• Proceedings of the Korea Society for Industrial Systems Conference
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• 2006.05a
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• pp.95-108
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• 2006

Because of rapid expansion of third party logistics, fierce competition in the transportation industry, and the diversification and globalization of transportation channels, an effective transportation planning by means of multimodal transport is badly needed. Accordingly, this study aims to suggest an optimal transport algorithm for the multimodal transport in the international logistics. Cargoes and stopovers can be changed numerously according to the change of transportation modes, thus being a NP-hard problem. As a solution for this problem, first of all, we have applied a pruning algorithm to simplify it, suggesting a heuristic algorithm for constrained shortest path problem to find out a feasible area with an effective time range and effective cost range, which has been applied to the Label Setting Algorithm, consequently leading to multiple Pareto optimal solutions. Also, in order to test the efficiency of the algorithm for constrained shortest path problem, this paper has applied it to the actual transportation path from Busan port of Korea to Rotterdam port of Netherlands.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.359-370
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• 2000

The purpose of this investigation was to observe the viscoelastic properties of five commercial flowable(Aeliteflo, Flow it, Revolution, Tetric flow, Compoglass flow), three conventional hybrid(Z-100, Z-250, P-60) and two condensable(Synergy compact, SureFil) resin composites. A dynamic oscillatory shear test was done to evaluate the storage shear modulus (G'), loss shear modulus(G"), loss tangent(tan ${\delta}$) and complex viscosity(${\eta}^*$) of the resin composites as a function of frequency - dynamic frequency sweep test from 0.01 to 100 rad/s at $25^{\circ}C$ - by using Advanced Rheometric Expansion System(ARES). To investigate the effect on the viscosity of resin composites of filler volume fraction, the filler weight % and volume % were measured by means of Archimedes' principle using a pyknometer. The results were as follows 1. The complex viscosity ${\eta}^*$ of flowable resins was lower than that of hybrid resins and significant differences were observed between brands. The complex viscosity ${\eta}^*$ of condensable resins was higher than that of hybrid resins. The order of complex viscosity ${\eta}^*$ at ${\omega}$=10 rad/s was as follows, Surefil, Synergy compact, P-60, Z-250, Z-100, Aeliteflo, Tetric flow, Compoglass flow, Flow it, Revolution. The relative complex viscosity of flowable resins compared to Z-100 was 0.04~0.56 but Surefil was 30.4 times higher than that of Z-100. 2. The storage shear modulus G' and the loss shear modulus G" of flowable resins were lower than those of hybrid resins but those of condensable resins were higher. The patterns of the change of loss tangent, tan ${\delta}$, of resin composites with increasing frequency were significantly different between brands. The phase angles, ${\delta}$, ranged from $30.2{\sim}78.1^{\circ}$ at ${\omega}$=10 rad/s. 3. All composite resins represent pseudoplastic nature with increasing shear rate. 4. The complex shear modulus $G^*$ and the phase angle ${\delta}$ was represented by the frequency domain phasor form, $G^*({\omega})=G^*e^{i{\delta}}=G^*{\angle}{\delta}$. The locus of frequency domain phasor plots in a complex plane was a valuable method that represent the viscoelastic properties of composite resins. 5. There was no direct linear correlationship but a weak positive relation was observed between filler volume % or weight % and the viscosity of the resin composites.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.2
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• pp.153-161
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• 2021

This study analyzed the ripple effect of the demand-side support for start-up venture companies on the macro economy using Dynamic General Equilibrium model. In the model, start-up venture companies were expressed in a manner that distinguished between workers and entrepreneurs by applying the span of control in the Lucas(1978). As a result of the analysis, when the share of public procurement of start-up venture companies was increased from 5.7% to 10%, the actual production of start-up venture companies increased by about 46.17% and the number of venture companies increased by about 150%. In addition, it was analyzed that the number of jobs through venture companies increased by about 61.56%. In addition, it was found that the economic effect was greatly reduced when the start-up venture company was supported as a subsidy for the supply sector with the same amount as the public procurement support. This is interpreted as the fact that if the government implements the supply-side support policy, the expansion of supply causes the price of start-up venture companies to fall, reducing the effect of the support policy in half. Therefore, when supporting start-up venture companies, the government should make efforts to maximize the policy effect by expanding the demand-side support through public procurement and reducing the payment of simple subsidies to start-up venture companies.

