• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1196-1203
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• 2004

Autonomous agents need considerable computational resources to perform rational decision-making. The complexity of decision-making becomes prohibitive when large number of agents are present and when decisions have to be made under time pressure. One of approaches in time-critical domains is to respond to an observed condition with a predefined action. Although such a system may be able to react very quickly to environmental conditions, predefined plans are of less value if a situation changes and re-planning is needed. In this paper we investigate strategies intended to tame the computational burden by using off-line computation in conjunction with on-line reasoning. We use performance profiles computed off-line and the notion of urgency (i.e., the value of time) computed on-line to choose the amount of information to be included during on-line deliberation. This method can adjust to various levels of real-time demands, but incurs some overhead associated with iterative deepening. We test our framework with experiments in a simulated anti-air defense domain. The experiments show that the off-line performance profiles and the on-line computation of urgency are effective in time-critical situations.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.422-428
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• 1999

The mineral status of native goats and forage species, namely; Cynodon plectostachyus, Pennisetum purpureum. Eleusine indica, Cynodon dactylon, Calopogonium muconoides, Centrosema pubescens, Leucaena leococephala, and Mimosa pudica in lahar affected areas of Concepcion, Tarlac, Philippines were determined. Forage and blood samples were collected six times in 1996-97, and analyzed for calcium, phosphorus, magnesium, sulfur, copper, iron, molybdenum, selenium, and zinc. Forage calcium and sulfur are non-limiting. Most species had low phosphorus, copper and selenium, while some had magnesium and zinc levels lower than the critical limit because of low mineral content and high percolation rate of lahar deposits. Iron and molybdenum were in excess. The effect of seasonal variation was observed only in copper, sulfur and iron. Average blood mineral concentration of the animals was above critical limit, but there were no significant differences between seasons. All the animals had plasma phosphorus and magnesium above critical level; but 20 % had low copper, zinc and selenium especially in dry season possibly due to insufficient amount of these elements and excessive molybdenum and iron in most forage. Conversely, calcium in forage was high; but 40 % of the animals had low plasma calcium concentration. Although no clinical signs of mineral deficiencies were observed, supplemental feeding would be important since the condition of the pasture in lahar-laden areas is not expected to improve in the next five years. Intensified use of L. leucocephala with better mineral profile would be ideal.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.203-214
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• 2004

This paper presents a practical application of possibilistic programming in a information system projects planning model. The estimate of the parameters of the model is often a problematic task for the decision maker(DM), Who has imprecise information or express his considerations subjectively. In this case. possibilistic decision making models can provide an important aspect in handling practical decision making problems. We suggest CPM(Critical Path Method) applying possibilistic programming. CPM is an approach to planning and coordinating large projects by directing managerial focus to the project's most critical aspects and providing completion time of project and beginning time of each activity. This model is an aid in the control of considering aspiration levels by the DM, the fuzziness of decision making, and computational efficiency. The problem is solved by using GINO computer package and the best compromised solution is found.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.449-459
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• 2017

In Geum River of Korea, three multi-purpose weirs were built at the downstream of Daecheong Reservoir during the Four Major River Restoration Project (FMRRP). The weirs have altered the hydraulic characteristics of the river, and consequently transformed the large areas of flowing ecosystem to deep and wide stagnant environment. In every summer, a thermal stratification occurred near the Baekje Weir having mean depth of 4.0 m, and the surface algal blooms dominated by buoyant cyanobacteria have been frequently formed after the FMRRP. The objective of this study was to investigate the relationship between flow velocity and thermal stability of the waterbody using a three-dimensional (3D) hydrodynamic model (EFDC+) after calibration against the thermistor chain data obtained in 2014. A new Sigma-Zed vertical grid system of EFDC+ that minimize the pressure gradient errors was used to better simulate the thermodynamics of the waterbody. The model reasonably simulated the vertical profiles of the observed water temperatures. The vertical mean flow velocity and the Richardson Number (Ri) that represents the stability of waterbody were estimated for various management water levels and flow rates scenarios. The results indicated that the thermal stability of the waterbody is mostly high ($Ri{\gg}0.25$) enough to establish stratification, and largely depend on the flow velocity. The critical flow velocity that can avoid a persistent thermal stratification was found to be approximately 0.1 m/s.

• Nutrition Research and Practice
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• v.14 no.1
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• pp.12-19
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• 2020

BACKGROUND/OBJECTIVES: Vitamin D is a pleiotropic hormone that affects various body organ systems. We evaluated the prevalence of a vitamin D deficiency (VDD) and its potential role in the clinical condition of critically ill Korean children. SUBJECTS/METHODS: Patients under 18 years old with a 25(OH) vitamin D measurement on the first day of PICU admission were included from among the children admitted to the pediatric intensive care unit (PICU) of our tertiary children's hospital between October 2017 and January 2019. RESULTS: A total of 172 pediatric patients were enrolled. The mean 25(OH) vitamin D level was 17.5 ± 12.8 ng/mL. There was a 65.1% prevalence of VDD (25(OH) vitamin D level < 20 ng/mL). VDD was associated with age at PICU admission, gastrointestinal/hepatobiliary disorders, International Society of Thrombosis and Hemostasis disseminated intravascular coagulation (ISTH DIC) score, pediatric multiple organ dysfunction syndrome (pMODS) score and with several laboratory test findings including hemoglobin, platelet, C-reactive protein, serum albumin, total bilirubin, prothrombin time, and anti-thrombin III levels. Most of these parameters also showed significant linear correlations with the 25(OH) vitamin D level (P < 0.05). However, no statistically meaningful association was found between VDD and other clinical conditions such as the need for a mechanical ventilator, requirement for vasoactive drugs, duration of the PICU and hospital stays, or PICU mortality. CONCLUSION: There is a high prevalence of VDD in critically ill Korean children. There were significant associations between the 25(OH) vitamin D level and gastrointestinal/hepatobiliary disorders, the pMODS score and with coagulation related factors. Further large-scale studies with more specific subgroup analyses are required to more precisely assess the clinical implications of VDD in critically ill pediatric patients.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.201-209
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• 1998

