• 한국농림기상학회지
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• 제25권4호
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• pp.311-325
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• 2023

본 연구는 가리왕산, 유명산에 자생하는 주요 밀원수종인 음나무, 벚나무류, 피나무류 및 쪽동백나무를 대상으로 머신러닝기법(i.e., MaxEnt)을 활용하여 서식지 적합성 분석을 수행하였다. 분석 결과, 모형의 예측정확도인 AUC 값은 대부분의 밀원수종이 0.7 이상이었으며, 주요 환경 변수에 대한 반응 곡선 결과 주요 밀원수종의 서식지 적합성에 영향을 미치는 환경적 요인은 고도, 연평균 강수량, 연평균 기온으로 나타났다. 이는 고도 구배에 따른 기후 인자가 주요 밀원수종의 분포 패턴 설명에 있어 주요한 환경 변수임을 의미한다. 본 연구는 우리나라 밀원수림의 조성 및 관리 전략수립 뿐만 아니라 밀원수종의 분포도 제작 시 근거 자료로써 기여할 수 있을 것이다. 향후 다양한 층위에서의 꿀과 화분의 생산량 증대 및 꿀의 주년 생산을 위해서는 생물학적 변수를 반영한 다양한 지역 단위의 추가적인 데이터 수집 및 분석이 필요할 것이다.

• 전기학회논문지P
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• 제53권3호
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• pp.122-128
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• 2004

This paper presents a control approach for designing a fuzzy-PI controller for a synchronous generator excitation and SVC system. A combination of thyristor-controlled reactors and fixed capacitors(TCR-FC) type SVC is recognized as having the most flexible control and high speed response, which has been widely utilized in power systems, is considered and designed to improve the response of a synchronous generator, as well as controlling the system voltage. A Fuzzy-PI controller for SVC system was proposed in this paper. The PI gain parameters of the proposed Fuzzy-PI controller which is a special type of PI ones are self-tuned by fuzzy inference technique. It is natural that the fuzzy inference technique should be based on humans intuitions and empirical knowledge. Nonetheless, the conventional ones were not so. Therefore, In this paper, the fuzzy inference technique of PI gains using MMGM(Min Max Gravity Method) which is very similar to humans inference procedures, was presented and applied to the SVC system. The system dynamic responses are examined after applying all small disturbance condition.

• 대한전자공학회논문지SD
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• 제38권1호
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• pp.69-78
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• 2001

본 논문은 휴대용 고속 페이징 시스템을 위한 FLEXTM 프로토콜 신호 처리기의 설계 및 FPGA 구현에 관한 것이다. 본 논문에서는 A/D 변환기의 입력 단에서 수신된 interleaved 4-level 비트 심볼 데이터의 동기를 위한 심볼 동기 알고리듬과 (31,21)BCH 부호에 대해 실시간 2중 오류정정이 가능한 개선된 복호 알고리듬을 제안한다. 설계된 프로토콜 신호처리기는 6개의 기능 모듈로 구성되어 있으며, 각 모듈은 VHDL(VHSIC Hardware Description Language)로 모델링을 행하였다. 제안된 프로토콜 신호기는 Axil-320 워크스테이션 상에서 Synopsys/sup TM/툴을 이용하여 기능 시뮬레이션 및 논리합성(Altera 10K 라이브러리 이용)을 수행하였다. 논리합성 결과 전체 셀의 수는 약 2,631이었다 또한, 설계된 FPGA 칩의 설계검증을 위하여 Altera MAX+ PLUS Ⅱ 상에서 타이밍 시뮬레이션을 수행하였다. PCB 상에서 testbed를 구축한 후, Logic Analyzer를 이용하여 제작된 FPGA 칩의 동작상태를 확인하였고, 실험을 통하여 제작된 칩이 정확히 동작함을 확인하였다.

