• Environmental and Resource Economics Review
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• v.26 no.3
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• pp.417-449
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• 2017

The purpose of this study is to analyze the effect of local area concentration of particulate matter on life satisfaction, by matching subjective satisfaction in the Korea Labor & Income Panel Study data with daily data of $PM_{10}$ and $PM_{2.5}$. We find that the concentration of particulate matter has a significant negative effect on satisfaction. A $1{\mu}g/m^3$ increase in $PM_{10}$($PM_{2.5}$) leads to lower the probability of choosing 'satisfaction' by 0.042%p~0.091%p(0.034%p~0.153%p) and a 1% increase in annual income per household raises the probability of choosing 'satisfaction' by 0.16%p~0.18%p respectively. To estimate the monetary value of reducing $PM_{10}$ and $PM_{2.5}$, we calculate willingness-to-pay for mitigating air pollution, which represents the tradeoff between the reduction in particulate matter and income. We find that people on average are willing to pay \108,787($96)~209,519($186) for a $1{\mu}g/m^3$ reduction in $PM_{10}$ and to pay 89,345($79)~362,930($322) in $PM_{2.5}$. This amount corresponds to 0.26%~0.50%(0.22%~0.88%) of the average annual household income in South Korea.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.259-271
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• 2013

This paper addresses the efficient facility placements to adopt a super WiFi network, taking significant considerations as the next generation 'information highway'. Since the super WiFi has a wider geographic coverage by utilizing the white spaces of TV broadcasting which are empty and available frequencies for the wireless communications, it would play an important role in releasing digital divide of the internet access for low populated or mountainous areas. The purpose of this paper is to explore systematic and efficient spatial plans for the super WiFi. For doing this, we applied optimal location covering models to Gurye-gun, Jeonlanamdo. From the application, we presented optimal locations for super WiFi facilities and significant analytical results, such as the tradeoff between the number of facilities and coverage and marginal coverage for establishing super WiFi network. The results of this research would be usefully utilized for decision makers who wish to adopt a super WiFi, to extend wireless networks in a city or build a regional infrastructure of wireless facilities.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.1-10
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• 2001

In this paper, a multistage parallel interference canceller (MPIC) and a partial multistage parallel interference canceller (PMPIC) are employed as a technique for improving the performance of the asynchronous DS-CDMA systems. The degree of the effect of the timing errors and phase errors on the interference cancellation capability of two types of cancellers is theoretically analyzed and the computer simulation is performed to confirm the analytical results. From the results, the large performance improvement is obtained by employing MPIC and PMPIC with perfect synchronization over the conventional matched filter, and the performance improvement obtained by MPIC and PMPIC is very close to each other as the number of the stage of MPIC and PMPIC increases. When the timing errors and phase errors are considered (in the case of imperfect synchronization), the performance improvement reduces as the performance degradation at the first stage (no cancellation) has a bad effect on the decision statistics at each stage. However MPIC and PMPIC have the strong interference cancellation capability in spite of imperfect synchronization as the number of the stage increases. An interference canceller, which has the strong interference cancellation capability as well as lower complexity for the implementation, is needed for practical systems with timing errors and phase errors because the perfect synchronization is impossible. Therefore, the excellent tradeoff between complexity and performance offered by PMPIC makes it an attractive approach for practical systems.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.417-424
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• 2007

Mesh networks using WLAN technology have been paid attention as a key wireless access technology. However, many technical issues still exist for its successful deployment. One of those issues is the routing problem that addresses the path setup through a WLAN mesh network for the data exchanges between a station and a wired network. Since the characteristics of a WLAN mesh network can be very dynamic, the use of single routing protocol would not fit for all environments whether it is reactive or proactive. Therefore, it is required to develop an adaptive routing protocol that modifies itself according to the changes in the network parameters. As a logical first step for the development, an analytical model considering all the dynamic features of a WLAN mesh network is required to evaluate the performance of a reactive and a proactive routing scheme. In this paper, we propose an analytical model that makes us scrutinize the impact of the network and station parameters on the performance of each routing protocol. Our model includes the size of a mesh network, the density of stations, mobility of stations. and the duration of network topology change. We applied our model to the AODV that is a representative reactive routing protocol and DSDV that is a representative proactive routing protocol to analyze the tradeoff between AODV and DSDV in dynamic network environments. Our model is expected to help developing an adaptive routing protocol for a WLAN mesh network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2083-2090
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• 2006

