• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.5
• /
• pp.29-41
• /
• 2016

V2X environment is the most popular part of the C-ITS based on the high technologies. To evaluate V2X environment technologies, radio communication range and market penetration rate of V2X vehicle are used. This paper studies the V2X environment considering various traffic congestion level, radio communication range and market penetration rate of V2X vehicle using the microscopic simulation (VISSIM) based on proper parameters and algorithm. In conclusion, V2X environment can reduce the congestion in proper traffic volume. However, if traffic volume is almost near the capacity, even V2X environment can't relieve the road condition. Furthermore, increase of the radio communication range does not always mean the decrease of the congestion and even with the small market penetration rate, it can also have an impact on the V2X environment. This result will be the foundation for the V2X environment much better.

• The KIPS Transactions:PartA
• /
• v.9A no.3
• /
• pp.371-378
• /
• 2002

The EMFG (Extended Mark Flow Graph) is known as a graph model for representing the discrete event systems. In this paper, we introduce input/output matrixes representing the marking variance of input/output boxes when each transition fires in an EMFG, and compute an incidence matrix. We represent firing conditions of transitions to a firing condition matrix for computing a firable vector, and introduce the firing completion vector to decide completion of each transition’s firing. By using them, we improve an analysis algorithm of the EMFG’s operation to be represented all the process of EMFG’s operation mathematically. We apply the proposed algorithm to the system repeating the forward and reverse revolution, and then confirm that it is valid. The proposed algorithm is useful to analysis the variant discrete event systems.

• Journal of the Korean Geotechnical Society
• /
• v.15 no.5
• /
• pp.229-240
• /
• 1999

The groundwater flow and grout flow in individual rock joint and jointed rock mass are studied using various methods of analysis such as (i) the finite difference method, (ii) channel network analysis and (iii) joint network analysis. The flow behaviour is investigated in two distinguishable scales of observation: one for a rough joint of a laboratory scale having variable aperture, and the other for field- scale rock masses having three sets of intermittent joints. In the former case, the aperture-dependent channel flow is identified for both water and grout flows. The comparison of the flow rate in a rough joint is made between the finite difference analysis and existing analytical solution. In the latter case, the effects of increasing number of joints on the groundwater inflow into a circular opening of various diameters are analyzed using both the joint network method and Goodman's analytic solution. Comparisons are made between the two methods. The boundary effects in the joint network method are discussed. The inhomogeneity of joint network and its impacts on the groundwater inflow are also discussed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.2C
• /
• pp.37-47
• /
• 2012

In this study, three centrifuge tests were performed to evaluate the feasibility of three physical quantities for detecting internal defect of earth core fill dam: pore water pressure, temperature, and electrical resistance. For this purpose, the measurement system for pore water pressure, temperature and electrical resistance on centrifuge model dams was established. Three centrifuge tests included a fill dam without internal defect and two other dams with artificial internal defect in the core. The effectiveness of seepage monitoring was examined during the centrifuge test. Test results showed the applicability of monitoring techniques to detect internal defect by monitoring pore water pressure, temperature, and electrical resistance.

• 한국해양학회지
• /
• v.21 no.1
• /
• pp.56-71
• /
• 1986

In order to clarify the influence of environmental factors on the phytoplankton cmmunity in Kyeonggi Bay, the hydrological and water quality data were obtained from 20cruises from May, 1981, to September, 1982 in this bay. Physical conditions at the mouth of the bay are more stable than those at the head of the bay. Temperatures and salinities of the upper part of the bay show great seasonal fluctuations due to the river discharge. By the extending effects of freshwater, a weak two-layer flow system is formed from the upper part of the bay to Palmi Island. In summer thermal stratification are formed in the middle and outer parts of the bay. In winter, However, the temperature shows no vertical temperature gradient. The inner bay and the vicinity area of Incheon Harbour are relatively polluted and eutrophicated due to both the runoff of freshwater from the Han River and the waste discharge from Incheon industrial complex. However, except the polluted area, the study areas are well oxygenated with more than 90% saturation.

