• Proceedings of the Korea Association of Information Systems Conference
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• 2000.11a
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• pp.6-11
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• 2000

수출입 관련 항만물류업무 처리의 효율화를 위해 1996년부터 도입된 EDI는 서류없이 각종 항만물류 및 통관업무를 효율적으로 처리하는데 큰 기여를 하고 있다. 그러나 기존의 방식은 VAN EDI 로써 폐쇄적인 VAN 망을 통하여 EDI VAN사업자가 사용자의 EDI문서를 관련 정부기관에 중계만을 하여 EDI문서에 나타난 각종 데이터의 누적을 통한 물류정보서비스는 제공되고 있지 않다. 한편, EDI를 수신한 각 정부기관에서는 필요한 물류요약정보를 얻기 위해 해당 EDI 문서에서 추출한 데이터를 저장하는 운영 데이터베이스에 접근하여 필요한 요약 정보를 리포트 형태로 프로그램하여 생성하고 있어 정보제공의 시간지연과 프로그램 업무의 과중 및 운영 데이터베이스에 대한 부하가 발생하고 있다. 본 논문의 목적은 이러한 상황에서 수출입 항만물류와 관련한 다차원 정보를 실시간제공하기 위한 데이터웨어하우스를 구축하는데 있다. 일반적으로 데이터웨어하우스는 운영데이터베이스로부터 다차원 구조의 데이터웨어하우스로 데이터를 추출, 전환, 복사함으로써 이루어지지만, 본 연구에서는 EDI 수신 기관의 운영데이터베이스보다 더 원천 데이터인EDI 문서로부터 데이터웨어하우스로 데이터 변환을 함으로써 항만물류 데이터웨어하우스의 데이터 추출 단계를 한 단계 줄였다. 현재 VAN EDI 방식은 그 폐쇄성과 비용 때문에 향후 인터넷을 이용한 XML/EDI로 기술 이전될 것이 예상되며 이러한 상황에서VAN EDI 포맷이 아닌 XML/EDI 문서로 부터 데이터웨어하우스로의 전환을 구현하였다. 본 연구에서는 관세청의 수출통관 EDI에 대해 이를 XML/EDI 로 XML 스키마를 정의하고 이로 생성된 XML 문서를 SQL 서버로 구현된 OLAP 용 데이터웨어하우스로 전환하였다. 본 연구를 통해 XML을 이용한 EDI체제에서 전자문서전송기능과 정보제공기능을 위한 데이터웨어하우스의 연동을 동해 EDI시스템을 다차원 의사결정정보 시스템과 통합하게 하여, 향후 인터넷 기반 XML/EDI 중계서비스에 있어 물류정보서비스도 원활하게 제공할 수 있게될 것으로 기대된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.20-26
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• 2010

The downlink scheduling algorithm has a great impact on the performance of mobile telecommunication system. In proportional fairness (PF) scheduling algorithm, the resource is allocated proportionally to the quality of wireless channel. Thus, PF has difficulty in servicing the users having more downlink traffic. One can allocate the resource proportionally to the accumulated queue length. However, this leads to system throughput degradation since the users having low channel quality get more and more resource allocated due to accumulation property of queue. In this paper, we propose a new downlink scheduling algorithm, which extends PF algorithm by incorporating downlink traffic arrival rate. The proposed algorithm can effectively cope with users having more downlink traffic, and maintain high system throughput by eliminating accumulation effect in the algorithm. With computer simulations, it is verified that the proposed algorithm performs better than existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.957-964
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• 2010

In this paper, we propose an indoor positioning algorithm based on 3 points near field angle-of-arrival estimation without side information. The conventional angle-of-arrival based positioning scheme requires the distance between the listener and the center of two points which is obtained by a received signal strength based range estimation. However, a received signal strength is affected by structure of room, placement of furniture, and characteristic of signal, these effects cause a large error to estimation of angle. In this paper, the proposed positioning scheme based on near field angle-of-arrival estimation can be used to estimate the position of listener without a prior distance information, just using time-difference-of-arrival information given from 3 points microphones. The performance of the proposed scheme is shown by cumulative distribution function of root mean squared error.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.138-144
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• 2009