In an proposed Context-Aware SOA(Service Oriented Architecture) based OSGi(Open Service Gateway initiative) platform, Service provider manages relative kinds of services in an integrative basis from various sensors, puts each service in a SOAP (Simple Object access Protocol) message, and register thorn to the UDDI(Universal Description Discovery and Integration) server of service registry, service requester retrivel the specified kinds of services and call them to service provider. Recently most context-aware technologies for ubiquitous home network are mainly putting emphasis on RFID/USN and location-based technology. Because of this, service-oriented architecture researches have not been made enough. Under the environment of an OSGi service platform, various context-aware services are dynamically mapping from various sensors, new services are being offered for the asking of users, and existing services are changing. Accordingly, the data sharing between services provided, management of service life cycle, and the facilitation of service distribution are needed. Taking into considering all these factors, this study has suggested an Context-Aware SOA based eclipse SOA Tools Platform using OSGi platform that can transaction throughtput of more than 546 TPS of distributional Little's Law from ATAM(Architecture Tradeoff Analysis Method) while remaining stable other condition.

• The Journal of Society for e-Business Studies
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• v.24 no.3
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• pp.19-33
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• 2019

Recently, manufacturers have been struggling to efficiently use production equipment as their production methods become more sophisticated and complex. Typical factors hindering the efficiency of the manufacturing process include setup cost due to job change. Especially, in the process of using expensive production equipment such as semiconductor / LCD process, efficient use of equipment is very important. Balancing the tradeoff between meeting the deadline and minimizing setup cost incurred by changes of work type is crucial planning task. In this study, we developed a scheduling model to achieve the goal of minimizing the duedate and setup costs by using reinforcement learning in parallel machines with duedate and work preparation costs. The proposed model is a Deep Q-Network (DQN) scheduling model and is a reinforcement learning-based model. To validate the effectiveness of our proposed model, we compared it against the heuristic model and DNN(deep neural network) based model. It was confirmed that our proposed DQN method causes less due date violation and setup costs than the benchmark methods.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.15-15
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• 2021

Seed coat color and seed weight are among the key agronomical traits that determine the nutritional quality of soybean seeds. This study aimed to evaluate the contents of total protein, total oil and five prominent fatty acids in seeds of 49 soybean varieties recently cultivated in Korea, and assess the influences of seed coat color and seed weight on each. Total protein and total oil contents were in the ranges of 36.28-44.19% and 13.45-19.20%, respectively. Likewise, individual fatty acid contents were in the ranges of 9.90-12.55, 2.45-4.00, 14.97-38.74, 43.22-60.26, and 5.37-12.33% for palmitic, stearic, oleic, linoleic, and linolenic acids, respectively. Our results found significant variations of protein, oil and fatty acid contents between the soybean varieties. Moreover, both seed coat color and seed weight significantly affected total oil and fatty acid contents. Total protein content, however, was not significantly affected by any factor. Among colored soybeans, pale-yellow soybeans were characterized by a high level of oleic acid (30.70%) and low levels of stearic (2.72%), linoleic (49.30%) and linolenic (6.44%) acids, each being significantly different from the rest of colored soybeans (p < 0.05). On the other hand, small soybeans were characterized by high levels of all individual fatty acids except oleic acid. The level of oleic acid was significantly high in large seeds. Cluster analysis grouped the soybeans into two classes with notable content differences. Principal component analysis also revealed fatty acids as the prime factors for the variability observed among the soybean varieties. As expected, total oil and total protein contents showed a negative association with each other (r = -0.714, p < 0.0001). Besides, oleic acid and linoleic acid showed a tradeoff relationship (r = -0.936, p < 0.0001) which was reflected with respect to both seed coat color and seed weight. In general, the results of this study shade light on the significance of seed coat color and seed weight to distinguish soybeans in terms of protein, oil and fatty acid contents. Moreover, the soybean varieties with distinct characteristics and nutritional contents identified in this study could be important genetic resources for consumption and cultivar development.

