• Title/Summary/Keyword: Channel optimization

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Development of Classification Model for hERG Ion Channel Inhibitors Using SVM Method (SVM 방법을 이용한 hERG 이온 채널 저해제 예측모델 개발)

  • Gang, Sin-Moon;Kim, Han-Jo;Oh, Won-Seok;Kim, Sun-Young;No, Kyoung-Tai;Nam, Ky-Youb
    • Journal of the Korean Chemical Society
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    • v.53 no.6
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    • pp.653-662
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    • 2009
  • Developing effective tools for predicting absorption, distribution, metabolism, excretion properties and toxicity (ADME/T) of new chemical entities in the early stage of drug design is one of the most important tasks in drug discovery and development today. As one of these attempts, support vector machines (SVM) has recently been exploited for the prediction of ADME/T related properties. However, two problems in SVM modeling, i.e. feature selection and parameters setting, are still far from solved. The two problems have been shown to be crucial to the efficiency and accuracy of SVM classification. In particular, the feature selection and optimal SVM parameters setting influence each other, which indicates that they should be dealt with simultaneously. In this account, we present an integrated practical solution, in which genetic-based algorithm (GA) is used for feature selection and grid search (GS) method for parameters optimization. hERG ion-channel inhibitor classification models of ADME/T related properties has been built for assessing and testing the proposed GA-GS-SVM. We generated 6 different models that are 3 different single models and 3 different ensemble models using training set - 1891 compounds and validated with external test set - 175 compounds. We compared single model with ensemble model to solve data imbalance problems. It was able to improve accuracy of prediction to use ensemble model.

A Study on Flow Distribution to Flocculation Basins Using DOE and RSA (실험계획법과 반응표면분석법을 적용한 응집지로의 유량분배에 관한 연구)

  • Kim, Seong-Jae;Kyung, Gyu-Sun;Jeong, Heui-Jung;Kim, Hyeong-Seop;Yang, Sa-Sun
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.12
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    • pp.918-928
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    • 2013
  • The inequitable flow distribution to flocculation basins is an important problem faced in many water treatment plants. This is caused by the structure of a distribution channel, the height differences of outlet weirs etc. But, a modified approach for the structures has no effectiveness to achieve flow equality. The aim of this study is to reduce the inequality by adopting optimized inlet valve opening (%) of the flocculation basins using DOE (Design of Experiments) and RSA (Response Surface Analysis). The inlet valve openings (%) and inflow distributions (%) of 6 paralleled basins were set as factors (X) and characteristics(Y) respectively. 2 level factorial experiments and RSA were conducted for optimization and regression analysis (Y = f(X) + Const.). Adopting the optimized inlet valve opening (%) at field, standard deviation of flow distribution (%) and effluent turbidity was declined from 3.80% to 0.42% and from 0.29 NTU to 0.03 NTU respectively.

Application of exponential bandwidth harmony search with centralized global search for advanced nonlinear Muskingum model incorporating lateral flow (Advanced nonlinear Muskingum model incorporating lateral flow를 위한 exponential bandwidth harmony search with centralized global search의 적용)

  • Kim, Young Nam;Lee, Eui Hoon
    • Journal of Korea Water Resources Association
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    • v.53 no.8
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    • pp.597-604
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    • 2020
  • Muskingum, a hydrologic channel flood routing, is a method of predicting outflow by using the relationship between inflow, outflow, and storage. As many studies for Muskingum model were suggested, parameters were gradually increased and the calculation process was complicated by many parameters. To solve this problem, an optimization algorithm was applied to the parameter estimation of Muskingum model. This study applied the Advanced Nonlinear Muskingum Model considering continuous flow (ANLMM-L) to Wilson flood data and Sutculer flood data and compared results of the Linear Nonsingum Model incorporating Lateral flow (LMM-L), and Kinematic Wave Model (KWM). The Sum of Squares (SSQ) was used as an index for comparing simulated and observed results. Exponential Bandwidth Harmony Search with Centralized Global Search (EBHS-CGS) was applied to the parameter estimation of ANLMM-L. In Wilson flood data, ANLMM-L showed more accurate results than LMM-L. In the Sutculer flood data, ANLMM-L showed better results than KWM, but SSQ was larger than in the case of Wilson flood data because the flow rate of Sutculer flood data is large. EBHS-CGS could be appplied to be appplicable to various water resources engineering problems as well as Muskingum flood routing in this study.

DNN-Based Dynamic Cell Selection and Transmit Power Allocation Scheme for Energy Efficiency Heterogeneous Mobile Communication Networks (이기종 이동통신 네트워크에서 에너지 효율화를 위한 DNN 기반 동적 셀 선택과 송신 전력 할당 기법)

  • Kim, Donghyeon;Lee, In-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.10
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    • pp.1517-1524
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    • 2022
  • In this paper, we consider a heterogeneous network (HetNet) consisting of one macro base station and multiple small base stations, and assume the coordinated multi-point transmission between the base stations. In addition, we assume that the channel between the base station and the user consists of path loss and Rayleigh fading. Under these assumptions, we present the energy efficiency (EE) achievable by the user for a given base station and we formulate an optimization problem of dynamic cell selection and transmit power allocation to maximize the total EE of the HetNet. In this paper, we propose an unsupervised deep learning method to solve the optimization problem. The proposed deep learning-based scheme can provide high EE while having low complexity compared to the conventional iterative convergence methods. Through the simulation, we show that the proposed dynamic cell selection scheme provides higher EE performance than the maximum signal-to-interference-plus-noise ratio scheme and the Lagrangian dual decomposition scheme, and the proposed transmit power allocation scheme provides the similar performance to the trust region interior point method which can achieve the maximum EE.