The presence of elevated temperature can alter significantly the structural response of fibre-reinforced laminated composites. A thermal environment causes degradation in both strength and constitutive properties, particularly in the case of fibre-reinforced polymeric composites. Furthermore, associated thermal expansion, either alone or in combination with mechanically induced deformation, can result in buckling, large deflections, and excessively high stress levels. Consequently, it is often imperative to consider environmental effects in the analysis and design of laminated systems. Exact analytical solutions of higher-order shear deformation theory is developed to study the thermal buckling of cross-ply and antisymmetric angle-ply rectangular plates. The buckling behavior of moderately thick cross-ply and antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise is analyzed. Numerical results are presented for fiber-reinforced laminates and show the effects of ply orientation, number of layers, plate thickness, and aspects ratio on the critical buckling temperature and compared with those obtained using the classical and first-order shear deformation theory.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.1
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• pp.20-30
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• 2016

Objectives: To validate a critical-size mandibular bone defect model in miniature pigs. Materials and Methods: Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. Results: In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. Conclusion: The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2122-2129
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• 2002

Creep damage using a reference stress(RS) was analyzed for type 316LN stainless steel. The generalized K-R equation was reconstructed into the RS equation using a critical stress value $\sigma$. The RS equation was derived from the critical stress in failure time $t_f$ instead of material damage parameter $\omega$, which indicates the critical condition of collapse or approach to gross instability of materials during creep. For obtaining the reference stress, a series of creep tests and tensile tests were conducted with at 55$0^{\circ}C$ and $600^{\circ}C$. The stress-time data obtained from creep tests were applied to the RS equations to characterize the creep damage of type 316LN stainless steel. The value of creep constant r with stress levels was about 18 at 55$0^{\circ}C$ and 21 at $600^{\circ}C$. This value was almost similar with r = 24 in the K-R equation, which was obtained by using damage parameter $\omega$. Relationship plots of creep failure strain and life fraction $(t_f /t_r)$ were also obtained with different λ values. The RS equation was therefore more convenient than the generalized K-R equation, because the measuring process to quantify the damage parameter $\omega$ such as voids or micro cracks in crept materials was omitted. The RS method can be easily used by designers and plant operator as a creep design tool.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.223-230
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• 2019

The study aims to contribute to the improvement of project management in Vietnam. It focuses on developing new critical success factors (CSFs) which can be used to assess the success of project management in the country. This is a promising issue considering the rapid changes occurring within the business environment. The reason is because CSFs carry great consequences on project management issues, particularly in the context of Vietnam, which is currently experiencing many big scale projects involving both local and foreign investors. Two applications are utilised. One is to adapt the business model of Belassi and Tukel (1996) to observe the transitional and emerging economy of Vietnam. The other is to examine the data collected from a survey to examine the new CSFs which can then be used to assess the success of its projects and project management in Vietnam. The research results showed some remarkable differences between CSFs of Vietnam and foreign countries in both number of success factors and its impact levels which should be paid attention by foreign project managers/owners when doing investment and project management in Vietnam. The outcome generated can be useful to project owners/managers as well as policy makers in Vietnam's business environment.

• Progress in Superconductivity and Cryogenics
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• v.24 no.4
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• pp.40-45
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• 2022

The electrical/thermal stabilities and magnetic field controllability of a no-insulation (NI) high-temperature superconducting magnet are characterized by contact resistance between turn-to-turn layers, and the contact resistance characteristics are determined by properties of conductor surface and winding tension. In order to accurately predict the electromagnetic characteristics of the NI coil in a design stage, it is necessary to control the contact resistance characteristics within the design target parameters. In this paper, the contact resistance and critical current characteristics of a rare-earth barium copper oxide (REBCO) conductor were measured to analyze the effects of surface treatment conditions (roughness and oxidation level) of the copper stabilizer layer in REBCO conductor. The test samples with different surface roughness and oxidation levels were fabricated and conductor surface analysis was performed using scanning electron microscope, alpha step surface profiler and energy dispersive X-ray spectroscopy. Moreover, the contact resistance and critical current characteristics of the samples were measured using the four-terminal method in a liquid nitrogen impregnated cooling environment. Compared with as-received REBCO conductor sample, the contact resistance values of the REBCO conductors, which were post-treated by the scratch and oxidation of the surface of the copper stabilizer layer, tended to increase, and the critical current values were decreased under certain roughness and oxidation conditions.