• Environmental and Resource Economics Review
• /
• v.18 no.4
• /
• pp.767-785
• /
• 2009

This paper studies the effect of industrial waste water effluent charge reform. The goal of the present effluent charge system is to use environmental resources in an efficient way by charging the cost for removing emitted water pollutants. However, the present system is a type of regulation instead of providing economic incentives to the industry. That is, if a firm emits pollutants greater than the limit, it has to pay an amount greater than the cost of cleaning them taking into account the amount of waste water discharged, region, the number of violation and the level of density of pollutants. However, the excessive fees have resulted in the lowest ratio of revenue-to-effluent charge among all environmental charges. The paper estimates the effect of the change in effluent fee and revenue when the present effluent charge system is converted to one that offers economic incentives. The results show that the amount of waste water effluent charge is about four times larger than the estimated environmental cleaning cost. In addition, the results show that by modifying the effluent charge system, the ratio of revenue to effluent charge can be raised.

• Resources Recycling
• /
• v.26 no.5
• /
• pp.29-38
• /
• 2017

This study suggests optimal policy options for collection of used diapers through benchmarking of foreign countries and perception surveys. By conducting a survey, this study can identify the actual problems involved in the collection process and enhance the social acceptance toward diaper recycling policies. As a perception survey result, the economic burden of emission bags and sanitary issues were most important for the collection pilot test. Respondents thought that twice-a-week collection frequency was appropriate and that free emission bags might be preferable to participants. Currently municipal wastes are subject to waste management laws, which are applied by local governments. Diaper waste is categorized with municipal waste, so it seems to be treated by municipal waste systems. In terms of connection with government, possible alternatives were suggested to identify the relevant local government. Useful data could be obtained, to determine the economical viability of any future diaper recycling system implementation in the entire Seoul metropolis and adjacent areas of dense population.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.17 no.3
• /
• pp.101-108
• /
• 2007

We follow the promising recent results of deploying the public key cryptography in sensor networks. Recent results have shown that the public key algorithms are computationally feasible on the typical sensor nodes. However, once the public key cryptography is brought to the sensor network, security services such like key authentication will be critically required. In this paper we investigate the public key authentication problem in the sensor network and provide several authentication protocols. Our protocols are mainly based on the non-solvable overhearing in the wireless environment and a distributed voting mechanism. To show the value of our protocols, we provide an extensive analysis of the used resources and the resulting security level. As well, we compare our work with other existing works. For further benefit of our protocols, we list several additional applications in the sensor network where our protocols provide a sufficient authentication under the constrained resources.

• The KIPS Transactions:PartC
• /
• v.10C no.5
• /
• pp.641-646
• /
• 2003

Packet processing speed of routers as well as transmission speed of physical links gives a great effect on IP packet transfer rate in Internet. The router forwards a packet after determining the next hop to the packet's destination. IP address lookup is a main design issue for high performance routers. In this paper, we propose a partitioned compressed-trie for speeding-up IP address lookup algorithms based on tie data structure by exploiting path compression. In the ,proposed scheme, IP prefixes are divided into several compressed-tries and lookup is performed on only one partitioned compressed-trie. Memory access time for IP address lookup is lessen due to compression technique and memory required for maintaining partition does not increased.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2008.11a
• /
• pp.31-34
• /
• 2008

양방향 중계 채널(two-way relay channel)은 2명의 사용자가 중계기(relay)의 도움을 받아 서로 정보를 주고받는 통신 채널이다. 중계기에서는 각각의 사용자로부터 독립적으로 수신한 두 데이터 패킷에 네트워크 코딩 기법을 적용하고, 이를 통해 만든 패킷을 두 사용자에게 동시에 전송한다. 따라서 양방향 중계 채널에서는 기존의 협력 통신에 비해 보다 효율적인 자원의 사용이 가능하다. 한편, 다중 중계기 환경에서의 중계기 선택 기반 전송 방식은 시스템의 전력 제한(power constraint), 전송 패킷의 동기화(synchronization) 문제 등을 고려할 때 다중 중계기 기반 전송 방식보다 우수한 성능을 얻을 수 있다. 본 논문에서는 양방향 다중 중계기 채널에서 중계기 선택 기법을 제안한다. 양방향 중계 채널에서는 수신한 두 신호의 결합을 위해 중계기에서 네트워크 코딩 기법을 적용함으로써 중계기의 부담이 보다 증가하는 특징이 있다. 또한, 중계기는 신호 전송 시 두 사용자 모두에게 전송하게 되고 이로 인해 두 수신지와의 채널 조건을 모두 고려하여야 한다. 따라서 중계기 선택은 데이터 패킷의 전송이 시작되기 전에 분산된 방식(distributed method)으로 이루어지며, 각각의 사용자와 중계기 간 일시적(instantaneous) 채널 이득을 바탕으로 사용자-사용자 간(end-to-end) 경로 조건의 최대값을 계산하는 메트릭(metric)을 중계기 선택 기준으로 사용한다. 모의실험을 통해 제안된 중계기 선택 기법이 중계기의 개수에 해당하는 다이버시티 이득을 얻을수 있음을 보여준다.