• Journal of Service Research and Studies
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• v.10 no.4
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• pp.101-125
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• 2020

This study was conducted to derive a management technology model based on the new management framework established in previous studies. The management technology sector, which occupies most of the existing business administration, is defined as a technical division in new management. In this study, the theory of management technology based on the service philosophy of the service economy era was presented. The structure of new business, which is the basis of new management technology, is presented first, the service philosophy of the service economy era where management is performed, and then the management technology model based on service philosophy is presented. The management technology model was derived on the basis of immutable axioms. After presenting new management axioms based on common human ideology and nature and human nature, a management technology model was presented based on axioms. On the basis of the axioms, a new dialectical development model was developed as a model for the dialectical development that maintains a tight balance and a fierce interaction between two opposing parties based on the structure and operation model of service philosophy. In addition to the overall organizational management model, a management function model and a management expansion model were presented. Each detailed technique is presented as a model for dialectical development of opposing confrontations. Management technology is a dynamic technology that is constantly changing, and is an overall technology that takes into account various situations and viewpoints. This study has significance as a basic study to overcome the limitations of the existing static management technology and develop dynamic management technology. Future research requires empirical analytical studies on new management technology models.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.52-62
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• 2008

As various types of embedded devices are widely used, a technology that supports reuse of applications on multiple platforms is needed in order for time-to-market development of the applications. The interface middleware is one of such technology and it hides platform dependency from application programmers. Existing interface middleware such as the MT project, Xenomai and Legacy2linux have limitation in that the APIs provided by each of these middleware are fixed to a specific operating system, and the middleware does not provide dynamic expansion of its API set. In this paper, we propose a middleware which hides operating system dependencies and enables porting of applications on various operating systems. In addition, the middleware has scalable structure so that it is suitable for resource-limited embedded systems. The overhead of the middleware, i.e., the time delay occurred by the middleware is between $0.3{\mu}sec\;and\;5{\mu}sec$ in most cases. We believe that the amount of overhead is reasonable and does not hurt the performance of applications.

• Korean Institute of Interior Design Journal
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• v.27 no.2
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• pp.45-54
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• 2018

Immersive space is a new type of space, which is converged with other domains and expressed in various ways and here, a mutual exchange between space and participants is realized with active intervention of participants. The purpose of this study is to examine boundary changes and characteristics in virtual space and reality or inside and outside, focusing on immersive space. For this study, a case analysis was conducted, based on the key words regarding flow experience and boundary characteristics in immersive space. The boundary characteristics extracted are as follow. First, while immersive space is overlapped in many different ways, the boundary in space gradually changes and one unique and convergent space is formed. Also, a combination of overlap is made with internal and external physical force and a convergent boundary is created. Second, forms are mixed in diverse ways and an unrealistic boundary space is revealed. For new experience, it has familiar, but new experiential characteristics and also shows an expanded boundary by the medium of different domains. Third, a simultaneous space, based on variability of time and space, has an ambiguous boundary due to a meaningless physical boundary of space and changing into a space region constantly, it becomes an unlimited variable space. Fourth, a linear expansion-based emergent space has nonlinearity, which creates a meaningless boundary, recognized as an irregular, dynamic and transformative space and expands to a creative space. In conclusion, it is anticipated that based on diverse characteristics found in immersive space, this study would give unlimited inspiration to many design fields and art creation activities and contribute to a further development through continued research on immersive space.

• Geomechanics and Engineering
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• v.13 no.1
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• pp.43-61
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• 2017

The inverted T-type abutments are generally used in highway bridges constructed in Korea. This type of abutment is used because it has greater stability, with more pile foundations embedded in the bedrock, while simultaneously providing support for lateral earth pressure and vertical loads of superstructures. However, the cross section of inverted T-type abutments is large compared with the piers, which makes them more expensive. In addition, a differential settlement between the abutment and embankment, as well as the expansion joints, causes driving discomfort. This study evaluated the driving comfort of several types of abutments to improve driving comfort on the abutment. To achieve this objective, a traditional T-type abutment and three types of candidate abutments, namely, mechanically stabilized earth wall (MSEW) abutment supported by a shallow foundation (called "true MSEW abutment"), MSEW abutment supported by piles (called "mixed MSEW abutment"), and pile bent and integral abutment with MSEW (called "MIP abutment"), were selected to consider their design and economic feasibility. Finite element analysis was performed using the design section of the candidate abutments. Subsequently, the settlements of each candidate abutment, approach slabs, and paved surfaces of the bridges were reviewed. Finally, the driving comfort on each candidate abutment was evaluated using a vehicle dynamic simulation. The true MSEW abutment demonstrated the most excellent driving comfort. However, this abutment can cause problems with respect to serviceability and maintenance due to excessive settlements. After our overall review, we determined that the mixed MSEW and the MIP abutments are the most appropriate abutment types to improve driving comfort by taking the highway conditions in Korea into consideration.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.2
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• pp.67-87
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• 1991