This paper proposes an efficient scheme to estimate the channel parameters such as channel gain and delay for the IEEE802.15.4a LR-UWB systems. Sliding window (SW) method is generally used for the channel estimation of LR-UWB systems, which extracts the channel parameters by performing the cross-correlation with the repeatedly transmitted signal. However, the SW method experiences the severe performance degradation because the cross-correlation is performed just once for the received signal. In this paper, we propose a novel channel estimation scheme, which can achieve a great performance gain by performing the cross-correlation repeatedly with the repeated receive signal. In order to verify the performance gain of the proposed scheme, we performed the intensive simulation with the Saleh-Valenzuela channel model. Simulation results show that the proposed scheme has a performance improvement of 4dB compared to the conventional SW channel estimation scheme.

• The Transactions of the Korea Information Processing Society
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• v.3 no.3
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• pp.501-511
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• 1996

Typical integrated service digital network(ISDN) switching systems have several shortcomings including cumulated long call set-up delay and difficulty in higher speed packet communication. The problems come from the nature of X.25 packet swiching technique used in the systems. In this thesis, to solve the above problems, the use of frame relay service within the TDX-10 ISDN switching system is proposed and a frame handling susbsystem(FHS) is designed in order to support the high speed frame relay service in the TDX-10 switching systems. In the proposed TDX-10 architecture, the 64 Kbps packet communication can be executed more ef- ficiently and high speed packet communication is allowed. To measure theperformance characteristics of the proposed systemand to compare the performance with that of the proposed system is superior to that of the existion system and to compare the performance with that of the proposed system is superior to that of the existing system. The proposed switching system offers a seamless evolutionalry path from Narrowband-ISDNto Broadband-ISDNsince itallows anefficient channelutilization and speed packet communication.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.6
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• pp.1055-1065
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• 2023

Recently, various studies using deep reinforcement learning (deep RL) technology have been conducted to solve complex problems using big data collected at industrial internet of things. Deep RL uses reinforcement learning"s trial-and-error algorithms and cumulative compensation functions to generate and learn its own data and quickly explore neural network structures and parameter decisions. However, studies so far have shown that the larger the size of the learning data is, the higher are the memory usage and search time, and the lower is the accuracy. In this study, model-agnostic learning for efficient federated deep RL was utilized to solve privacy invasion by increasing robustness as 55.9% and achieve 97.8% accuracy, an improvement of 5.5% compared with the comparative optimization-based meta learning models, and to reduce the delay time by 28.9% on average.

• Industry Promotion Research
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• v.9 no.1
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• pp.47-55
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• 2024

In the transportation sector, reducing total vehicle mileage and passenger vehicle traffic are proposed as strategies to achieve carbon neutrality. To achieve this, MaaS services must be actively promoted with the goal of revitalizing public transportation. In order to promote MaaS, individual movement data is required, such as the individual's means of movement, route, and conversion of the individual's means of use. However, in Korea, there are legal limitations in collecting and utilizing data on individual movements. As the right to request transmission of personal information was newly established in the revised Personal Information Protection Act in 2023, a law was established to collect and utilize data on individual movements. However, enforcement ordinance, detailed rules, instructions, guidelines must be prepared, and the standardization of data format and transmission system for collecting my data needs to take precedence.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.71-78
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• 2000

