• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.24-35
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• 2021

Due to increasing awareness on the treatment of end-of-use/life products, disassembly has been a fast-growing research area of interest for many researchers over recent decades. This paper introduces a novel lot-sizing problem that has not been studied in the literature, which is the service-parts lot-sizing with disassembly option. The disassembly option implies that the demands of service parts can be fulfilled by newly manufactured parts, but also by disassembled parts. The disassembled parts are the ones recovered after the disassembly of end-of-use/life products. The objective of the considered problem is to maximize the total profit, i.e., the revenue of selling the service parts minus the total cost of the fixed setup, production, disassembly, inventory holding, and disposal over a planning horizon. This paper proves that the single-period version of the considered problem is NP-hard and suggests a heuristic by combining a simulated annealing algorithm and a linear-programming relaxation. Computational experiment results show that the heuristic generates near-optimal solutions within reasonable computation time, which implies that the heuristic is a viable optimization tool for the service parts inventory management. In addition, sensitivity analyses indicate that deciding an appropriate price of disassembled parts and an appropriate collection amount of EOLs are very important for sustainable service parts systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.265-273
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• 2006

On the occasion of high price oil generation, we have to promote activation policy for public transportation and hold back to use passenger car, it is very important to improve of sidewalk environment for pedestrian. Evaluation for sidewalk environment will be fixed with sensibility to feel pedestrian. So, study for sensibility about comfort etc. to feel pedestrian will be carried out. In this paper, researchers interests in engineering methods to make material considering sensibility and image of human. Therefore, we carried out recognition experiment for sidewalk environment with Kansei engineering, and made a quantitativedata of sensibility adjective that it was surveyed by semantic deferential method. After grasp factors by principal analysis, we found factor effect to design criterion and sidewalk environment preference. So, we could identify a design factor for comfort environment.

• Health Policy and Management
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• v.33 no.3
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• pp.325-337
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• 2023

Background: While there are many studies estimating the effects of private health insurance on various types of health care utilization, few have examined how such effects change in conjunction with important policy reforms in national health insurance (NHI). This study examined how the effect of private health insurance (supplemental and fixed cash benefit) on high-cost outpatient imaging test utilization changed following the expansion of magnetic resonance imaging (MRI) coverage in 2018, which is a key example of the NHI benefit expansion policy in recent years. Methods: Data from the 2017 and 2019 Korea Health Panel Survey, which contained information about healthcare utilization before and after the expansion of MRI coverage in 2018, were used. The incremental effect of private health insurance on high-cost outpatient imaging test utilization for each period were quantified and compared, with special attention given to the type of private health insurance. Results: While people with supplemental private health insurance were more likely to use high-cost outpatient imaging tests than those without, both before and after the expansion of MRI coverage, the incremental effect increased from 1.6% points in 2017 to 2.5% points in 2019. Conclusion: Benefit expansion in NHI does not necessarily reduce disparities in the use of health care between private health insurance subscribers and non-subscribers. The results of our study also suggest that the path through which private health insurance affects healthcare utilization may not be limited to the price mechanism alone but can be more complex.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.157-158
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• 2023

Doors that are opened and closed when entering or exiting a general building are connected to the door frame and open and close. They are equipped with door locking devices of various structures, and are either locked to the door frame for the closing operation or released from the door frame for the opening and closing operation. Here, a single-stage door binding device having a door latch that is independently disposed at the center of one axis of the door is commonly used. On the other hand, if the size of the door is over a certain size or if the door is medium to large, the opening and closing operation may not be performed smoothly with only a single stage binder, or the closing state may not be achieved stably during the closing operation. In particular, in the case of the single-stage binding device provided in medium to large fire doors, the door is fixed to the door frame unstable, causing fatal errors in the fire prevention function of the fire door. Accordingly, in order to fundamentally solve these problems, we researched and developed a three-stage door binding machine that combines a top and bottom fastening structure with a single-stage fastening structure. This 3-stage door binder not only has the fire resistance performance of a fire door, but also has a T-shaped terminal in its fastening method, so if you eliminate the upper and lower fastening, it is a 1-stage binder like a regular product, but if you remove the door latch of the 1st-stage binder, it functions as an upper and lower 2-stage binder and forms a single mold. We researched and developed a three-stage door binder that can manufacture and produce three products at the same time, satisfying both product performance and price.