• Journal of Veterinary Science
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• 제21권5호
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• pp.60.1-60.11
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• 2020

Background: Tumor-associated neoangiogenesis is a crucial target for antitumor therapies. Thalidomide (TAL) is a promising anti-neoangiogenetic drug that has recently been used in the treatment of several malignancies in dogs. Objectives: The aim of the study was to assess the pharmacokinetics of TAL after single oral administration in dogs. Additionally, the influence of feeding on the pharmacokinetic profile of TAL in dogs has been preliminarily investigated. Methods: Six healthy adult female Labradors were enrolled according to a randomized single-dose, 2-treatment, 2-phase, paired 2 × 2 cross-over study design. The dogs were administered a single 400 mg capsule of TAL in fasted and fed conditions. Blood was collected from 15 min to 48 h after dosing, and TAL quantified in plasma by a validated high-performance liquid chromatography method. The pharmacokinetics of TAL were analyzed using a non-compartmental approach. Results: TAL concentration was quantifiable up to 10 h and 24 h after fasted and fed conditions, respectively. C_max (fasted, 1.34 ± 0.12 ㎍/mL; fed, 2.47 ± 0.19 ㎍/mL) and T_max (fasted, 3 h; fed, 10 h) differed substantially between the 2 groups. AUC and t_1/2λz were significantly higher in fed (42.46 ± 6.64 mg × h/L; 17.14 ± 4.68 h) compared to fasted (12.38 ± 1.13 mg × h/L; 6.55 ± 1.25 h) dogs. The relative oral bioavailability of TAL for the fasted group was low (36.92% ± 3.28%). Conclusions: Feeding affects the pharmacokinetics of oral TAL in dogs, showing a delayed, but higher absorption with different rate of elimination. These findings are of importance in clinical veterinary settings, and represent a starting point for further related studies.

• The Korean Journal of Physiology and Pharmacology
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• 제21권1호
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• pp.107-115
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• 2017

Over the last decade, physiologically based pharmacokinetics (PBPK) application has been extended significantly not only to predicting preclinical/human PK but also to evaluating the drug-drug interaction (DDI) liability at the drug discovery or development stage. Herein, we describe a case study to illustrate the use of PBPK approach in predicting human PK as well as DDI using in silico, in vivo and in vitro derived parameters. This case was composed of five steps such as: simulation, verification, understanding of parameter sensitivity, optimization of the parameter and final evaluation. Caffeine and ciprofloxacin were used as tool compounds to demonstrate the "fit for purpose" application of PBPK modeling and simulation for this study. Compared to caffeine, the PBPK modeling for ciprofloxacin was challenging due to several factors including solubility, permeability, clearance and tissue distribution etc. Therefore, intensive parameter sensitivity analysis (PSA) was conducted to optimize the PBPK model for ciprofloxacin. Overall, the increase in $C_{max}$ of caffeine by ciprofloxacin was not significant. However, the increase in AUC was observed and was proportional to the administered dose of ciprofloxacin. The predicted DDI and PK results were comparable to observed clinical data published in the literatures. This approach would be helpful in identifying potential key factors that could lead to significant impact on PBPK modeling and simulation for challenging compounds.

• Journal of Advanced Marine Engineering and Technology
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• 제36권5호
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• pp.645-661
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• 2012

Recently, pirates are infesting on the sea and they have been hijacking the several vessels for example Samho Dream and Samho Jewelry of Korea. One of the items to reduce the risk is to adopt the invader detection system. If the pirates break in to the ship, the detection system can monitor the pirates and then call the security alarm. The crew can gain time to hide to the safe room and the report can be automatically sent to the control room to cope with the situation. For the invader detection, an unmanned observation system was proposed using the image detection algorithm that extracts the invader image from the recording image. To detect the motion area, the difference value was calculated between the current image and the prior image of the invader, and the 'AND' operator was used in calculated image and edge line. The image noise was reduced based on the morphology operation and then the image was transformed into morphological information. Finally, a neural network model was applied to recognize the invader. In the experimental results, it was confirmed that the proposed approach can improve the performance of the recognition in the invader monitoring system.

