• Journal of Astronomy and Space Sciences
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• v.19 no.1
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• pp.67-74
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• 2002

Optical observations of Geostationary and Molynia orbit spin-stabilized satellites over the Korean peninsula have been carried out at the Kyung Hee University Observatory with a 30 inch telescope. We have observed 5 spin-stabilized satellites, and obtained 0spin periods, which can be used for deducing a design for each bus model. Verifications of spin periods of 3 known satellites from manufacturer, and observations of 2 unknown satellites were made. The difference between known spin periods and observed spin periods is 0.06sec on the average and the difference of those spin rates is 3.3rpm on the average. Those results indicate that spin periods and spin rates of observed geostationary spin-stabilized satellites are within operating limits. Spin rates of unknown satellites, Fengyun 2B and Molynia 1-87 are 89.3rpm, 78.4rpm earh. It is suggested that the research of spin stabilized satellites can be used for the determinations of standard light sources for short period celestial objects and helpful for the constructions of satellite databases with photometric and/or spectroscopic satellite observations.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.212-218
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• 2003

State invariant is a property that holds in every reachable state. It can be used not only in understanding and analyzing complex software systems, but it can also be used for system verifications such as checking safety, liveness, and consistency. For these reasons, there are many vital researches for deriving state invariant from finite state machine models. In previous works every reachable state is to be considered to generate state invariant. Thus it is likely to be too complex for the user to understand. This paper seeks to answer the question `how to simplify state invariant\ulcorner`. Since the complexity of state invariant is strongly dependent upon the size of states to be considered, so the smaller the set of states to be considered is, the shorter the length of state invariant is. For doing so, we let the user focus on some interested scopes rather than a whole state space in a model. Computation Tree Logic(CTL) is used to specify scopes in which he/she is interested. Given a scope in CTL, mixed reachability analysis is used to find out a set of states inside it. Obviously, a set of states calculated in this way is a subset of every reachable state. Therefore, we give a weaker, but comprehensible, state invariant.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.6
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• pp.476-484
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• 2017

The purpose of this paper is to verify the structural integrity of a region with numerous penetration-holes in offshore structures such as semi-submersible rig and FPSO. In order to effectively check the yielding and buckling strength of plate members with penetration-holes, a screening analysis program was developed with the FE analysis tool to generate fine meshed model using the theoretical and analysis methods. When a hole is appeared in the plate structure members, the flow of stress is altered such that concentrations of stress form near the hole. Stress concentrations are of concern during both preliminary and detail design and need to be addressed from the perspectives of strength. To configure the geometrical shape, very fine meshed FE analysis is needed as the most accurate method. However, this method is practically impossible to apply for the strength verifications for all perforated plates. In this paper, screening analysis method was introduced to reduce analysis tasks prior to detailed FE analysis. This method is applied to not only the peak stress calculation combined stress concentration factor with nominal stress but also nominal equivalent stress calculation considering cutout effects. The areas investigated by very fine meshed analysis were to be chosen through screening analysis without any reinforcements for penetration-holes. If screening analysis results did not satisfy the acceptance criteria, direct FE analysis method as the 2nd step approach were applied with one of the coarse meshed model considering hole or with the very fine meshed model considering the hole shape and size. In order to effectively perform the local fine meshed analysis, automatic model generating program was developed based on the MSC/PATRAN which is pre-post FE analysis program. Buckling strength was also evaluated by Common Structure Rule (CSR) adopted by IACS as the stress obtained from very fine meshed FE analysis. Due to development of the screening analysis program and automatic FE modeling program, it was able to reduce the design periods and structural analysis costs.

• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.911-920
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• 2010

The closed water bodies, such as reservoirs and lakes, could be contaminated by an inflow of pollutants in the upstream as well as a stratification caused by seasonal natural phenomena. The vertical circulation particularly plays an important role in reduction of environmental pollutants. The factors of the vertical circulation are the temperature, wind, thermal diffusivity and sunlight. The wind is probably the most significant factor among them. Thus, it is necessary to describe the validation and application of a three-dimensional numerical model of wind-induced circulation in a thermally stratified flow. In this paper, a three-dimensional numerical model for the thermally stratified flows is presented. The model is conducted in three steps to calculate the velocity components from the momentum equations in x- and y- axis directions, the elevations from the free surface equation and the temperature from the scalar transport equation. Numerical predictions are compared with available analytical solutions for the sloshing free surface movement in a rectangular basin. The numerical results generally show a reasonable agreement with analytical solutions. And the model is applied to the circulation for the wind induced flow in a thermally stratification. Consequently, the developed model is validated by two verifications and phenomena of the internal flow.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.891-901
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• 2016

By comparing test blasting data experimented in three layered-structure polymorphic grounds to a geological profile, influence of blast vibration with respect to uncontrollable ground characteristics was analyzed. Inefficient blast have been performed without sufficient verifications or confirmations because insufficiencies with regard to experiments and data of blasting engineering on the layered structures to be irregularly repeated clinker layer consisted of volcanic clastic zones. It is difficult to quantify N values of clinkers within test blasting region because they have diverse ranges, or coverages. An absolute value of attenuation coefficient N in a field, estimated by blasting vibration predictive equation (SRSD), are lesser than criteria of a design instruction, meaning that vibrations caused by blast can spread far away, and the vibrational characteristics of blasting test No.1, indicating relatively small values, inferred by the geological profile, pressures of gas by the explosion may be lost into a widely distributed clinker layers by penetrating holes resulted from blast into vicinity of clinker layers located in bottom of soft rock layers at the moment of blast. As a result, amounts of spalling rocks are decreased by almost half. Also, ranges of primary frequencies in the fields are identified as similar to those of natural frequency of typical structures.

