• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.419-423
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• 2006

In this study, acute toxicity of four pesticides (diazinon, iprodione, fenproparthrin, and myclobutanil) to Chinese bleak, Aphyocypris chinensis, and to study their adverse effects were conducted in static systems. The 96-hr $LC_{50}$ values were determined, as well as 95% confidence limits. The 96-hr $LC_{50}$ values of these chemicals derived for Chinese bleak were rank ordered from the most toxic to the least toxic technicals as follows: Fenproparthrin (0.003 mg $L^{-1}$)>Myclobutanil (9.1 mg $L^{-1}$)>Diazinon (14.1 mg $L^{-1}$)>Iprodione (31.8 mg $L^{-1}$), The data presented in this study indicate the acute toxicity tests carried out on only one fish species may lead to erroneous determination of water quality criteria and classification of test chemicals for environmental management and regulatory purpose. Therefore, more studies comparing the susceptibility of a variety of fish species to various toxicants are needed.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.957-965
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• 1999

그룹간 공동 작업이나 화상 회의와 같은 그룹 통신의 수요가 늘어나면서 멀티캐스팅을 이용한 효율적인 데이타 전송에 대한 요구가 증가하고 있다. 특히 오디오나 비디오 데이타와는 달리 공동 문서 작업이나 그룹간 문서 전송을 위한 데이타 처리를 위해서는 어느 정도의 시간 손실이 있더라도 신뢰성을 보장할 수 있는 멀티캐스트 프로토콜이 요구된다. 그러나 멀티캐스트 전송에서의 신뢰성을 보장하기 위하여 손실 패킷에 대한 재전송 패킷이 전체 그룹으로 멀티캐스트 되는 것은 네트워크 상에 트래픽을 폭증시키는 요인이 된다. 이에 본 논문에서는 지역 그룹에서의 오류 회복을 위한 재전송 제한 기법을 제안하여 손실 패킷의 재전송 과정에서 발생하는 트래픽의 폭주를 제어하고자 한다. 이것은 재전송 패킷이 중복없이 다중 수신자에게 전송될 수 있도록 하여 그룹 내의 재전송 패킷의 양을 줄이고 필요없는 중복 패킷이 네트워크의 효율을 저하시키는 것을 방지하고자 하는 데 그 목적이 있다. Abstract As the size and the geographic span of communication groups increases, efficient data transmission schemes using Multicast service become more and more essential. Especially, unlike audio and video applications, for some collaborative applications and other data delivery components which require ordered and lossless delivery of data, Reliable Multicast Service is needed to ensure consistent presentation across multiple views. Thus error recovery by retransmission of loss data is provided in order to guarantee the reliability of multicast transmission protocol. However, redundant retransmission packets by multicast may cause traffic implosion on the Internet and it can be aggravated with continuous retransmission.This paper describes a Restricted Retransmission Mechanism as an error recovery method of multicast service in a local group, which can handle traffic implosion in retransmission process. It reduces redundant retransmission packets flowing into a local group and supports reliable multicast transmission. The goal of this mechanism is to reduce retransmission packets and decrease the load for group members and networks.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.547-553
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• 2013

Zirconium oxide ($ZrO_2$) nano porous membranes were fabricated by electrochemical two-step anodization with an electropolished zirconium substrate in inorganic water-based and organic electrolyte systems containing small amounts of fluoride. Using two-step anodization and organic electrolytes, highly regular and ordered nanotubular $ZrO_2$ oxide layers can be compared with aqueous electrolytes. The morphology and size of the nano porous layers were characterized by FE-SEM (field emission scanning electron microscopy), XRD (X-ray diffraction), and EDS (energy dispersive spectroscopy). Luminescence properties were investigated by photoluminescence measurements.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.125-133
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• 2002

In this paper, we present an efficient broadcast protocol, called Btoken, that ensures total ordering of messages and atomicity of delivery in the large scaled distributed systems. Unlike the existing token-passing based protocol, Btoken does not circulate a token around the ring, instead, it uses three kinds of control messages for token transmission. The token has a sequence number field for broadcasting message, and the only site having the token can broadcast a message. When a site wishes to broadcast, It must send a message to the token site requesting the token. The token site sends a message with the token to the requester When the requester receives the token, it becomes the current token site and broadcasts a new message after setting sequence number derived from a field of the token into its message. Upon reception of it, any operating member is informed the position of the token site and will send token requesting message to the new token site. However, the other site may request the token to the old token site prior to receiving the broadcast message from the new token site. To resolve this problem, Btoken uses a message which is sent to the current token site by the old token site notifying who is the next token requester. Results of our simulation of the protocol show that Btoken is more efficient in the large scaled distributed system compared to existing broadcast protocols.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.391-398
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• 2001

To design and develop secure operating systems, the BLP (Bell-La Padula) model that represents the MLP (Multi-Level Policy) has been widely adopted. However, user\`s security level in the most developed systems based on the BLP model is inherited to a process that is actual subject on behalf of the user, regardless whatever the process behavior is. So, there could be information disclosure threat or modification threat by malicious or unreliable processes even though the user is authorized in the system. These problems can be solved by defining the subject as (user, process) ordered pair and by defining the process reliability. Moreover, when the leveled programs which exist as objects in a disk are executed by a process and have different level from the process level, the security level decision problem occurs. This paper presents an extended BLP (E-BLP) model in which process reliability is considered and solves the security level decision problem. And this model is implemented into the Linux kernel 2.4.7.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.3
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• pp.30-41
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• 2022