Preferential flow has recently been the subject of increasing interest because these phenomena contribute to solute transport in soils. Commonly, preferential flow paths are associated with macropores or highly structured soils. We presented an analysis of the measured breakthrough curves (BTCs) of $Cl^-$ and $Cu^{2+}$ ions to test the occurrence of preferential flow in soils using miscible displacement technique under steady flow conditions. We also analyzed soil water retention curves and from this curves induced cumulative pore size distribution of undisturbed soils, which sampled from Ap1, B1, and C horizons of Songjeong series soils (the fine loamy, mesic family of Typic Hapludults). In this study, miscible displacement experiment on C horizon was excluded, because it is structureless sandy loam with saturated hydraulic conductivity of $5.2cmhr^{-1}$. The saturated hydraulic conductivity of Ap1 horizon was $2.0cmhr^{-1}$, which was about 7 times higher than that of B1 horizon ($0.27cm hr^{-1}$). Cumulative pore size distribution predicted that Ap1 horizon had more macropores (pore diameter larger than $49{\mu}m$, equivalent to -6 kpa of soil matric potential) than B1 horizon. The hydrodynamic dispersion coefficient from chloride BTCs was estimated as $1.3cm^2hr^{-1}$ for B1 and $34cm^2hr^{-1}$ for Ap1 horizon. However the retardation factors of B1 and Ap1 horizon were significantly different, i.e. 1 and 0.6, respectively, which means that there was distinct partition between mobile water and immobile phase in Ap1 horizon. The copper retardation effect of Ap1 horizon was less than that of B1 horizon, even though cation exchange capacity of Ap1 horizon was higher than that of B1 horizon. Thus, breakthrough curves of $Cl^-$ and $Cu^{2+}$ obviously showed the probability that preferential flow would occur in Ap1 horizon.

• Childhood Kidney Diseases
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• v.4 no.1
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• pp.84-91
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• 2000

Purpose: To improve the recovery of growth deficit after renal transplantation in children, we analysed the factors affecting height growth after renal transplantation. Methods: We reviewed medical records of fifty-six children in whom height data were available for three years after transplantation. All height data were converted into Z-scores. We analyzed the effects of sex, age at transplantation, cumulative mean steroid dose for 3 years, serum creatinine levels, height at transplantation, donor source and history of prior dialysis on patients' z-scores and delta Zs. Results: The Z-scores at transplantation were lower in patients of younger age (P=0.007). When baseline Z-scores were lower, the delta Zs were higher (P<0.01), but the Z-scores after transplantation were still lower (P<0.001). According to the analysis of the partial correlation coefficients, Z-scores and delta Zs at 1 year after transplantation were higher in groups of younger age and of lower steroid dosages (P<0.05). The delta Zs at 6 month and 1 year after transplantation were lower in the group with abnormally higher serum creatinine (P<0.05). There was no difference in Z-scores between groups of different genders, donor sources, and histories of previous dialysis. Conclusion: The children of younger age, on lower steroid dosage, with less growth retardation at transplantation, and with normal graft function had better height growth recoveries after renal transplantation.

• Korean journal of applied entomology
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• v.55 no.1
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• pp.35-43
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• 2016

The temperature-dependent development of Metcalfa pruinosa overwintering eggs was investigated at ten constant temperatures (12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and $35{\pm}1^{\circ}C$, Relative Humidity 20~30%). All individuals collected before April 13, 2012 failed to develop into first instar larvae. In contrast, some individuals that were collected on April 11, 2013 successfully developed when reared under $20{\sim}32.5^{\circ}C$ temperature regimes. The developmental duration was shortest at $30^{\circ}C$ (13.3 days) and longest at $15^{\circ}C$ (49.6 days) in the fourth collected colony (April 26 2013). Developmental duration decreased with increasing temperature up to $30^{\circ}C$ and development was retarded at high-temperature regimes ($32.5^{\circ}C$). The lower developmental threshold was $10.1^{\circ}C$ and the thermal constant required to complete egg overwintering was 252DD. The Lactin 2 model provided the best statistical description of the relationship between temperature and the developmental rate of M. pruinosa overwintering eggs ($r^2=0.99$). The distribution of the developmental completion of overwintering eggs was well described by the 2-parameter Weibull function ($r^2=0.92$) based on the standardized development duration. However, the estimated cumulative 50% spring emergence dates of overwintering eggs were best predicted by poikilotherm rate model combined with the 2-parameter Weibull model (average difference of 1.7days between observed and estimated dates).