• Journal of Korean Society of Transportation
• /
• v.11 no.1
• /
• pp.55-66
• /
• 1993

본 논문에서는 최근에 소개된 일반화중력모형(Generalized Gravity Model)파라메터의 최우추정치(Maximum Likelihood Estimates) 계산을 위한 새로운 알고리즘을 이론적으로 도출하였다. 개발된 알고리즘은 첫째 계산속도, 둘째 정밀도, 셋째 모형변수(예컨데 통행시간, 통행비용 등)들 간에 공선성(multicolinearity)이 존재할 경우의 계산능력, 넷째 대규모 스케일의 기.종점자료(large O-D Matrices)에 적용시의 계산능력, 다섯째 모형변수의 개수에 따른 계산능력의 평가기준에서 그 계산실적이 기존의 알고리즘과 비교 평가 되었다. 제안된 기법중에서 Modified Scoring 기법은 계산속도 및 정밀도등 앞서 나열한 계산능력의 평가기준 중 모든 부문에서 매우 탁월한 계산실적을 보이는 것으로 판명되었다. 따라서 최선의 추정치를 보장하는 최우추정기법이 대규모 스케일의 교통계획 적용에도 큰 비용(시간)부담없이 손쉽게 적용될 수 있게 되었다. 제안된 새로운 알고리즘의 적용시 교통계획분야에 가져올 수 있는 기대효과는 다음과 같다. 첫째, 최우추정법이 대규모 O-D 통행표에 쉽게 적용될 수 있고 또한 PC등 소형 컴퓨터에서도 처리가 쉽다. 둘째, 모형설명변수의 자유로운 선택등 통계적실험(experimentation)을 가능케 한다. 셋째, 중력모형이 내재되어 있는 결합모형(Combined Model)의 정산속도를 높인다. 넷째, IVHS(Intelligent Vehicle and Highway System)와 같은 분야에서 온라인(On-line)모형정산을 가능케 할 수 있다.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.45 no.3
• /
• pp.75-85
• /
• 2008

The DBMS are widely used in embedded systems. The flash memory is used as a storage device of a embedded system. The optimizer of existing database system assumes that the storage device is disk. There is overhead to overwrite on flash memory unlike disk. The block of flash memory should be erased before write. Due to this reason, query optimization model based on disk does not adequate for flash-aware database. Especially embedded system should minimize the consumption of energy, but consumes more energy because of excessive erase operations. This paper proposes new energy based cost model of embedded database and shows the comparison between disk based cost model and energy based cost model.

• School Mathematics
• /
• v.6 no.4
• /
• pp.373-388
• /
• 2004

This paper is to develop teaching procedures of low achievers in mathematics by using mindmaps. For this, we firstly set the teaching process on basis of literature research. And then we choose four subjects who had serious problems of both memory and mathematics achievement. we also choose the several topics of geometry and measure which could be a big burden of memory as stuff for mindmap activities. The results led us to that using mindmap activities in learning and teaching mathematics could effect on that kind of students' mathematical achievement and mathematical attitude as well as retention of mathematical concepts. It implied that we could develop individual programs for students who have different problems in learning mathematics.

• Journal of Korea Multimedia Society
• /
• v.7 no.2
• /
• pp.272-282
• /
• 2004

As Web services need to manage lots of information, it is indispensable to reduce server's load and speed up processing time. In this paper, we analyze the loading problems of server and suggest designing methods for light loaded Web applications based on .NET. The proposed methods include using a relative database to produce minimized modules and Stored Procedures to simplify SQL statements for reducing sever's load. Web pages are organized with scripts replacing server language, which improve server's capability by reducing loads. The execution time is also speeded up by organizing Web pages with User Controls. And XML/EDI is used for managing the effective exchange of documents. The proposed methods are implemented as an education management system and shows its effectiveness.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.6
• /
• pp.361-368
• /
• 2002

This paper presents a new data path synthesis algorithm which takes into account simultaneously three important design criteria: testability, design area, and total execution time. We define a goodness measure on the testability of a circuit based on three rules of thumb introduced in prior work on synthesis for testability. We then develop a stepwise refinement synthesis algorithm which carries out the scheduling and allocation tacks in an integrated fashion. Experimental results for benchmark and other circuit examples show that we are able to enhance the testability of circuits with very little overheads on design area and execution time.