• Journal of Digital Convergence
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• v.17 no.6
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• pp.355-363
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• 2019

This study is an analytical case study focusing on 'low-budget' mobile game development centered on both short-term development and small-scale collaboration. This study set up the assumption of four months as development period limited by three developers along with step by step productional documentation. In the previous study, we set up the responsibilities of the development personnels to analyze the effective process of the practical production. Furthermore, the study analyzed the usability verification of both advantages and disadvantages for conducting the quantitative survey with developer's feedbacks. The study is to provide the essential guideline for 'low-budget' development group with effective pipeline.

• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.101-108
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• 2019

Workflow management systems (WfMSs) automate and manage workflows, which are implementations of organizational processes operated in process-centric organizations. In this paper, wepropose an algorithm to discover temporal work transference networks from workflow execution logs. The temporal work transference network is a special type of enterprise social networks that consists of workflow performers, and relationships among them that are formed by work transferences between performers who are responsible in performing precedent and succeeding activities in a workflow process. In terms of analysis, the temporal work transference network is an analytical property that has significant value to be analyzed to discover organizational knowledge for human resource management and related decision-making steps for process-centric organizations. Also, the beginning point of implementinga human-centered workflow intelligence framework dealing with work transference networks is to develop an algorithm for discovering temporal work transference cases on workflow execution logs. To this end, we first formalize a concept of temporal work transference network, and next, we present a discovery algorithm which is for the construction of temporal work transference network from workflow execution logs. Then, as a verification of the proposed algorithm, we apply the algorithm to an XES-formatted log dataset that was released by the process mining research group and finally summarize the discovery result.

• Advances in materials Research
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• v.12 no.1
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• pp.15-29
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• 2023

In this paper, fracture analysis of a continuously inhomogeneous arch structure with two longitudinal cracks is developed in terms of the time-dependent strain energy release rate. The arch under consideration exhibits non-linear creep behavior. The cross-section of the arch is a rectangle. The material is continuously inhomogeneous along the thickness of the cross-section. The arch is loaded by two bending moments applied at its end sections. The mechanical behavior of the material is described by using a non-linear stress-strain-time relationship. The two longitudinal cracks are located symmetrically with respect to the mid-span of the arch. Due to the symmetry, only half of the arch is considered. Time-dependent solutions to strain energy release rate are obtained by analyzing the balance of the energy. For verification, time-dependent solutions to the strain energy release rate are derived also by considering the time-dependent complementary strain energy. The evolution of the strain energy release rate with the time is analyzed. The effects of material inhomogeneity, locations of the two cracks along the thickness of the arch and the magnitude of the external loading on the time-dependent strain energy release rate are evaluated.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.12 no.4
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• pp.240-251
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• 1983

The municipal government of Daejeon, Korea set up a plan to retrofit solar energy to the existing swimming pool. The pool was constructed in 1980, and meets the requirements of International standard. It will be used for the 1986 Asian Games and the 1988 Seoul Olymipics. The roof structure of the existing pool is to be modified to accomodate trickle solar collectors. In addition, various energy conserving ideas will be applied to the existing building structure. For the prevention of over heating of collectors on the roof, natural air convection scheme will be adopted within the collector system. Natural convection of passive type heating would be also adopted for the space heating of the pool when the system is idle. At present, the pool can be utilized only for two months a year without auxilairy heating. With oil heating, the energy cost would be too high for the normal operation. When this project completed in March 1984, it would be expected to be openable for seven months a year without a significan amount of auxiliary heating. In this project, two dimensional numerical analysis technic have been used to analyse the characterisitics of thermal performance of the swimming pool system. An experimental tat verification of the theoretical analysis have been also attempted.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.2
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• pp.90-100
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• 2021

Molten corium-concrete interaction (MCCI) is one of the most important phenomena that can lead to the potential hazard of late containment failure due to basemat penetration during a severe accident. In this study, MCCI analytical models of the CORQUENCH code were prepared through verification calculations of several experiments, which had been performed using concrete types similar to those of the calandria vault floor in CANDU-6 plants. The behaviors of thermal-hydraulic variables related to MCCI phenomena were analyzed under the conditions of dry floor and water flooding during the severe accident stemming from a hypothetic station blackout. Uncertainty analyses on the ablation depth were also carried out. It was estimated that the concrete ablation was not interrupted due to the continuous MCCI process under the dry condition but was terminated within 24 hours under the water flooding condition. It was confirmed that the water flooding as a mitigating action was effective to achieve the quenching and thermal stabilization of the melt discharged from the calandria vessel, showing that the present models are capable of reasonably simulating MCCI phenomena in CANDU-6 plants. This study is expected to provide the technical bases to the accident management strategy during the late-phase severe accidents.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3088-3101
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• 2023

A pressurized vessel-pipe-safety valve (PVPSV) combination is a commonly used configuration in nuclear power plants, and a good numerical model is essential for the system design, sizing and performance optimization. However, owing to the large-scale and cross-scale features, it is still a challenge to build a system level numerical model with both high accuracy and efficiency. To overcome this, a novel system level modeling method which can synthesize the advantages of various models is proposed in this paper. For system modeling, the analytical approach, the method of characteristics (MOC) and the surrogate model approach are respectively adopted to predict the dynamics of the pressure vessel, the connecting pipe and the safety valve, and different models are connected through data interfaces. With this system model, dynamic simulations were carried out and both the stable and the unstable system responses were obtained. For the model verification purpose, the simulation results were compared with those obtained from experiments and full CFD simulations. A good agreement and a better efficiency were obtained, verifying the ability of the model and the feasibility of the modeling method proposed in this paper.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4373-4391
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• 2022

