• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.652-657
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• 2004

As the real-time multimedia applications through Internet increase, the bandwidth available to TCP connections is oppressed by the UDP traffic, result in the performance of overall system is extremely deteriorated. Therefore, developing a new transmission protocol is necessary. The TCP-friendly algorithm is an example meeting this necessity. The TCP-friendly (TFRC) is an UDP-based protocol that controls the transmission rate based on the available round transmission time (RTT) and the packet loss rate (PLR). In the data transmission processing, transmission rate is determined based on the conditions of the previous transmission period. If the one-step ahead predicted values of the control factors are available, the performance will be improved significantly. This paper proposes a prediction model of transmission rate control factors that will be used for the transmission rate control, which improves the performance of the networks. The model developed through this research is predicting one-step ahead variables of RTT and PLR. A multiplayer perceptron neural network is used as the prediction model and Levenberg-Marquardt algorithm is used for the training. The values of RTT and PLR were collected using TFRC protocol in the real system. The obtained prediction model is validated using new data set and the results show that the obtained model predicts the factors accurately.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.17-31
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• 2004

The subway play an important part in serious traffic problems. However, because subway system is a closed environment, many serious air pollution problems occurred in subway stations and injured passenger's health. Therefor, it is a necessary to identify sources and to estimate pollutant sources in order to protect passenger's health and to keep clean subway environment. The purpose of this study was to analyze a air quality in the subway stations and to apply a new receptor methodology for quantitatively estimate of PM10 sources. In this study, the size distributions of particulate matters has been measured by using Aerosizer LD (U.S.A., API, Inc.). It's real time measurement capability of time-of-flight technique offers a significant advantage of user convenience and air pollution management. Also, the mass concentrations of PM 10 has been measured by using mini-vol portable sampler (U.S.A., Airmetrics Co.). The sampling performed in Seoul subway stations during the period of February 2000 and April 2000. The number distribution data used in this study consisted of 26 raw data sets in the Jongno-sam-ga station. Correlation Analysis can be used in subway stations for source separation and identification. Then, number contribution from each source is determined by the particle number balance (PNB). The mass concentration data used in this study consisted of 31 raw data in the 8 different stations. The mass contributions of PM10 sources in the concourse by using PMF/CMB model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.786-799
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• 2018

Recently, NFV has attracted attention as a next-generation network virtualization technology for hardware -independent and efficient utilization of resources. NFV is a technology that not only virtualize computing, server, storage, network resources based on cloud computing but also connect Multi-Tenant of VNFs, a software network function. Therefore, it is possible to reduce the cost for constructing a physical network and to construct a logical network quickly by using NFV. However, in NFV, when a new VNF is added to a running Tenant, authentication between VNFs is not performed. Because of this problem, it is impossible to identify the presence of Fake-VNF in the tenant. Such a problem can cause an access from malicious attacker to one of VNFs in tenant as well as other VNFs in the tenant, disabling the NFV environment. In this paper, we propose Auto-configurable Security Mechanism in NFV including authentication between tenant-internal VNFs, and enforcement mechanism of security policy for traffic control between VNFs. This proposal not only authenticate identification of VNF when the VNF is registered, but also apply the security policy automatically to prevent malicious behavior in the tenant. Therefore, we can establish an independent communication channel for VNFs and guarantee a secure NFV environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.299-301
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• 2015

As the new notification of Ministry of Public Safety and Security on the management of coastal VTS has been effective since April $20^{th}$ this year, all pleasure ships over 2 tons with AIS device(Automatic Identification System) must be the objects given certain vessel traffic service. So Tong-yeong Coastal VTS which has the largest number of pleasure ship throughout the country tries to review some problems that have emerged since the beginning and require consideration in all its aspects to prevent any maritime incidents related with pleasure ships and contribute largely to making our sea safe.

• Smart Structures and Systems
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• v.19 no.6
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• pp.653-663
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• 2017

The modal parameters of the deck of Runyang Suspension Bridge (RSB) as well as their relationships with wind and temperature are studied based on the data recorded by its Structural Health Monitoring System (SHMS). Firstly, frequency analysis on the vertical responses at the two sides of the deck is carried out to distinguish the vertical and torsional vibration modes. Then, the vertical, torsional and lateral modal parameters of the deck of RSB are identified using Hilbert-Huang Transform (HHT) and validated by the identified results before RSB was opened to traffic. On the basis of this, the modal frequencies and damping ratios of RSB during the whole process of Typhoon Masta are obtained. And the correlation analysis on the modal parameters and wind environmental factors is then conducted. Results show that the HHT can achieve an accurate modal identification of RSB and the damping ratios show an obvious decay trend as the frequencies increase. Besides, compared to frequencies, the damping ratios are more sensitive to the environmental factors, in particular, the wind speed. Further study on configuring the variation law of modal parameters related with environmental factors should be continued.