• Korean Journal of Construction Engineering and Management
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• v.25 no.2
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• pp.23-35
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• 2024

This study analyzed the correlation between each of the 12 influencing factors in FAR 16.04 and the decision-making process for construction contract types, using data from a total of 2,406 DoD Construction Acquisitions spanning from 2008 to 2022. The study considered 12 independent variables, grouped into 4 Characteristics with 3 factors each. Meanwhile, all other contract types were categorized into two types: Firm-Fixed-Price (FFP) and Cost-Reimbursement Contract (CRC), which served as the dependent variables. The findings revealed that FFP contracts significantly dominated in terms of acquisition volume. In line with prevailing beliefs, logistic data analysis and Analytical Hierarchy Process (AHP) analysis of Relative Weights from Experts' Survey demonstrated that independent variables like Uncertainty of the Scope of Work and Complexity found out to be increasing the likelihood of selecting CRC. The number of contractors in the market does indeed influence the possibilities of contract decision-making between CRC and FFP. Meanwhile, the p-values of the top 3 influencing factors on CRC from the AHP analysis-namely, Appropriateness of CAS, Project Urgency, and Cost Analysis-exceeded 0.05 in the binominal regression results, rendering it inconclusive whether they significantly influenced the construction contract type decision, particularly with respect to payment methods. This outcome partly results from the fact that a majority of respondents possessed specific experiences related to the USFK relocation project. Furthermore, influencing factors in construction projects behave differently than common beliefs suggest. As a result, it is imperative to consider the 12 influencing factors categorized into 4 Characteristics areas before establishing acquisition strategies for targeted construction projects.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.817-838
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• 2005

In this paper, the resource adequacy as well as the optimum fuel mix is obtained by the following procedures. First, the regulation body, the government agency, determine the reliability index as well as the optimum portfolio of the fuel mix during the planning horizon. Here, the resources with the characteristics of public goods such as demand-side management, renewable resources are assigned in advance. Also, the optimum portfolio is determined by reflecting the economics, environmental characteristics, public acceptance, regional supply and demand, etc. Second, the government announces the required amount of each fuel-type new resources during the planning horizon and the market participants bid to the government based on their own estimated fixed cost. Here, the government announces the winners of the each auction by plant type and the guaranteed fixed cost is determined by the marginal auction price by plant type. Third, the energy market is run and the surplus of each plant except their cost (guaranteed fixed cost and operating cost) is withdrew by the regulatory body. Here, to induce the generators to reduce their operating cost some incentives for each generator is given based on their performance. The performance is determined by the mechanism of the performance-based regulation (PBR). Here the free-riding performance should be subtracted to guarantee the transparent competition. Although the suggested mechanism looks like very regulated one, it provides two mechanism of the competition. That is, one is in the resource construction auction and the other is in the energy spot market. Also the advantages of the proposed method are it guarantee the proper resource adequacy as well as the desired fuel mix. However, this mechanism should be sustained during the transient period of the deregulation only. Therefore, generation resource planning procedure and market mechanisms are suggested to minimize possible stranded costs.

• Ecology and Resilient Infrastructure
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• v.7 no.2
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• pp.126-133
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• 2020

In accordance with the implementation of the sunset provision to cancel the designations of urban park sites that remained unexecuted for a prolonged period until 2020, the park sites in the city center, which account for 90% of the long-term unexecuted urban facilities subjected to the provision, are currently on the verge of development. The total area of the 204 park sites that will disappear in Seoul as a result of this provision is 95 ㎢; moreover, 116 of these are privately-owned. It is expected that the possible changes in the use of these park sites could result in reckless development and reduction of green space, which would ultimately affect the ecosystem. This study applied the InVEST model to calculate the changes in the fixed carbon amount before and after the implementation of the sunset provision to estimate the economic value of these changes. The study focused on Jongno-gu in Seoul because it has the most unexecuted park sites subjected to the lifting of the designation. The research findings show that the fixed carbon amount provided by the unexecuted park sites in Jongno-gu was 374,448 mg, prior to the implementation of the sunset provision; however, the amount was estimated to decrease by 18% to 305,564 mg after its execution. When calculated in terms of average value of the real carbon price, this translated into a loss of approximately 700 million won. In addition, considering the social costs including both climate change and the impact on the ecosystem, an economic loss of approximately 98 billion won was projected. This study is meaningful because its predictions are based on the estimation of fixed carbon amount according to the implementation of the sunset provision in Jongno-gu and scientifically calculates the value of ecological services provided by the parks in the city. This study can serve not only as a basis during the decision-making process for policies related to ecosystem conservation and development, but also as an evidentiary material for the compensation of privately-owned land that is designated as urban park sites and was unexecuted for a prolonged period.

