• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.05a
• /
• pp.46-51
• /
• 2000

Environmental quality regulations are used to establish the maximum permissible concentrations of heavy metals before a site can be deemed to be polluted or contaminated. This paper compares the results obtained by 0.IN HCl extraction and acid extraction method(HNO$_3$+HClO$_4$.HCl). The leaching efficiency of 0.1N HCl extraction is directly proportional to the final pH of leachate, due to the different solubilities of the heavy metals at different pH values, The severe differences between 0.1N HCl-extractable and total metal contents result mainly from the buffering effect of carbonates, present in sediment. samples. Application of sequential extraction experiments to some sediments collected from gully pot in Seoul illustrates a much stronger scavenging effect by Fe and Mn-hydroxides, carbonates and organic phases. As deduced from both sequential extraction and leaching experiments, the relative mobility of heavy metals is found to be: Mn>Zn>>Co>Cd>>Cu>Pb>Cr>Fe, in spite of large differences in heavy metal content and localization. Changes in the physicochemical environments (such as acidification) caused by a traffic accident may result in the severe environmental pollution of heavy metals of surrounding area( surface water and rivers).

• Proceedings of KOSOMES biannual meeting
• /
• 2004.05b
• /
• pp.13-18
• /
• 2004

The marine traffic congestion has increased due to the expansion of vessel traffic volume in Korean coastal waterway these days. Heavy traffic could bring serious marine casualties which cause the loss of human lives, properties and marine pollution in coastal area. In this paper. the probability analysis of marine casualties in Korean coastal To achieve this aim, clears up the cause of accident and examines closely the mutual relations among marine casualties, weather condition, and marine traffic volume. These casualties are classified into several pattens or the point of view of ship‘s size, ship’s type and ship‘s age and its characteristics of each patten are described in detail.

• Journal of Game and Entertainment
• /
• v.2 no.1
• /
• pp.8-16
• /
• 2006

The development of multicast communication services in the Internet is expected to lead a stable packet transfer even though On-Line Games generate heavy traffic. The Core Based Tree scheme among many multicast protocols is the most popular and suggested recently. However, CBT exhibits two major deficiencies traffic concentration or poor core placement problem. Thus, measuring the bottleneck link bandwidth along a path is important to understand the performance of multicast. We propose a method in which the core router's state is classified into SS(Steady State), NS(Normal State) and BS(Bottleneck State) according to the estimated link speed rate, and also the changeover of multicast routing scheme for traffic overload. In addition, we introduce Anycast routing tree, an efficient architecture for constructing shard multicast trees.

• Weed & Turfgrass Science
• /
• v.5 no.2
• /
• pp.88-94
• /
• 2016

Vehicular traffic on turf results in loss of green cover due to direct tearing of shoots and indirect long-term soil compaction. Protection of turfgrass crowns from wear could increase the ability of turf to recover from heavy traffic. Plastic turfpavers have been installed in trafficked areas to reduce soil compaction and to protect turfgrass crowns from wear. The objectives of this study were to evaluate traffic performance of turfgrasses (Zoysia matrella and Axonopus compressus) and soil mixture (high, medium and low sand mix) combinations on turf-paver complex. The traffic performance of turf and recovery was evaluated based on percent green cover determined by digital image analysis and spectral reflectance responses by NDVI-meter. Bulk density cores indicated significant increase in soil compaction from medium and low sand mixtures compared to high sand mixture. Higher reduction of percent green cover was observed from A. compressus (30-40%) than Z. matrella (10-20%) across soil mixtures. Both turf species displayed higher wear tolerance when established on higher sand (>50% sand) than low sand mixture. Positive turf recovery was also supported by complementary spectral responses. Establishment of Zoysia matrella turf on turfpaver complex using high sand mixture will result in improved wear tolerance.

• KIPS Transactions on Computer and Communication Systems
• /
• v.2 no.10
• /
• pp.421-426
• /
• 2013

As a greater amount of traffic have been generated on the Internet, it becomes more important to know the size of each flow. Many research studies have been conducted on the traffic measurement, and mostly they have focused on how to increase the measurement accuracy with a limited amount of memory. In this paper, we propose an explicit flow labeling technique that can be used to find out the names of the top flows and to increase the counting upper bound of the existing scheme. The labeling technique is applied to CSM (Counter Sharing Method), the most recent traffic measurement algorithm, and the performance is evaluated using the CAIDA dataset.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.10
• /
• pp.259-270
• /
• 2009

The objective of this study is to provide systematic design of the Korea's Integrated Road Transport System in intelligent transport systems. Integrated Road Transport System services support safety driving and traffic information for travellers, and rapid response of the system for emergency status not only dissemination of traffic for traffic but also flood, heavy snowfall, falling rocks, closed-road, collapse, accident and so on. Therefore, integrated road transport system service contributes national highway safety management system to the voice of the nation of integrated road transport system center service for user friendly.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2000.04b
• /
• pp.222-229
• /
• 2000

Malty bridges are severely damaged by the overloaded heavy vehicle and tile trend will become more serious because the traffic volume is continuously increasing. Currently, the vehicles with gross weights over 40 tons or axle weight over 10 tons are not allowed on the public road. However, this regulation is not based on a systemetic study on the bridge capacityand assumed to be much too conservative depending on the vehicle types ans bridge types. In this study, the permit weights of heavy vehicles of diverse axle spacings and axle load distribution are calculated considering the structural characteristics of bridge superstructures. In order to consider the various load effects of heavy weight vehicle crossings, three conditions are considered in the calculation of permit vehicle load. From the results, the permit vehicle weights of bridges are calculated and simplified formulas which can be used in the case when only the vehicle dimension are known are presented.

• The Korean Journal of Ecology
• /
• v.18 no.2
• /
• pp.285-293
• /
• 1995

The relationships among the contents of Pb, Zn, Cd, Cu and microbial biomass and activity of soil were investigated in Kyongbu, Yongdong, and Chungbu highways. The heavy metal concentrations were the highest in Kyongbu highway with high traffic density. The levels of these metals in soil in three highway sites were much higher than Mt. Kwank as control site. The highest concentrations of heavy metals were found in the upper layer of soil adjacent to the roadside. Dehydrogenase activity (DHA) and adenosine tri-phosphate (ATP) contents were generally lowest at distance of 0.5 m from the roadside. Simple regression analysis indicated that DHA and ATP contents were highly negatively correlated with Pb and Zn concentrations.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.70-71
• /
• 2006

IEC61850 which has comes to international standard for substation automation is designed with a station and process bus communication with Ethernet. In this paper, mentioning difference between official networks and substation networks, authors present the requirements for temperature, humidity and EMI characteristics. The properties which network switch should be satisfied and the technologies which make those requirements possible are also proposed. Additionally, we analysis the traffic pattern of communication services which IEC61850 supports. Based on the pattern, we propose a practical design example of IEC61850 based network for a 154kV substation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.129-135
• /
• 2000

Four types of land use were selected for sampling and study with different characteristics of heavy metal contamination during the period from August 1998 to June 2000. A series of studies have been carried out concerning the physicochemical characteristics of the sediments settling down in a gully pot to evaluate the contamination of Pb, Zn, Cd, Co, Cr and Cu. An examination of six elements indicated that Zn, Cu and Pb were the heavy metals severely impacted by anthropogenic input in Seoul. An assessment of 60 volatile organic compounds (VOCs) in urban runoff and ground water was conducted based on samples collected from 31 sites and 12 wells, respectively, in Seoul City. The higher levels of alkyl benzenes in urban runoff indicated that Seoul areas were mainly contaminated through traffic sources.