• Asian Journal of Atmospheric Environment
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• v.4 no.1
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• pp.9-19
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• 2010

The size distribution of airborne particulate matter (PM) and the concentrations of associated metallic elements were investigated in a busy urban region of a typical Korean industrial city. The PM concentrations measured during the spring, except for those in the size range of 1.1 to 2.1 ${\mu}m$, were slightly higher than the PM concentrations in the summer. Coarse particles contributed greatly to the variation in PM concentrations in the spring, while fine and submicron particles contributed largely to the variation in PM concentrations in the summer. The difference in size modes of the PM concentrations between spring and summer may be explained by the Asian dust effect and its accompanying wind direction and speed. Extremely high enrichment factors (EFs) values (6,971 to 60,966) for all of the size distributions in PM were identified for cadmium (Cd). High EFs values (12 to 907) were also identified for other heavy metals including Cr, Cu, Ni, Pb, Zn and Mn. Low EF values (0.29 to 8.61) were identified for Ca, K, Mg and Na. These results support the common hypothesis that most heavy metals in ambient PM have anthropogenic sources and most light metals have crustal sources. The results of principal components analyses and cluster analyses for heavy metals indicate that the principal sources of PM and metals were emissions from non-ferrous metal smelters, oil combustion, incinerators, vehicular traffic and road dust.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.149-152
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• 2007

According to the Ship Safety Act amended on 23 Mar. 2006, ships above certain size shall curry position indicating equipment The Vessel Monitoring (VMS) will help to upgrade the present search and rescue mechanism and reduce the loss et lives caused by marine accident Public Notice on standards for installation et ship position indicating equipment was published on 1 Nov. 2007 (MOMAF Notice No. 2007-88). In this paper, we would like to introduce the background, applying ships, prospect for currying ship position indicating equipment at the implementation aspect on Vessel Monitoring System.

• The Journal of Korean Association of Computer Education
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• v.9 no.6
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• pp.65-78
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• 2006

Recently, there has been much research to develope and apply RFID technology, which has a kcy role in the upcoming ubiquitous society, in many fields such as physical distribution, traffic control, medical service, and so on. However, there has been little research on a ubiquitous education or learning including 'u-Campuses' and 'u-Libraries'. Based on the characteristics of RFlD, this paper proposes a system for English learning required in globalization age. RFID tags and sensors utilize wireless communications to track the location and status information of the user to deliver English situated learning services. The current RFID-based system should use quite a different rniddleware, compared with a general-purpose middleware on server or desktop. The RFID system is used on a mobile PDA and consists of essential APIs such as reader and tag control, queue, and filter management.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.21-29
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• 2014

The dynamic information of radar and automatic identification system (AIS) for targets obtained from the traffic vessels operating in the north outer harbor and surrounding waters of Busan port, Korea. The target information was analyzed to investigate the potential collision risk resulting from the invalid true heading (HDT) information of AIS and the integration ambiguity in the graphic presentation of both tracked data sets for two systems. An integrated display system (IDS) for supporting the navigator of offshore fishing vessels was also developed to find possible maneuvering solutions for collision avoidance by comparing radar data with AIS data in real-time at sea. Consequently, the multiple functions of IDS can provide additional information that is potentially valuable for taking action to avoid the collision in offshore fishing vessels. However, the integration criteria of radar and AIS targets in the IDS must be carefully established to eliminate the fusion ambiguity in the graphic presentation of both AIS and radar symbols such as the one or two physical targets which are very close to each other.

• Korean Institute of Interior Design Journal
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• v.13 no.6
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• pp.123-131
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• 2004

The hospitals built In the seventies and eighties have gone through many different extensions and renovations. However, as there had been no prior projections of the future extensions, irrational processes in terms of interdepartmental functional relocations and space availability have recurred. As well, areas and departments are located in several wings, which bring about a decrease in interdepartmental functional linkage, causing a lot of confusion and trouble in hospital management. Through this research we acquire concluding remarks. 1) To restore functional linkage in the whole hospital, strategy of interdepartmental relocation with the clinic-in-the clinic concept is the measure to minimize the problems of the increase in interdepartmental functional linkage since the clinic-in-the clinic concepts minimize circulation and maximizes efficiency of hospital management by making all the dispersed wings as professional as possible. 2) The measure of smooth circulation in order to resolve the problems of patients' difficulty in identifying directions and in decrease in staff's work performance, which arises from the extensions without considering the traffic systems of the whole hospital involves introduction of linear circulation systems in which connections between departments or areas can be made centering main axes of circulation. It is also a responsive measure to enhance the functional linkage between buildings and efficiency of patient's ease in identification of directions.