• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.8
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• pp.544-554
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• 2014

In this paper, we introduce a cyber-physical intersection systems (CPIS) which intimately interconnects roadside units (RSU) located at intersection, on-board units (OBU) of moving vehicles, and smartphone apps. Based on the architecture of CPIS, we also present a green light optimal speed advisory based on the reference mobility models (GLOSA-RMM) to reduce intersection stopping time (IST) and fuel consumption. Based on several reference mobility models, the GLOSA-RMM determines the appropriate speed advisory by taking into account the current mobility and the intersection traffic light status, and then provides screen/voice GLOSA instructions to minimize the driver's distraction. We show that the GLOSA-RMM can reduce both the IST and the fuel consumption through the numerical results obtained from the prototype of the CPIS consisting of the OBU, the RSU and the smartphone app.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.4
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• pp.342-349
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• 2023

In this study, a numerical simulations were conducted to analyze the phase change behavior of a liquid hydrogen storage container. The effects of gravity direction and hydrogen filling rate on boil-off gas (BOG) in the storage container were investigated. The study employed the volume of fluid, which is the phase change analysis model provided by ANSYS Fluent (ANSYS, Canonsburg, PA, USA), to investigate the sloshing phenomenon inside the liquefied hydrogen fuel tank. Considering the transient analysis time, two-dimensional simulation were carried out to examine the characteristics of the flow and thermal fields. The results indicated that the thermal flow characteristics and BOG phenomena inside the two-dimensional liquefied hydrogen storage container were significantly influenced by changes in gravity direction and hydrogen filling rate.

• Journal of KIISE:Information Networking
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• v.34 no.2
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• pp.134-142
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• 2007

Several mobility supporting protocols have been proposed across OSI reference layers. Each protocol has similar or different characteristics based on its operating layer which affect a handover latency. In this paper, we analyze handover performance of most representative protocols in each layer. For analysis, we use SUBNET model based Markovian model and movement model. In result, difference of protocol handover latency is not occurred by DAD but also by security, movement detection, message processing time.

• STI Policy Review
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• v.6 no.1
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• pp.1-23
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• 2015

Based on the work of Anand et al. (2013) we measure inclusive income growth, which combines growth in gross domestic product (GDP) per capita and growth in the equity of the income distribution. Extending the work of Causa et al. (2014), we estimate a dynamic simultaneous structural equations model of GDP per capita and inclusive income on panel data for 63 countries over the 1990-2013 period. We estimate both equations in error correction form by difference GMM (generalized method of moments). Among the explanatory variables of the level and the distribution of GDP per capita we include R&D (research and development) expenditure per capita. In OECD countries we obtain a large positive effect of R&D on GDP. R&D is found to have a positive effect on the social mobility index but its impact on the income equity index at first decreases, then switches around to become slightly positive in the long run. In non- OECD countries, R&D is found to decrease inclusive income, mostly through a negative growth effect but also because of a slightly increasing income inequity effect.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1191-1201
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• 2010

In this paper, we analyze the impact on quitting one's first job based on "Graduates Occupational Mobility Survey" data given by Korea Employment Information Service. According to the survey, there are a large number of questionnaires on quitting one's first job and so it is not easy to choose among them. We will investigate model selection criteria and apply the procedure proposed by Shtatland et al. (2003) to identify the final model.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.64-74
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• 2021

Unmanned Aircraft Systems (UAS) are rapidly emerging not only as a key military power, such as surveillance and reconnaissance for military purposes but also as a new air transportation means in the form of Urban Air Mobility (UAM). Currently, airworthiness certification is carried out focused on the verification of technical standards for flight safety suitability of aircraft design in accordance with the Military Aircraft Flight Safety Certification Act and does not employ the model for operational risk assessment for mission areas and airspace. In this study, in order to evaluate the risk of the mission area from the perspective of the UAS operator, a risk assessment simulation has been conducted by applying the Specific Operations Risk Assessment (SORA) model to the operating environment of the Korean military UAS. Also, the validity of the SORA model has been verified through the analysis of simulation results, and a new application plan for airworthiness certification of the military unmanned aerial system has been presented.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.759-762
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• 2006

A simple SPICE model for the description of the on-current of low-temperature poly-silicon thin film transistors is proposed. By employing constant mobility, $V_GS$ dependent alpha parameter, and exponential kink effect, very good agreements between the model and measurement were obtained.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.32-48
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• 2023

