• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3723-3731
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• 2000

Recently, the growth of applications and services over high-speed Internet increase, ATM networks as wide area back-bone has been a major solution. The conventional TCP suite is still the standard protocol used to support upper application on current Internet and uses a window based protocol for flow control in the transport layer. When TCP data uses the UBR service in ATM layer, the control method is also buffer management. If a cell is discarded in ATM layer. one whole packet of TCP will be lost. Which is responsible for most TCP performance degradation and do not offer sufficiently QoS. To solve this problem, Several dropping strategies, such as Tail Drop, EPD, PPO, SPD, FBA, have been proposed to improve the TCP performance over ATM. In this paper, to improve the TCP fairness of end to end, we propose a packet dropping scheme algorithm using two fixed threshold. Under similar condition, we compared our proposed scheme with other dropping strategies. Although the number of VC is increased, simulation results showed that the proposed scheme can allocate more fairly each VC than other schemes.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.617-626
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• 2020

The drilling mud is essentially used in oil and gas development. There are several roles of using the drilling mud, such as cleaning the bottomhole, cooling and lubricating the drill bit and string, transporting the cuttings to the surface, keeping and adjusting the wellbore pressure, and preventing the collapse of the wellbore. The fragments from rocks and micro-sized bubbles generated by the high pressure are mixed in the drilling mud. The systems to separate those mixtures and to keep the uniformly maintained quality of drilling mud are required. In this study, the simulation is conducted to verify the performance of the mud tank's agitation capacity. The primary role of the mud tank is the mixing of mud at the surface with controlling the mud condition. The container type is chosen as a mud tank pursuing efficient transport and better management of equipment. The single- and two-phase simulations about the agitation in the mud tank are performed to analyze and identify the inner flow behavior. The convergence of results is obtained for the vertical- and axis-direction velocity vector fields based on the grid-dependency tests. The mixing time analysis depending on the multiphase flow conditions indicates that the utilization of a two-stepped impeller with a smaller size provides less time for mixing. This study's results are expected to be utilized as the preliminary data to develop the mixing and integrating equipment of the onshore drilling mud system.

• KIISE Transactions on Computing Practices
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• v.21 no.4
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• pp.290-298
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• 2015

This paper suggests a multi-agent message transport architecture based on the message-oriented middleware ZeroMQ. Compared with the other middlewares such as CORBA, Ice, and Thrift, ZeroMQ receives a good score in the evaluation of performance, QoS (Quality of Service), patterns, user friendliness, and resources. The suggested message transfer architecture borrowed many basic concepts like agent platform, AMS (Agent Management System), and MTS (Message Transfer System) from FIPA (Foundation for Intelligent Physical Agents) standard multi-agent specifications, and the architecture inherited the strength of the architecture from the multi-agent framework SMAF (Smart Multi-Agent Framework). The architecture suggested in this paper is a novel peer-to-peer architecture which is not known to the ZeroMQ community. In the suggested architecture, every MTS agent uses only one ZeroMQ router socket to support peer-to-peer communication among MTS agents. The suggested architecture can support closely collaborating software areas such as intelligent robots as well as the traditional application areas of multi-agent architecture. The suggested architecture has interoperability and scalability with the ZeroMQ devices and patterns.

• Journal of Advanced Navigation Technology
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• v.19 no.2
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• pp.98-102
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• 2015

In this paper are This paper is about the efficient use operational management plan for the metropolitan public Jamsil heliport. First, understand the general operations and facilities to Jamsil heliport and raised the issue for them. And, in cases such as urban offshore heliport Jamsil heliport in New York and Texas (USA), for example, which was presented for comparative analysis and Jamsil heliport in London (UK). Operations, research is seen against a facility to install and manage a couple of airfield operations based on the subject by presenting the alternatives, thereby causing the principal operating facilities, infrastructure and security facilities even suggest ways to enhance the standards. Unlike other countries, Jamsil heliport location characteristics were excluded from the study on the safety aspects related to flight operations and for this I'm a military airport facilities coexist in the neighborhood.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1539-1546
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• 2008

In the present age, a vehicle works important part in our lives and economical domain that transport people, freights, and everything. And both of its number and value are increasing more and more. But user's convenience, control system could not be archived improvement than technological success. In this paper, we suggest some kinds of administrative agendas; simplifying executive processes, designing vehicle information system using by RFID which includes Ubiquitous skill and optical communication network. Especially, this paper suggests public vehicle control model which ran simplify every executive processes of vehicle's life in the newest method. There are many kinds of RFID applicative products about transportation. And a dual invest should be interrupted for economical purpose. So we also proposes some way for problems of these types.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.237-246
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• 2015

In this paper, Improved productivity models of container terminal are provided by utilizing a simulation considering Tandem-lift Quay Crane and transport vehicle of container's high productivity 'Alternative ship-to-yard vehicles.' Feature of this method is deriving the data of tandem-lift Quay Crane and Alternative ship-to-yard vehicles, estimating the productivity model of tandem-lift Quay Crane by using regression analysis. Tandem-lift Quay Crane is equipment of loading and unloading to increase productivity approximately by 2 time existing (single, twin) Quay Crane by dealing with four 20ft containers or two 40ft containers at the same. Alternative ship-to-yard vehicles can transfer containers(4TEU) more than existing Yard Tractor. This paper is deriving the optimal combination showing the highest productivity by using simulation considering Tandem-lift Quay Crane and Alternative ship-to-yard vehicles on container terminals and developing estimating model of productivity by using regression analysis using data of simulation.

