the wet season and parameter β for the dry season. A pronounced region of high values during the wet and dry seasons may be partially associated with storm movements in that season. Finally, the radar rainfall estimates through the calibrated Z-R relationship are compared with the existing Z-R relationships for estimating stratiform rainfall and convective rainfall. Overall, the radar rainfall fields based on the proposed modeling procedure are similar to the observed rainfall fields, whereas the radar rainfall fields obtained from the existing Marshall-Palmer Z-R relationship show a systematic underestimation. The obtained Z-R relationships are validated by testing the predictions on unseen radar-gauge pairs in the year 2018, in the context of cross-validation. The cross-validation results are largely similar to those in the calibration process, suggesting that the derived Z-R relationships fit the radar-gauge pairs reasonably well.

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시맨틱 웹 기술혁신의 채택과 확산: 질적연구접근법 (The Adoption and Diffusion of Semantic Web Technology Innovation: Qualitative Research Approach)

  • 주재훈
    • Asia pacific journal of information systems
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    • 제19권1호
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    • pp.33-62
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    • 2009
  • Internet computing is a disruptive IT innovation. Semantic Web can be considered as an IT innovation because the Semantic Web technology possesses the potential to reduce information overload and enable semantic integration, using capabilities such as semantics and machine-processability. How should organizations adopt the Semantic Web? What factors affect the adoption and diffusion of Semantic Web innovation? Most studies on adoption and diffusion of innovation use empirical analysis as a quantitative research methodology in the post-implementation stage. There is criticism that the positivist requiring theoretical rigor can sacrifice relevance to practice. Rapid advances in technology require studies relevant to practice. In particular, it is realistically impossible to conduct quantitative approach for factors affecting adoption of the Semantic Web because the Semantic Web is in its infancy. However, in an early stage of introduction of the Semantic Web, it is necessary to give a model and some guidelines and for adoption and diffusion of the technology innovation to practitioners and researchers. Thus, the purpose of this study is to present a model of adoption and diffusion of the Semantic Web and to offer propositions as guidelines for successful adoption through a qualitative research method including multiple case studies and in-depth interviews. The researcher conducted interviews with 15 people based on face-to face and 2 interviews by telephone and e-mail to collect data to saturate the categories. Nine interviews including 2 telephone interviews were from nine user organizations adopting the technology innovation and the others were from three supply organizations. Semi-structured interviews were used to collect data. The interviews were recorded on digital voice recorder memory and subsequently transcribed verbatim. 196 pages of transcripts were obtained from about 12 hours interviews. Triangulation of evidence was achieved by examining each organization website and various documents, such as brochures and white papers. The researcher read the transcripts several times and underlined core words, phrases, or sentences. Then, data analysis used the procedure of open coding, in which the researcher forms initial categories of information about the phenomenon being studied by segmenting information. QSR NVivo version 8.0 was used to categorize sentences including similar concepts. 47 categories derived from interview data were grouped into 21 categories from which six factors were named. Five factors affecting adoption of the Semantic Web were identified. The first factor is demand pull including requirements for improving search and integration services of the existing systems and for creating new services. Second, environmental conduciveness, reference models, uncertainty, technology maturity, potential business value, government sponsorship programs, promising prospects for technology demand, complexity and trialability affect the adoption of the Semantic Web from the perspective of technology push. Third, absorptive capacity is an important role of the adoption. Fourth, suppler's competence includes communication with and training for users, and absorptive capacity of supply organization. Fifth, over-expectance which results in the gap between user's expectation level and perceived benefits has a negative impact on the adoption of the Semantic Web. Finally, the factor including critical mass of ontology, budget. visible effects is identified as a determinant affecting routinization and infusion. The researcher suggested a model of adoption and diffusion of the Semantic Web, representing relationships between six factors and adoption/diffusion as dependent variables. Six propositions are derived from the adoption/diffusion model to offer some guidelines to practitioners and a research model to further studies. Proposition 1 : Demand pull has an influence on the adoption of the Semantic Web. Proposition 1-1 : The stronger the degree of requirements for improving existing services, the more successfully the Semantic Web is adopted. Proposition 1-2 : The stronger the degree of requirements for new services, the more successfully the Semantic Web is adopted. Proposition 2 : Technology push has an influence on the adoption of the Semantic Web. Proposition 2-1 : From the perceptive of user organizations, the technology push forces such as environmental conduciveness, reference models, potential business value, and government sponsorship programs have a positive impact on the adoption of the Semantic Web while uncertainty and lower technology maturity have a negative impact on its adoption. Proposition 2-2 : From the perceptive of suppliers, the technology push forces such as environmental conduciveness, reference models, potential business value, government sponsorship programs, and promising prospects for technology demand have a positive impact on the adoption of the Semantic Web while uncertainty, lower technology maturity, complexity and lower trialability have a negative impact on its adoption. Proposition 3 : The absorptive capacities such as organizational formal support systems, officer's or manager's competency analyzing technology characteristics, their passion or willingness, and top management support are positively associated with successful adoption of the Semantic Web innovation from the perceptive of user organizations. Proposition 4 : Supplier's competence has a positive impact on the absorptive capacities of user organizations and technology push forces. Proposition 5 : The greater the gap of expectation between users and suppliers, the later the Semantic Web is adopted. Proposition 6 : The post-adoption activities such as budget allocation, reaching critical mass, and sharing ontology to offer sustainable services are positively associated with successful routinization and infusion of the Semantic Web innovation from the perceptive of user organizations.