Autonomous driving technology is shaping the future of personalized travel, encouraging personalized travel, and traffic impact could be influenced by individualized travel behavior during the transition of driving entity from human to machine. In order to evaluate traffic impact, it is necessary to estimate the total number of trips based on an understanding of individual travel characteristics. The Activity-based model(ABM), which allows for the reflection of individual travel characteristics, deals with all travel sequences of an individual. Understanding the relationship between travel and travel must be important for assessing traffic impact using ABM. However, the ABM has a limitation in the data hunger model. It is difficult to adjust in the actual demand forecasting. Therefore, we utilized a Tour-based model that can explain the relationship between travels based on household travel survey data instead. After that, vehicle registration and population data were used for correction. The result showed that, compared to the KTDB one, the traffic generation exhibited a 13% increase in total trips and approximately 9% reduction in working trips, valid within an acceptable margin of error. As a result, it can be used as a generation correction method based on Tour, which can reflect individual travel characteristics, prior to building an activity-based model to predict demand due to the introduction of autonomous vehicles in terms of road operation, which is the ultimate goal of this study.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.350-357
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• 2005

This study was conducted to investigate the downward mobility of pesticides using soil columns and to compare the experimental results with values predicted from Convective mobility test model. Nine pesticides such as metolcarb, molinate, fanobucarb, isazofos, diazinon, fenitrothion, dimepiperate, parathion and chlorpyrifos-methyl were used for leaching test in soil column for four soils; Jungdong (upland soil), Gangseo (paddy soil), Yesan (forest soil), and Sineom(upland, volcanic ash-derived soil) series. The peak concentrations leached from 10 cm-columns of three soils except Sineom series ranged 6.5 to 12.6 mg/L for metolcarb, 2.6 to 5.0 mg/L for molinate, 4.5 to 7.8 mg/L for fenobucarb, 0.39 to 1.36 mg/L for dimepiperate, 1.1 to 4.6 mg/L for isazofos, 0.01 to 0.14 mg/L for diazinon, lower than 0.01 to 0.70 mg/L for fenitrothion and lower than 0.01 to 0.44 mg/L for parathion. But chlorpyrifos-methyl was not leached from any soil columns. Elution volumes to reach the peak of metolcarb, molinate, fenobucarb, isazofos, diazinon, and dimepiperate in the leachate ranged 1.1 to 2.1 pore volume (PV), 1.6 to 3.3 PV, 1.6 to 3.3 PV, 2.1 to 4.4 PV, 6 to 15 PV, and 8 to 21 PV, respectively. On the same water flux conditions, convection times estimated by Convective mobility test model were coincided with results from soil column test in most of the soil-pesticide combinations applied. Based on convection times estimated by the model at standard conditions (water flux 1 cm/day), metolcarb was classified as most mobile, molinate, fenobucarb and isazofos as mobile or most mobile, dimepiperate as moderately mobile or mobile, diazinon as mobile, fenitrothion and parathion as slightly mobile or mobile and chlorpyrifos-methyl as immobile or slightly mobile.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.300-308
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• 2002

This study was conducted to investigate the downward mobility of pesticides using soil colunms and to compare the experimental results with predicted values from Convective mobility test model. Five pesticides including ethoprophos, procymidone, iprobenfos, isoprothiolane, and butachlor were subjected to soil column leaching test for three types of cultivation soils. The concentrations of ethoprophos, iprobenfos, procymidone, isoprothiolane and butachlor leached from soil column of 30 cm depth ranged $0.74{\sim}3.61mg/mL,\;0.36{\sim}1.67mg/L,\;0.16{\sim}0.84mg/L,\;0.16{\sim}0.67mg/L$ and lower than 0.15 mg/L, respectively. Elution volume to reach the peak of ethoprophos, iprobenfos, procymidone, isoprothiolane and butachlor in the leachate ranged $2{\sim}4PV,\;3{\sim}10PV,\;5{\sim}13PV,\;4{\sim}14PV\;and\;19{\sim}61PV$, respectively. Convection times predicted by Convective mobility test model at standard conditions were $9{\sim}18$ days for ethoprophos, $17{\sim}35$ days for iprobenfos, $24{\sim}54$ days for isoprothiolane, $21{\sim}65$ days for procymidone and $105{\sim}279$ days for butachlor. Based on these convection times, ethoprophos was classified as mobile or most mobile, isoprothiolane and procymidone as moderately mobile or mobile and butachlor as slightly mobile. On the same conditions, convection times from the model were coincided with those from soil column test in most of the soil-pesticide combinations applied. Therefore, Convective mobility test model could be applied to predict convection times of pesticides.