• Journal of Korea Spatial Information System Society
• /
• v.9 no.1
• /
• pp.79-90
• /
• 2007

In this paper we proposed and implemented an incident detection model which combines fuzzy algorithm and traffic pattern in order to enhance the efficiency of incident detection for the highways with lamps. Most of the existing algorithms dealt with highways without lamps and can not be used for detecting incidents in the highways with lamps. The data used for model building are traffic volume, occupancy, and speed data. They have been collected by a loop sensor at 5 minutes interval at a point in the Internal Circular Highway of Seoul for the period of 3 months. In this model, the three parameters collected by sensor were fuzzified and combined with the daily traffic pattern of the link. The test of efficiency of the propsed model was performed by comparing the result of proposed model with traditional APID algorithm and fuzzy algorithm without the pattern data respectively. The result showed significant amount of improvement in reducing the false incident detection rate by 18%.

• The Journal of Society for e-Business Studies
• /
• v.25 no.1
• /
• pp.177-202
• /
• 2020

We propose the statistical modeling and empirical results that can be utilized to identify and interpret the structural factors of international arms exports in recent years. The building blocks of research comprise the following questions; which would be the explanatory variables for the changing trend of international arms exports, whether the statistical significance can be verified on those variables and how those are interpreted for the future policy making purpose. We use the dataset of top 40 countries from SIPRI's Arms Transfers Database and analyze several regression models which consist of explanatory variables derived from research hypotheses. The most noticeable result is that the national fiscal reserve is shown to have consistent influence on the arms exports changes. UN security council members' group also has dominant power to make a formation of arms exports market block. Furthermore, gross domestic product and net exports volume in the national economy would seem to be related to changes of international arms exports in post-2000 period as well.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.4
• /
• pp.91-103
• /
• 2016

The work zone traffic management is of keen interest because the unstable traffic stream in work zones leads to not only less productive traffic operational efficiency but also negative impacts on traffic safety. A promising method to address such issues is variable speed limit systems(VSLS). VSLS is expected to increase in throughput and to enhance safety by diminishing the crash potential. In addition, the usefulness of VSLS has been demonstrated by significant amount of existing literature. The objective of this study is to identify the effectiveness of VSLS based on a meta analysis technique. Throughput and travel speed were used as measures of effectiveness for VSLS in terms of the operational efficiency and safety respectively. Results showed that approximately 16.4% increase in throughput and 16.5% decrease in travel speed were obtainable by VSLS. The outcomes of this study would be useful in developing technologies and polices for better operation of VSLS.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.6
• /
• pp.88-100
• /
• 1998

In this paper, an algorithm for a real-time automatic fingerprint identification system is proposed. The fingerprint feature volume is extracted by considering distinct and local characteristics(such as intensity and image quality difference etc.) in fingerprint images, which makes the algorithm properly adaptive to various image acquisitionj methods. Also the matching technique is designed to be invariant on rotation, scaling and translation (RST) changes while being capable of real-time processing. And the classification of fingerprints is performed based on the ridge flow and the relations among singular points such as cores and deltas. The developed fingerprint identification algorithm has been applied to various sets of fingerprint images such as one from NIST(National Institute of Standards and Technology, USA), a pressed fingerprint database constructed according to Korean population distributions in sex, ages and jobs, and a set of rolled-than-scanned fingerprint images. The overall performance of the algorithm has been analyzed and evaluated to the false rejection ratio of 0.07% while holding the false acceptance ratio of 0%.

• Journal of the Korea Society for Simulation
• /
• v.17 no.2
• /
• pp.1-12
• /
• 2008

The major components of an engine are the cylinder block, cylinder head, crankshaft, connecting rod, and camshaft, which are more popularly known as the 5 C's. Thus, the engine shop usually consists of six sub-lines, including five machining lines and one assembly line. The flow line is the typical concept of the layout when the engineer designs the engine shop. This paper introduces a simulation study regarding the new crankshaft machining line in a Korean automotive factory. The major factors for designing the machining line are considered, and their effects on the system performance are evaluated with a three-dimensional(3D) simulation model that is developed with $QUEST^{(R)}$. The initial layout is analyzed using the simulation model, and we suggest some ideas for improvement.