• ETRI Journal
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• 제39권2호
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• pp.275-283
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• 2017

A green technology for reducing energy consumption has become a critical factor in ICT industries. However, for the telecommunications sector in particular, most network elements are not usually optimized for power efficiency. Here, we propose a novel energy-efficient packet switching method for use in an IP network for reducing unnecessary energy consumption. As a green networking approach, we first classify the network nodes into either header or member nodes. The member nodes then put the routing-related module at layer 3 to sleep under the assumption that the layer in the OSI model can operate independently. The entire set of network nodes is then partitioned into clusters consisting of one header node and multiple member nodes. Then, only the header node in a cluster conducts IP routing and its member nodes conduct packet switching using a specially designed identifier, a tag. To investigate the impact of the proposed scheme, we conducted a number of simulations using well-known real network topologies and achieved a more energy- efficient performance than that achieved in previous studies.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.638-648
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• 2013

Together with the GPS-based approach, geo-location through mobile communication networks is a key technology for location-based service. To save the cost, most geo-location system is implemented on the existed network service, which has a cellular structure. Still, multilateration is limited in cellular structure because it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. This low hearability in the receiver is caused by co-channel interference and multipath environment. Therefore, hearability enhancement is necessary for multilateration under multipath and interference environment. Former time domain based hearability methods were designed for real signals. However, orthogonal frequency division multiplexing (OFDM) signal, which its usage has been increased in digital wireless communication, is a complex signal. Thus, different hearability enhancement method is needed for OFDM signals. This paper proposes a hearability enhancement method for forward-link multilateration using OFDM signals, which employ interference cancellation and multipath mitigation. A novel interference cancellation and multipath mitigation strategy for complex-valued OFDM signals is presented that has an iterative structure. Simulation results show that the proposed multilateration method provides the user's position with an accuracy of less than 80m through the mobile WiMAX cellular network in multipath environment.

• Composites Research
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• 제16권1호
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• pp.13-18
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• 2003

복합재료의 피로수명을 평가하는 것은 여러 가지 파손모드와 파손모드 간의 강호작용 때문에 복잡하다. 본 논문에서는 현상론적인 모델(비선형 강도저하 모델)을 이용하여 피로수명과 잔류강도를 예측할 수 있는 방법을 제시하였다. 잔류강도를 하중 사이클 수와 피로응력의 함수로 가정하였으며, 계산에 필요한 모델변수(강도저하 파라미터, 피로수명형상 파라미터)를 피로수명의 함수로 가정하였다 임의로 배열된 하중 스펙트럼 상에서 응력수준에 따른 모델 매개변수를 구하기 위해 S-N 선도를 이용하였고, 상이한 응력비에 대하여 전술한 매개변수를 Goodman식의 보정을 통하여 계산하였다(피로선도). 임의의 하중이력 후의 잔여강도 분포를 2모수 weibull 함수로 표현하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2859-2872
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• 2019

Interference alignment (IA) has been a powerful approach to achieve the maximum degree of freedom (DoF) for K users multiple-input-multiple-output (MIMO) interference channels. However, due to the feasibility constraint, aligning all the interference signals at each receiver is impractical for large K without symbol extension. In this paper, we propose two best-effort interference alignment (BEIA) schemes that the network selects the maximum number of interfering transmitters to align their signals given the feasibility conditions when each transmitter-receiver pair has a constant number of data streams. Besides, in case of not all interfering signals aligned at each receiver, an upper bound of the average throughput is derived. Simulation results show that the proposed schemes have superiority over the traditional methods, such as time division multiple access (TDMA) and cluster IA(CIA), in low and moderate signal-to-noise ratio (SNR) region in terms of average user throughput. In addition, the proposed max-min relative interference distance alignment scheme outperforms the proposed scheme of equal interfering transmitters number alignment in terms of both average user throughput and minimum user throughput.