• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.39-60
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• 1995

In this paper, an integration of stochastic dynamic programming (SDP), integer goal programming (IGP) and analytic hierarchy process (AHP) is proposed to handle multiobjective-multicriteria sequential decision making problems under uncertainty inherent in R & D investment planning. SDP has its capability to handle problems which are sequential and stochastic. In the SDP model, the probabilities of the funding levels in any time period are generated using a subjective model which employs functional relationships among interrelated parameters, scenarios of future budget availability and subjective inputs elicited from a group of decision makers. The SDP model primarily yields an optimal investment planning policy considering the possibility that actual funding received may be less than anticipated one and thus the projects being selected under the anticipated budget would be interrupted. IGP is used to handle the multiobjective issues such as tradoff between economic benefit and technology accumulation level. Other managerial concerns related to the determination of the optimal project portifolio within each stage of the SDP model. including project selection, project scheduling and annual budget allocation are also determined by the IGP. AHP is proposed for generating scenario-based transformation probabilities under budgetary uncertainty and for quantifying the environmental risk to be considered.

• Earthquakes and Structures
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• v.17 no.5
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• pp.463-475
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• 2019

In this paper, a procedure to develop fragility curves of structures equipped with semi-active tuned mass dampers (SATMDs) considering multiple failure criteria has been presented while accounting for the uncertainties of the input excitation, structure and control device parameters. In this procedure, Latin hypercube sampling (LHS) method has been employed to generate 30 random SATMD-structure systems and nonlinear incremental dynamic analysis (IDA) has been conducted under 20 earthquakes to determine the structural responses, where failure probabilities in each intensity level have been evaluated using Monte Carlo simulation (MCS) method. For numerical analysis, an eight-story nonlinear shear building frame with bilinear hysteresis material behavior has been used. Fragility curves for the structure equipped with optimal SATMDs have been developed considering single and multiple failure criteria for different performance levels and compared with that of uncontrolled structure as well as structure controlled using passive tuned mass damper (TMD). Numerical analysis has shown the capability of SATMDs in significant enhancement of the seismic fragility of the nonlinear structure. Also, considering multiple failure criteria has led to increasing the fragility of the structure. Moreover, it is observed that the influence of the uncertainty of input excitation with respect to the other uncertainties is considerable.

• Wind and Structures
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• v.11 no.1
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• pp.51-70
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• 2008

CFD is applied to evaluate pedestrian wind comfort at outdoor platforms in a high-rise apartment building. Model validation is focused on generic building sub-configurations that are obtained by decomposition of the actual complex building geometry. The comfort study is performed during the design stage, which allows structural design changes to be made for wind comfort improvement. Preliminary simulations are performed to determine the effect of different design modifications. A full wind comfort assessment study is conducted for the final design. Structural remedial measures for this building, aimed at reducing pressure short-circuiting, appear to be successful in bringing the discomfort probability estimates down to acceptable levels. Finally, the importance of one of the main sources of uncertainty in this type of wind comfort studies is illustrated. It is shown that the uncertainty about the terrain roughness classification can strongly influence the outcome of wind comfort studies and can lead to wrong decisions. This problem is present to the same extent in both wind tunnel and CFD wind comfort studies when applying the same particular procedure for terrain relation contributions as used in this paper.

• Journal of Korean Institute of Industrial Engineers
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• v.10 no.1
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• pp.27-36
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• 1984

This paper examines the influence of the uncertainty in demand and lead time on the relative performances of ten well-known single stage lot-sizing rules in a rolling schedule environment. Two other factors, coefficient of variation and time between orders, which may affect the performances of the rules are also considered. To compare the rules under an identical condition, 100% service level is set by introducing safety stocks. The effects of various factor levels are checked statistically by the pairwise t-test and the results show that the uncertainty of the environment has a strong influence on the performance of the rules.

• Ocean Systems Engineering
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• v.2 no.1
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• pp.1-16
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• 2012

Offshore wind turbines are complex structural and mechanical systems located in a highly demanding environment. This paper proposes a multi-level system approach for studying the structural behavior of the support structure of an offshore wind turbine. In accordance with this approach, a proper numerical modeling requires the adoption of a suitable technique in order to organize the qualitative and quantitative assessment in various sub-problems, which can be solved by means of sub-models at different levels of detail, both for the structural behavior and for the simulation of loads. Consequently, in a first place, the effects on the structural response induced by the uncertainty of the parameters used to describe the environmental actions and the finite element model of the structure are inquired. After that, a meso-level FEM model of the blade is adopted in order to obtain the detailed load stress on the blade/hub connection.