• Journal of Global Scholars of Marketing Science
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• v.17 no.4
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• pp.201-221
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• 2007

Recently price as an information clue on online shopping has become important and price dependency has been also increased. This study suggests the flow which customers experience on online shopping plays a leading role in a matter of revisiting intention, but price sensitivity has a possibility to decrease the flow on the basis of literature investigation. While telling the differences in types of shopping malls, this study also examines relationship verifications with price sensitivity, flow of internet shopping mall and revisiting intension. The results show the flow experience through temporal dissociation makes increase a revisiting intention. To the contrary, this study presents a price search dimension in price sensitivity has negative influence to each dimension of temporal dissociation, heightened enjoyment and curiosity and also the relationship between price importance and flow is rejected. In addition, this influence gets different results by internet auction, pure internet shopping mall, shopping mall which can show price comparisons. In the case of shopping mall which can show price comparisons, more price researches become less curiosities and more heightened enjoyments and curiosities get more revisiting intentions. In the internet auction's case, price search decreases a temporal dissociation and heightened enjoyment and improves a revisiting intention when a temporal dissociation and heightened enjoyment are increased. Price research reduces three types of flow dimensions such as a temporal dissociation, heightened enjoyment, and curiosity in the pure internet shopping mall. In addition, only heightened enjoyment affects to a revisiting intentions.

• Management & Information Systems Review
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• v.35 no.3
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• pp.131-153
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• 2016

This research suggests a structural model of green purchase behavior, focusing on the moderating effect of affordability. Affordability means buying power or ability to buy products. Based on the literature review, a research model of behavior of buying green products was proposed and tested empirically using the field study. To examine the proposed research model, the reliability and validity verifications on measurement items were carried out and then the structural equation model analysis was applied to test the model. Lastly, to test the moderating effect of affordability, a two-group model(using Amos program) was used subsequently so that it could be determined whether or not there was any significant difference in structural parameters between the high affordability group and the low affordability group. The empirical results are as follow: Firstly, green purchase attitude is influenced by ecological concern and collectivism, then green purchase attitude has an impact on green purchase intention, and in turn, green purchase intention affects green purchase behavior. Secondly, affordability significantly moderates the relationship between green purchase intention and green purchase behavior. These results are consistent with the past researches and based on them, some managerial implications are given.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2484-2496
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• 2000

High speed switches have been developing to interconnect a large number of nodes. It is important to analyze the switch performance under various conditions to satisfy the requirements. Queueing analysis, in general, has the intrinsic problem of large state space dimension and complex computation. In fact, The petri net is a graphical and mathematical model. It is suitable for various applications, in particular, manufacturing systems. It can deal with parallelism, concurrence, deadlock avoidance, and asynchronism. Currently it has been applied to the performance of computer networks and protocol verifications. This paper presents a framework for modeling and analyzing ATM switch using stochastic activity networks (SANs). In this paper, we provide the ATM switch model using SANs to extend easily and an approximate analysis method to apply A TM switch models, which significantly reduce the complexity of the model solution. Cell arrival process in output-buffered Queueing A TM switch with finite buffer is modeled as Markov Modulated Poisson Process (MMPP), which is able to accurately represent real traffic and capture the characteristics of bursty traffic. We analyze the performance of the switch in terms of cell-loss ratio (CLR), mean Queue length and mean delay time. We show that the SAN model is very useful in A TM switch model in that the gates have the capability of implementing of scheduling algorithm.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.2 no.4
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• pp.43-68
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• 2007

The purpose of this paper is to clarify the actual conditions of entrepreneurial school which was drawn from the new industry-academy cooperation paradigm, and to suggest a role model for educational program for entrepreneurial school, in order to increase its self-generating ability. According to survey of 5 entrepreneurial schools, most of curriculums did not show a user-based. This indicates that series of processes, such as analyzing user's(learner, local community, institution) request and setting up the goal are not being conducted professionally and systematically. Through this study, I would like to deliver the importance of new industry-academy cooperation paradigm of entrepreneurial schools and incite them to apply major principles of new industry-academy cooperation paradigm to their entrepreneurial education program, in order to enable continuous survival and development. This study has conducted research on the actual conditions of entrepreneurial school to examine whether the role model of entrepreneurial education program coincides with the paradigm of new industry-academy cooperation paradigm. Thus, this study has conducted two verifications as whole. First, through theoretical examination, this study has drawn out the major principles of new industry-academy cooperation paradigm and considered effective applying method for it. Second, this study has analyzed overseas' cases for development of entrepreneurial education program and proved the propriety of major principles. Through theory and case studies, the study presented a role models for each subjects and provided necessity for applying major principles to entrepreneurial school's research on the actual operating condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.1
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• pp.31-37
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• 2016

Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.