• Journal of Soil and Groundwater Environment
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• v.23 no.3
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• pp.27-42
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• 2018

It is important to identify the contaminant sources and to evaluate the fate and transport of heavy metals to crops in agricultural lands. This study was conducted to evaluate metal sources and its transfer and accumulation to crop in agricultural soils. Pollution indices were calculated and multivariate analysis was performed to identify metal sources. To evaluate transfer and accumulation of metals to crops, the contents of phytoavailable metals were evaluated by using single extraction method and the correlation between metal content and soil properties was analyzed. Also the BCF was quantitatively evaluated for investigating the metal transition to each crop grown in the research area. As a result, Cr, Ni, and Co were expected to be mainly derived from geologic factors due to weathering of certain parent rocks. The content of nickel in soils of the research area was slightly higher than that of the concern level criteria based on total concentration, but the amount transferred and accumulated in the crops was actually low. Understanding the contamination characteristics by investigating the pollution sources of heavy metals and its transfer and accumulation to crops through various evaluation techniques could provide important information for proper management of the agricultural land.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.3
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• pp.32-40
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• 2021

Underground information is difficult to visually check, which can lead to a huge accident in the event of a safety accident. Recently, the Ministry of Land, Infrastructure and Transport intends to reduce safety accidents caused by the aging or damage of underground facilities through the Special Act on Underground Safety Management. GPR is increasingly being used as a technology to acquire information in underground spaces that are difficult to see with the naked eye. However, GPR's location information is corrected by checking images of CCTV and GPS information acquired during exploration. This method has an average error of about 2 meters. In this works, We used LiDAR to calibrate the GPR information and found that the error was reduced from at least 7cm to up to 40cm. If accurate GPR information collected in the future is analyzed quickly using AI, etc., it will be able to collect and utilize underground information faster than it is now to secure safety.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.323-331
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• 2021

The relevance of the study implies the need to explain the main determinants of environmental policy, allowing countries to converge on a common working basis. The purpose of the research is to explore ways in which the environmental aspects of EU regions and territories can be shaped to apply to domestic environmental policy. A total of 997 representatives from the Ukrainian UTCs, who are involved in local environmental policy, participated in the survey. Results of the research. A hierarchy of regional environmental policy objectives has been identified. Three key principles of eco-policy development have been distinguished. The means of the innovative approach strategy implementation have been outlined (formation of the regional market of environmental services; organization of interaction between environmental agencies and market structures; establishment of environmental funds which finance environmental activities; implementation of the "collateral return" system; formation of a system of benefits and loans to enterprises that successfully implement the environmental policy). The means of the prognostic approach implementation strategy to the development of the region's environmental policy have been determined (the use of an orderly and successful long-term strategy of economic development of the region; obligatory consideration in the mechanisms strategy aimed at improvement of environmental management system of the region, interbranch impact of the projects implemented on the region's ecological situation; taking into consideration the economic and geographical peculiarities of the region, the necessary infrastructure, issues of the territorial location of the large enterprises in the region and their impact on the environment). The means of the traditional approach strategy implementation have been outlined (activity programs focused on solution of specific problems, rather than on the implementation of measures for environmental restoration and enhancement; nature conservation problems have interbranch, interdepartmental character due to unity of the region's ecosystem; tracking complexity of changing conditions (water basins, woodlands, air-mass transport), regional boundaries generally do not coincide with natural ecosystems boundaries). The practical significance of the study lies in providing recommendations for the implementation of certain aspects of Ukrainian UTC's environmental policy.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.175-181
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• 2021

Objectives: The correlation between the size of a leak hole, the volume of the leakage, and the range of influence was investigated for a hydrochloric acid tank-lorry. Methods: For the case of a tank-lorry chemical accident, KORA (Korea Off-site Risk Assessment Supporting Tool) was used to predict the leak rate and the range of influence according to the size of the leak hole. The correlation was studied using R. Results: As a result of analyzing the leak rate change according to the leak hole size in a 35% hydrochloric acid tank-lorry, as the size of the leak hole increased from 1 to 100 mm, the leak rate increased from 0.008 to 83.94 kg/sec, following the power function. As a result of calculating the range of influence under conditions ranging from 1 to 100 mm in size and 10 to 60 minutes of leakage time, it was found that the range spanned from a minimum of 5.4 m to a maximum of 307.9 m. As a result of multiple regression analysis using R, the quadratic function model best explained the correlation between the size of the leak hole, the leak time, and the range of influence with an adjected coefficient of determination of 0.97 and a root mean square error of 22.33. Conclusion: If a correlation database for the size of a leak hole is accumulated for various substances and under various conditions, the amount of leakage and the range of influence can easily be calculated, facilitating field response activities.