The computer program which predicts the gas exchange process of multi-cylinder 4-Stroke cycle spark-ignition engine, can be great assistance for the design and development of new engine. In this study, the computer program was developed to predict the gas exchange process of multi-cylinder four stroke cycle spark ignition engine including intake and exhaust systems. When gas exchange process is to be calculated, the evaluation of the variation of the thermo-dynamic properties with time and position in the intake and exhaust systems is required. For the purpose, the application of the generalized method of characteristics to the gas exchange process is known as one of the method. The simulation model developed was investigated to the analysis of the branch system of multi-cylinder. The models used were the 2-zone expansion model and single zone model for in cylinder calculation and the generalized method of characteristic including area change, friction, heat transfer and entropy gradients for pipe flow calculation. The empirical constants reduced to least number as possible were determined through the comparison with the experimented indicator diagram of one particular operation condition and these constants were applied to other operating condition. The predicted pressures in cylinder were compared with the experimental results over the wide range of equivalence ratio and ignition timing. The predicted values have shown good agreement with the experimental results. The thermodynamic properties in the intake and exhaust system were predicted over the wide range of equivalence ratio and ignition timing. The obtained results can be summarized as follows. 1. Pressures in the exhaust manifold have a little influence on the equivalence ratio, a great influence on the ignition timing. 2. Pressures in the inlet manifold are nearly unchanged by the equivalence ratio and the ignition timing. 3. In this study, the behaviors of the exhaust temperature, gas in the exhaust manifold were ascertained.

• Korea-Australia Rheology Journal
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• v.17 no.1
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• pp.21-25
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• 2005

Rheological properties and crystallization kinetics of the polypropylene (PP) block copolymer and recycled PP block copolymer were studied by advanced rheometric expansion system (ARES), differential scanning calorimetry (DSC), and optical microscopy. In the study of the dynamic rheology, it is observed that the storage modulus and loss modulus for the PP block copolymer and recycled PP block copolymer did not change with frequency. In the study of the effect of the repeated extrusion on the crystallization rate, half crystallization time of the PP samples was increased with the number of repeated extrusion in isothermal crystallization temperature ($T_c$). From the isothermal crystallization kinetics study, the crystallization rate was decreased with the increase of the number of repeated extrusion. Also, from the result of Avrami plot, the overall crystallization rate constant (K) was decreased with the increase of the number of the repeated extrusion. From the study of the optical microscopy, the size of the spherulite of the PP samples did not change significantly with the number of repeated extrusion. However, it was clearly observed that the number of the spherulite growth sites was decreased with the number of repeated extrusion. From the results of the crystallization rate, isothermal crystallization kinetics, Avrami plots, and optical microscopy, it is suggested that the crystallization rate of the PP block copolymer is decreased with the increase of the number of repeated extrusion.

• Korean Institute of Interior Design Journal
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• v.13 no.3
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• pp.84-92
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• 2004

This study concentrates on a new idea that is formulated as a creative spatialization in contemporary architecture and painting. It is stimulated from the classical baroque, which is expressed with the conceptual instruments, 'excessive', 'decorative', 'accidential' Suggested from that, this study tries to open the actual sense area of 'the baroque' by analysing the architectural ideas of wrenching and folding by Frank O. Gehry and in the same context by elucidating the dynamic deformalising of the figures by Francis Bacon. The redefined 'new baroque' operates in the chain of the transformable and flexible images that must be recognized as 'the real' in the sense of 'the most empirical' and are vulnerable to dispersal. The typical instrument of Gehry's 'new baroque architecture' is the enclosing of the space and its folding, and Bacon, whose painting can be called as the modern baroque, takes as the expressing methods a wrenching of the figures, a relieving of the colored background against the figure and a disappearing of figures into the background. These different ideas meet in the theoretical gravitation field of the philosophy of Deleuze, in which the reconstituted baroque conception means the tension between the folds, on expansion and contraction of which the variable space is dependent, Through the general principle of 'the new baroque', a free dispersal of power, to architect and painter is offered the possibility, not only to make the real world intimate to the real life, but also to produce from there a vivid new space. Finally it brings to enjoyer and viewer the possibility, to perceive the operating power in and around oneself.