With the advent of autonomous driving, personal mobility, drones, and smart roads, it is necessary to respond to changes in the road traffic environment in the road guidance system. However, the use of road signs to guide the road is decreasing compared to the past due to the advent of devices such as navigation and smartphones. Therefore, in this study, a large-scale survey was conducted to derive road sign issues and usage plans to respond to future changes. Based on this, this study presented a strategy to diversify road sign functions by analyzing the factors affecting the use of road signs by citizens. As a result, first, it is necessary to provide real-time variable road guidance information that reflects user needs such as traffic, weather, and local events. Second, it is necessary to informatize digital road signs such as reflecting maps with precision. Third, it is necessary to demonstrate road guidance in a virtual environment that reflects various future mobility and road environments.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.12-25
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• 2016

The purpose of this study is providing an evaluation criteria for appropriateness of bicycle riding path considering trip purpose based on cyclist's response of importance and satisfaction. The survey presents a quantified criteria of evaluating appropriateness of the bicycle path by investigating difference of impotance and satisfaction between two purposes among 5 selected influence factors about bicycle lane and bicycle parking facility, and in case of commuting purpose, information of destination is additionally considered. All the influence factors are analyzed by Analytical Hierarchy Process (AHP) which yields importance. For the factors which have a huge difference between two purposes, evaluation criteria using a GIS Data of respondent's path and satisfaction of each factors is developed, and other factors are made it by reviewing literature. The importance analyzed by AHP and evaluation criteria can provide a path based LOS for cyclist, and this information can be improved through user's response from app or search engine in the future. and by considering individual's evaluation, it can provide individually specified information.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.52-62
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• 2013

Design Hourly Factor(DHF) is defined as the ratio of design hourly volume(DHV) to Average Annual Daily Traffic(AADT). Generally DHV used the 30th rank hourly volume. But this case DHV is affected by holiday volumes so the road is at risk for overdesigning. Computing K factor is available for counting 8,760 hour traffic volume, but it is impossible except permanent traffic counts. This study applied three method to make DHF, using 30th rank hourly volume to make DHF(method 1), using peak hour volume to make DHF(method 2). Another way to make DHF, rank hourly volumes ordered descending connect a curve smoothly to find the point which changes drastic(method 3). That point is design hour, thus design hourly factor is able to be computed. In addition road classified 3 type for national highway using factor analysis and cluster analysis, so we can analyze the characteristic of DHF by road type. DHF which was used method 1 is the largest at any other method. There is no difference in DHF by road type at method 2. This result shows for this reason because peak hour is hard to describe the characteristic of hourly volume change. DHF which was used method 3 is similar to HCM except recreation road but 118th rank hourly volume is appropriate.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.1
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• pp.18-25
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• 2017

Damage of both life and property has been increased by natural disaster under the influence of climate change, thus many natural disaster vulnerability researches have been carried out to make adaptation policy and impact assessment of climate change recently. Their method for assessing vulnerability usually have used proxy variables for making vulnerability indices. However, because their results were too qualitative and relative it tends to be hard to make absolute comparison and establish standard of prevention or adaptation ability. Accordingly, this study aimed at quantifying natural disaster vulnerability using emergy through recognizing disaster as the relations between order and disorder by system approach. As a result, ordering energy (4.66E+22 sej/yr) and ordered structure (1.98E+22 sej) of Busan in 2003 and disordering energy (7.80E+18 sej), disordered parts (4.55E+20 sej) and rebuilding energy (3.87E+20 sej) by typhoon Maemi were analysed. And then, this was compared with Hurricane Andrew in Dade County. Through this comparison, if the prevention ability of Busan increases, disordered parts can be reduced against the more powerful disordering energy. Also, prevention for additional damages by disaster is needed to practical rebuilding action. In conclusion, it was able to figure out the impact of disaster quantitatively by natural systems and urban systems showing as common measure. Based on this study and further research to make effective prevention for how much prevention ability should be increased will contribute to producing the scientific data for disaster management policy in future.

• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.59-71
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• 2019

Korea's average annual working hours are among the highest in the OECD. Such long-term work has been a factor that reduces the quality of life by discouraging workers' productivity and interrupting the compatibility of work and family, prompting the government to encourage flexible work systems, such as increasing part-time jobs, but a lack of quality part-time jobs. Part-time work enables flexible labor for workers, but at the same time, workers will involuntarily opt for part-time work as they have poor working conditions and negative social views. In this respect, the effect of the working type on an individual's life is expected to be different. In addition, for women, gender gaps exist in the labor market and the impact of part-time work on life satisfaction is expected to differ from men in terms of working and family alike. Using the data from the 2017 "Seoul Survey Urban Policy Indicator Survey", the ordered logistic regression model was used to analyze the cross-effect of working type and sex on satisfaction. The analysis of the study showed that when other factors were controlled, life satisfaction was high in the order of fulltime female, full-time male, part-time female, and part-time male. In addition, further analysis shows that the parttime female workers have the highest probability of choosing low life satisfaction, while the probability of choosing high life satisfaction is the lowest, and full-time male workers have the lowest probability of choosing low life satisfaction, while the highest probability of choosing high life satisfaction is the highest.