Marine reactor systems experience platform movement, and therefore, the system thermal-hydraulic analysis code needs to reflect the motion effect on the fluid to evaluate reactor safety. A moving reactor model for MARS-KS was developed to simulate the hydrodynamic phenomena in the reactor under motion conditions; however, its applicability does not cover the MULTID component used in multidimensional flow analyses. In this study, a moving reactor model is implemented for the MULTID component to address the importance of multidimensional flow effects under dynamic motion. The concept of the volume connection is generalized to facilitate the handling of the junction of MULTID. Further, the accuracy in calculating the pressure head between volumes is enhanced to precisely evaluate the additional body force. Finally, the Coriolis force is modeled in the momentum equations in an acceleration form. The improvements are verified with conceptual problems; the modified model shows good agreement with the analytical solutions and the computational fluid dynamic (CFD) simulation results. Moreover, a simplified gravity-driven injection is simulated, and the model is validated against a ship flooding experiment. Throughout the verifications and validations, the model showed that the modification was well implemented to determine the capability of multidimensional flow analysis under ocean conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5A
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• pp.463-473
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• 2010

The purpose of this study was to investigate the performance of precast concrete copings for precast segmental PSC bridge columns. The proposed system can reduce work at a construction site and makes construction periods shorter. The precast concrete copings provides an alternative to current cast-in-place systems, particularly for areas where reduced construction time is desired. A model of precast concrete copings was tested under quasistatic monotonic loading. As a result, proposed precast coping system was equal to existing cast-in-place system in terms of required performance. In the companion paper, the experimental and analytical study for the performance assessment of precast concrete copings for precast segmental PSC bridge columns is performed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.346-355
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• 2006

The purpose of this study was conducted to ascertain the difference between impinger and passive sampling methods in the process of sampling and analyzing on airborne formaldehyde. Formaldehyde generating workplaces included in this study comprised four types of manufacturing industry such as two workplaces of products of wood, cork, straw and plaiting materials manufacturing industries, one casting metal manufacturing industry, and one parts and accessories for motor vehicles and it′s engines manufacturing industry. Workplaces contained in this study were located in some manufacturing area of Busan industrial complex and this study was carried out during a period from January 2003 to December 2004. Analytical accuracy, precision and detection limit of two methods was compared. Exposure level of its airborne concentration was evaluated in formaldehyde generating workplaces those were classified by types of industry, working process, and time. The results were as follows ; 1. A rate of recovery was 107.1% in impinger method and 101.8% in passive method, and precision was 7.79% in impinger method and 4.40% in passive method. There was no statistical significance in analytical accuracy and precision between two methods. A limitation of detection was 0.011 ppm in passive method which was lower than that of impinger method (0.020 ppm) by 1.8 times. 2. Airborne formaldehyde concentration of impinger method was different from passive method. It′s concentration by passive method was higher by 5.1 times than that by impinger method in the parts and accessories for motor vehicles and it′s engines manufacturing industry (P<0.05). Only in molding process among several types of processes, formaldehyde concentration in passive method was higher by 5.1 times than that in impinger method (P<0.05). Furthermore, formaldehyde concentration in passive method was higher by 1.7 times than that in impinger method (P<0.05) in the first half of year 2003. 3. The geometric mean of formaldehyde concentration in impinger method was lower than that in passive method, but there was no statistical significance of formaldehyde concentration by the difference of sampling method. In conclusion, it is difficult to conclude which is better between the two sampling methods because of no statistical significance for the difference of concentration. Because of lacks of certified passive sampling and analytical method, at present situation, studies on verification of accuracy and precision, obstructive reaction against validity on its exposure assessment, and research to develop domestically manufactured passive sampler in terms of cost-effectiveness should be continuously carried out.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.153-162
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• 2011

Composite box-girder with corrugated steel webs has been widely used in civil engineering practice as an alternative of conventional pre-stressed concrete box-girder because the efficiency of pre-stressing can be increased and weight reduction of superstructure can be achieved by replacing concrete webs as a corrugated steel webs. However, most of previous researches were limited in shear and flexural behavior of such girder so that the torsional behaviors of composite box-girder with corrugated steel webs are not fully understood yet and it needs to be investigated. Some of previous researchers developed the nonlinear theory for torsional analysis of composite box-girder with corrugated steel webs. However, their theories were developed by ignoring the tensile behavior of concrete. Thus, there are certain limitations in analysis of serviceability such as cracking moment and torsional stiffness of the girder. This paper presents the analytical model for torsional behavior of composite box-girder with corrugated steel webs considering tensile behavior of concrete. Based on the proposed analytical model, nonlinear torsional analysis program of composite box-girder with corrugated steel webs was developed. Then, for verification of validation of the developed model, test for the girder was conducted and the results were compared with those of analytical model. Finally, parametric study was conducted and the effects of tensile behavior of concrete on the torsional behavior of the girder were discussed.