• Journal of Korea Game Society
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• v.5 no.2
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• pp.19-27
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• 2005

The core price policy of on-line game marketing are FPP(Fixed Pre Paid model and PPU(Pay Per Use) model. These two models have been a on-line game company's billing system and a fundamental of MMORPG in Korea. However, they took root billing system only for first movers recently. In now, the market share of several first movers is exceeding 80%, late movers witch have same billing system cannot take part in pair competition. Even though in MMORPG, many games of late movers were favorably noticed by a lot of gamers during Evaluation. Test, a lot of companies are bankrupt before make business. Late Movers declare free game first thing, they maintain their existence and win over customers in on-line game market. And next, they guarantee item selling, give multiple experience value and game money, at last, induce their customers to pay service. As it makes trouble between pay user and free user, and it linked up with the collapse of game contents balance that designed for FPP billing system, And then meet unexpected result which reduction of game life cycle. In this Paper, we classified several contents services based on game contents, and suggested contents premium services which adopted low cost strategy lead to micro payment. we hope it will apply to late movers' new billing system in MMORPG.

• Journal of Distribution Science
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• v.14 no.5
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• pp.51-57
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• 2016

Purpose - In the year of 2015 and 2016, one of the items that got attention in CES was a drone. It has been 100 years since a drone emerged, but most were used for military purposes. As its use became diverse as of 2010, it got attention of the general public. In Korea, it was in 2011 that a drone was known to the public through an aerial video shooting for television program. This study tried to come up with suggestions by comparing domestic with overseas cases, and tried to consider the related technologies and systems with applying the role of drones in logistics service. Research design, data, and methodology - The overseas cases were regarded as drone's logistical purpose. The Prime Air service by US Amazon is still not commercialized and under pre-testing due to Federal Aviation Regulations, although it started in 2013. In Germany, DHL succeeded in delivering service testing which is called Parcelcopter, but it is not commercialized yet. Other than these, there are more attempts to prepare logistics service in China with Taobao, in France with Geopost's test, and in Africa. In Korea, CJ Korea Express tested delivery with a self-developed drone Results - In order to study for utilizing drones for logistics as the prerequisites, some overseas and domestic cases, which are currently considered, were reviewed. Also, the technologies and institutional requirements to commercialize drones for logistical purpose were reviewed. The reasons for using drones in logistics is to ensure the price competitiveness by reducing cost. The empirical test also will be needed because drone pilot areas are designated by ministry of land, infrastructure and transport. Conclusions - In order to utilize drones in logistics and foster the industry, this study would like to suggest the followings. First of all, size of drones for logistics needs to be fixed and their operating system should be standardized. Centralized investment resources are needed through standardization to ensure the market occupancy. Secondly, it is necessary to get the converged businesses that do research, develop and commercialize drones with the investment of private sector. Example can be found in Korea aerospace Industries. We can respond to the rapid growth of the market with intensive investing by integrating the private sector investment. Thirdly, institutional arrangements are needed to be established quickly. In the case of high-technologies like drones, institutional support often does not follow the rapid development of the technology. The problems can be found in securing drones-only airspace, creating drone-specialized pilot's license, matters related to remote controller and complementary regulations for drones in Aviation Act. If these regulations are not prepared or complemented at the right timing, technologies cannot be commercialized even though the development is completed. Fourthly, there is a need to secure the transparency regarding possible privacy and personal information protection problem while operating drones. Finally, in order to foster this new industry, government should focus on supporting R&D more in the long term than short term outcomes.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.5
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• pp.11-20
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• 1999

The data transfer width between the mocroprocessor and the memory comes to a critical part that limits system performance since the data transfer width has been as it was while the performance of a microprocessor is getting higher due to its continuous development in speed. And it is important that the memory should be in small size for the reduction of embedded microprocessor's price which is integrated on a single chip with the memory and IO circuit. In this paper, a mocroprocessor tentatively named as Extendable Instruction Set Computer(EISC) is proposed as the high code density 32 bit mocroprocessor architecture. The 32 bit EISC has 16 general purpose registers and 16 bit fixed length instruction which has the short length offset and small immediate operand. By using and extend register and extend flag, the offset and immediate operand could be extended. The proposed 32 bit EISC is implemented with an FPGA and all of its functions have been tested and verified at 1.8432MHz. And the cross assembler, the cross C/C++ compiler and the instruction simulator of the 32 bit EISC shows 140-220% and 120-140% higher code density than RISC and CISC respectively, which is much higher than any other traditional architectures. As a consequence, the EISC is suitable for the next generation computer architecture since it requires less data transfer width compared to any other ones. And its lower memory requirement will embedded microprocessor more useful.