스마트폰의 지각된 가치와 지속적 사용의도, 그리고 개인 혁신성의 조절효과 (An Empirical Study on Perceived Value and Continuous Intention to Use of Smart Phone, and the Moderating Effect of Personal Innovativeness)

  • 한준형;강성배;문태수
    • Asia pacific journal of information systems
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    • 제23권4호
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    • pp.53-84
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    • 2013
  • With rapid development of ICT (Information and Communications Technology), new services by the convergence of mobile network and application technology began to appear. Today, smart phone with new ICT convergence network capabilities is exceedingly popular and very useful as a new tool for the development of business opportunities. Previous studies based on Technology Acceptance Model (TAM) suggested critical factors, which should be considered for acquiring new customers and maintaining existing users in smart phone market. However, they had a limitation to focus on technology acceptance, not value based approach. Prior studies on customer's adoption of electronic utilities like smart phone product showed that the antecedents such as the perceived benefit and the perceived sacrifice could explain the causality between what is perceived and what is acquired over diverse contexts. So, this research conceptualizes perceived value as a trade-off between perceived benefit and perceived sacrifice, and we need to research the perceived value to grasp user's continuous intention to use of smart phone. The purpose of this study is to investigate the structured relationship between benefit (quality, usefulness, playfulness) and sacrifice (technicality, cost, security risk) of smart phone users, perceived value, and continuous intention to use. In addition, this study intends to analyze the differences between two subgroups of smart phone users by the degree of personal innovativeness. Personal innovativeness could help us to understand the moderating effect between how perceptions are formed and continuous intention to use smart phone. This study conducted survey through e-mail, direct mail, and interview with smart phone users. Empirical analysis based on 330 respondents was conducted in order to test the hypotheses. First, the result of hypotheses testing showed that perceived usefulness among three factors of perceived benefit has the highest positive impact on perceived value, and then followed by perceived playfulness and perceived quality. Second, the result of hypotheses testing showed that perceived cost among three factors of perceived sacrifice has significantly negative impact on perceived value, however, technicality and security risk have no significant impact on perceived value. Also, the result of hypotheses testing showed that perceived value has significant direct impact on continuous intention to use of smart phone. In this regard, marketing managers of smart phone company should pay more attention to improve task efficiency and performance of smart phone, including rate systems of smart phone. Additionally, to test the moderating effect of personal innovativeness, this research conducted multi-group analysis by the degree of personal innovativeness of smart phone users. In a group with high level of innovativeness, perceived usefulness has the highest positive influence on perceived value than other factors. Instead, the analysis for a group with low level of innovativeness showed that perceived playfulness was the highest positive factor to influence perceived value than others. This result of the group with high level of innovativeness explains that innovators and early adopters are able to cope with higher level of cost and risk, and they expect to develop more positive intentions toward higher performance through the use of an innovation. Also, hedonic behavior in the case of the group with low level of innovativeness aims to provide self-fulfilling value to the users, in contrast to utilitarian perspective, which aims to provide instrumental value to the users. However, with regard to perceived sacrifice, both groups in general showed negative impact on perceived value. Also, the group with high level of innovativeness had less overall negative impact on perceived value compared to the group with low level of innovativeness across all factors. In both group with high level of innovativeness and with low level of innovativeness, perceived cost has the highest negative influence on perceived value than other factors. Instead, the analysis for a group with high level of innovativeness showed that perceived technicality was the positive factor to influence perceived value than others. However, the analysis for a group with low level of innovativeness showed that perceived security risk was the second high negative factor to influence perceived value than others. Unlike previous studies, this study focuses on influencing factors on continuous intention to use of smart phone, rather than considering initial purchase and adoption of smart phone. First, perceived value, which was used to identify user's adoption behavior, has a mediating effect among perceived benefit, perceived sacrifice, and continuous intention to use smart phone. Second, perceived usefulness has the highest positive influence on perceived value, while perceived cost has significant negative influence on perceived value. Third, perceived value, like prior studies, has high level of positive influence on continuous intention to use smart phone. Fourth, in multi-group analysis by the degree of personal innovativeness of smart phone users, perceived usefulness, in a group with high level of innovativeness, has the highest positive influence on perceived value than other factors. Instead, perceived playfulness, in a group with low level of innovativeness, has the highest positive factor to influence perceived value than others. This result shows that early adopters intend to adopt smart phone as a tool to make their job useful, instead market followers intend to adopt smart phone as a tool to make their time enjoyable. In terms of marketing strategy for smart phone company, marketing managers should pay more attention to identify their customers' lifetime value by the phase of smart phone adoption, as well as to understand their behavior intention to accept the risk and uncertainty positively. The academic contribution of this study primarily is to employ the VAM (Value-based Adoption Model) as a conceptual foundation, compared to TAM (Technology Acceptance Model) used widely by previous studies. VAM is useful for understanding continuous intention to use smart phone in comparison with TAM as a new IT utility by individual adoption. Perceived value dominantly influences continuous intention to use smart phone. The results of this study justify our research model adoption on each antecedent of perceived value as a benefit and a sacrifice component. While TAM could be widely used in user acceptance of new technology, it has a limitation to explain the new IT adoption like smart phone, because of customer behavior intention to choose the value of the object. In terms of theoretical approach, this study provides theoretical contribution to the development, design, and marketing of smart phone. The practical contribution of this study is to suggest useful decision alternatives concerned to marketing strategy formulation for acquiring and retaining long-term customers related to smart phone business. Since potential customers are interested in both benefit and sacrifice when evaluating the value of smart phone, marketing managers in smart phone company has to put more effort into creating customer's value of low sacrifice and high benefit so that customers will continuously have higher adoption on smart phone. Especially, this study shows that innovators and early adopters with high level of innovativeness have higher adoption than market followers with low level of innovativeness, in terms of perceived usefulness and perceived cost. To formulate marketing strategy for smart phone diffusion, marketing managers have to pay more attention to identify not only their customers' benefit and sacrifice components but also their customers' lifetime value to adopt smart phone.