• Information Systems Review
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• v.20 no.1
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• pp.137-158
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• 2018

Online platforms recently expanded their connectivity through an authing service. The growth of authing services enabled consumers to enjoy easy log in access without exerting extra effort. However, multiple points of access increases the security vulnerability of platform ecosystems. Despite the importance of balancing authing service and security, only a few studies examined platform connectivity. This study examines the optimal level of authing service of a platform and how authing strategies impact participants in a platform ecosystem. We used a game-theoretic approach to analyze security problems associated with authing services provided by online platforms for consumers and other linked platforms. The main findings are as follows: 1) the decreased expected loss of consumers will increase the number of players who participate in the platform; 2) linked platforms offer strong benefits from consumers involved in an authing service; 3) the main platform will increase its effort level, which includes security cost and checking of linked platform's security if the expected loss of the consumers is low. Our study contributes to the literature on the relationship between technology convenience and security risk and provides guidelines on authing strategies to platform managers.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.475-488
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• 2018

This study evaluates geothermal system efficiency in terms of input power and heat exchange volume on the heat-source and load sides, by applying a combined open-closed type loop system comprising a geothermal system and a groundwater well to a cultivation site. In addition, this study analyzes the effects of heating and cooling for a complex geothermal system, by evaluating the temperatures of an external site and a cultivation site during operation. During cooling operations the heat exchange volume on the heat source side, average 90.0kW/h for an open type system with an input of 235L/minute groundwater, and 40.1kW/h for a closed type system with an input of 85L/minute circulating water, for a total average heat exchange volume of 130.1kW/h. The actual heat exchange volume delivered on the load side averages 110.4kW/h. The average EER by analysis of the geothermal system's cooling efficiency is 5.63. During heating operation analysis, the heat exchange volume on the heat source side, average 60.4kW/h in an open type system with an input of 266L/minute groundwater, and 22.4kW/h in closed type system with an input of 86L/minute circulating water, for a total average heat exchange volume of 82.9kW/h. The actual heat exchange volume delivered on the load side averages 112.0kW/h in our analysis. The average COP determined by analysis of the geothermal system's heating efficiency is 3.92. Aa a result of the tradeoff between the outside temperature and the inside temperature of the production facility and comparing the facility design with a combined well and open-closed loops geothermal(CWG) system, we determine that the 30RT-volume CWG system temperature are lower by $3.4^{\circ}C$, $6.8^{\circ}C$, $10.1^{\circ}C$ and $13.4^{\circ}C$ for ouside temperature is of $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$, respectively. Based on these results, a summer cooling effect of about $10^{\circ}C$ is expected relative to a facility without a CWG system as the outside temperature is generally ${\geq}30^{\circ}C$. Our results suggest that a complex geothermal system provides improvement under a variety of conditions even when heating conditions in winter are considered. Thus It is expected that the heating-cooling tradeoffs of complex geothermal system are improved by using water screen.

• Journal of the Korean Professional Engineers Association
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• v.28 no.4
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• pp.54-75
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• 1995

This synthesis has been prepared from a review of literature on Truck Escape Ramps technology and a survey of current practice by state department of transportation. Their locations have been determined usually from a combination of accident experience and en-gineering judgement, but new tools are emerging that can identify needs and sites without waiting for catastrophic accidents to happen. The Grade Severity Rating Systems holds promise in this regard. Design Procedures for truck excape ramps continue to evolve. Gravel arrester beds are clearly the preferred choice across the country Rounded aggregate, uniformly graded in the approximate size range of 13 to 18mm. Tech-nical publications typically have dassified TER types as paved gravity, sandpile, and ar-rester bed ramps. The design speed for vehicle entry into the ramp in critical to the deter-mination of ramp length. An escape ramp should be designed for a minimum entry speed of 130km/hr, a 145km/hr design being preferred. The ramps should be straight and their angle to the roadway align-ment should be as possible. The grade of truck escape ramps show the adjustment of ramp design to local topography, such as the tradeoff of ramp length against earthwork requirements. A width of 9 to 12m would more safety acommodate two or more outof con-trol vehicles. Reguarding comments on the most effective material, most respondents cited their own specification or referred to single graded, rounded pea gravel. The consensus essentially Is that single graded, well -rounded gravel is the most desirable material for use in arrester beds. The arrester beds should be constructed with a minimum aggregate depth of 30cm. Successful ramps have used depths between 30 and 90cm.