• Journal of Distribution Research
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• v.2 no.1
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• pp.115-141
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• 1997

This study examines the effects of economic and relational dimensions of supplier-distributor relationship on distributors intents to leave. A survey of 121 computer hardware distributors revealed that distributors commitment to the relationship and their transaction-specific investment would decrease directly the level of withdrawal intention. Other relational dimensions such as the procedural and distributive fairness, the morality of aspiration, and economic dimensions such as the transaction-specific investment made by the supplier and distributors expectations fo future performance increase indirectly the level of withdrawal intension via affecting either trust or commitment. The present study also found that perceived uncertainty and relative dependence might moderate the effects the economic and relational dimensions on distributors intents to leave. Relational dimensions, when compared to economic dimensions, tend to have stronger impacts on withdrawal intentions under high levels of uncertainty and relative dependence.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.49-55
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• 2005

Unconditional clearance levels were derived for fifteen short-lived radionuclides. Due to the uncertainty of long-term radiological impact analysis, alpha emitting nuclides and nuclides with half-lives longer than 30 years (except for C-14) were excluded from the scope of this study. The candidate waste streams are solid wastes and waste oil generated from nuclear power reactors. The clearance levels were derived by generic assessment for enveloping scenarios, along with specific assessment for each detailed scenario such as landfill, incineration and recycling. The derived values lie in the range from 0.01 to 100 Bq/g.

• Journal of Korea Technology Innovation Society
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• v.12 no.1
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• pp.212-236
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• 2009

This study is an attempt to deduct environmental uncertainties facing next-generation convergence services, in four areas including customer, technology, service provider and regulation. We assess the level of residual uncertainty with regard to key environmental uncertainty factors, and conduct a scenario planning analysis. Based on the results of this analysis, we provide suggestions on market entry strategy for providers of this next-generation convergence service. The strategic assessment of six scenarios developed in this study, each with two levels of residual uncertainty (alternate futures and a range of futures) resulted in two key success factors (KSF), namely, customer demand trends and easing of advertising restrictions. Four types of strategic scenarios were then discerned, for each of which we present response capabilities that may be required of service providers, along with strategic suggestions. The results of this study are rich in implications for both policy-makers and regulators seeking ways to create and stimulate a convergence service market and prospective providers of next-generation convergence services, as they provide concrete tips related to market entry strategy, including efficient resource allocation, types of market entry and time-frames for entry.

• The Journal of the Korea Contents Association
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• v.13 no.7
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• pp.168-180
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• 2013

Based on the strategic contingency theory, this study empirically examines Korean TV drama producers' changing adaptive behaviors in terms of genre variety given different levels of environmental uncertainty. The extant literature has suggested that firms tend to increase product variety in order to cope with increasing environmental uncertainty. This study attempted to verify the hypothesis that TV drama producers would employ wider variety of genre in the period with more uncertain environment(2003-2009) than the period with stable environment(1994-2002). Empirical results support the hypothesis, implying that TV drama producers tend to repeatedly produce dramas with the same genre in order to pursue efficiency in stable environment whereas they tend to employ a variety of different genre in order to cope with increasing environmental uncertainty.

• Journal of Korean Academy of Nursing
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• v.52 no.3
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• pp.308-323
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• 2022

Purpose: This study aimed to construct and test a predictive model for the quality of life (QOL) in mothers of children with developmental disabilities (DB). The hypothesized model included severity of illness, distress, uncertainty, self-help, and parenting efficacy as influencing factors, QOL as a consequence based on the Braden's Self-Help Model. Methods: The data were collected through a direct and online surveys from 206 mothers in 8 locations, including welfare or daycare centers, developmental treatment centers, and The Parents' Coalition for the Disabled located in two provinces of Korea. Data were analysed using SPSS/WIN 23.0 and AMOS 21.0 program. Results: The fit indices of the predictive model satisfied recommended levels; 𝛘² = 165.79 (p < .001), normed 𝛘² (𝛘²/df) = 2.44, RMR = .04, RMSEA = .08, GFI = .90, AGFI = .85, NFI = .91, TLI = .93, CFI = .95. Among the variables, distress (β = - .46, p < .001), parenting efficacy (β = .22, p < .001), and self-help (β = .17, p = .018) had direct effects on QOL. Severity of illness (β = - .61, p = .010) and uncertainty (β = - .08, p = .014) showed indirect effects. The explanatory power of variables was 61.0%. Conclusion: The study results confirm the utility of Braden's Self-Help Model. They provide a theoretical basis for improving QOL in mothers of children with DB. Nursing intervention strategies that can relieve mothers' distress and uncertainty related to disease and enhance parenting efficacy and self-help behavior should be considered.