Efficient Interference Alignment for Uplink MIMO/FDD Systems with Limited Feedback (제한된 궤환 채널 기반 상향링크 MIMO/FDD 시스템에서의 효율적인 간섭 정렬 기법)

  • Cho, Sung-Yoon;Jang, Jin-Young;Kim, Dong-Ku
    • Journal of Advanced Navigation Technology
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    • v.16 no.6
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    • pp.988-996
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    • 2012
  • Assuming perfect channel state information (CSI), the conventional interference alignment (IA) algorithm in the uplink cellular system suppresses inter-cell interference (ICI) by aligning ICI to a randomly selected reference vector. However, IA in practice relies on limited feedback between base stations and users, resulting in residual ICI. In this paper, we propose the optimization of the reference vector that minimizes the upper-bound of residual ICI power. Secondly, the iterative IA that designs the direction of transmit and receive filter is proposed to minimize the residual ICI as well as maximize the desired signals. Moreover, we propose the user scheduling method combined with proposed IA schemes which provides the multiuser diversity gain in multi-cell environments. Finally, the performance gain of the proposed IA algorithms compared with the existing IA are analyzed and demonstrated by simulation results.

Design Optimization of a Type-I Heterojunction Tunneling Field-Effect Transistor (I-HTFET) for High Performance Logic Technology

  • Cho, Seong-Jae;Sun, Min-Chul;Kim, Ga-Ram;Kamins, Theodore I.;Park, Byung-Gook;Harris, James S. Jr.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.11 no.3
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    • pp.182-189
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    • 2011
  • In this work, a tunneling field-effect transistor (TFET) based on heterojunctions of compound and Group IV semiconductors is introduced and simulated. TFETs based on either silicon or compound semiconductors have been intensively researched due to their merits of robustness against short channel effects (SCEs) and excellent subthreshold swing (SS) characteristics. However, silicon TFETs have the drawback of low on-current and compound ones are difficult to integrate with silicon CMOS circuits. In order to combine the high tunneling efficiency of narrow bandgap material TFETs and the high mobility of III-V TFETs, a Type-I heterojunction tunneling field-effect transistor (I-HTFET) adopting GeAlxGa1xAsGe system has been optimized by simulation in terms of aluminum (Al) composition. To maximize device performance, we considered a nanowire structure, and it was shown that high performance (HP) logic technology can be achieved by the proposed device. The optimum Al composition turned out to be around 20% (x=0.2).

A Study on the Imprinting Process for an Optical Interconnection of PLC Device (광소자의 광 정렬 및 연결 구조 구현용 임프린트 공정 연구)

  • Kim, Young Sub;Cho, Sang Uk;Kang, Ho Ju;Jeong, Myung Yung
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.12
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    • pp.1376-1381
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    • 2012
  • Optical devices are used extensively in the field of information network. Increasing demand for optical device, optical interconnection has been a important issue for commercialization. However many problems exist in the interconnection between optical device and optical fiber, and in the case of the multi-channel, problems of the optical alignment and optical array arise. For solving the alignment and array problem of optical device and the optical fiber, we fabricated fiber alignment and array by using imprint technology. Achieved higher precision of optical fiber alignment and array due to fabricating using imprint technology. The silicon stamp with different depth was fabricated using the conventional photolithography. Using the silicon stamp, a nickel stamp was fabricated by electroforming process. We conducted imprint process using the nickel stamp with different depth. The optical alignment and array by fabricating the patterns of optical device and fiber alignment and array using imprint process, and achieved higher precision of decreasing the dimensional error of the patterns by optimization of process. The fabricated optical interconnection of PLC device was measured 3.9 dB and 4.2 dB, lower than criteria specified by international standard.

Call Admission Control Techniques of Mobile Communication System using SRN Models (SRN 모델을 이용한 이동통신 시스템의 호 수락 제어 기법)

  • 로철우
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.12
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    • pp.529-538
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    • 2002
  • Conventional method to reduce the handoff call blocking probability(PBH) in mobile communication system is to reserve a predetermined number of channels only for handoff calls. To determine the number of reserved channels, an optimization problem, which is generally computationally heavily involved, must be solved. In this Paper, we propose a call admission control (CAC) scheme that can be used to reduce the PBH without reserving channels in advance. For this, we define a new measure, gain, which depends on the state of the system upon the arrival of a new call. The proposed CAC decision rule relies on the gain computed when a new call arrives. SRN, an extended stochastic Petri nets, provides compact modeling facilities for system analysis can be calculated performance index by appropriate reward to the model. In this Paper, we develop SRN models which can perform the CAC with gain. The SRN models are 2 level hierarchical models. The upper layer models are the structure state model representing the CAC and channel allocation methods considering QoS with multimedia traffic The lower layer model Is to compute the gain under the state of the upper layer models.

Spectrum Allocation and Service Control for Energy Saving Based on Large-Scale User Behavior Constraints in Heterogeneous Networks

  • Yang, Kun;Zhang, Xing;Wang, Shuo;Wang, Lin;Wang, Wenbo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.8
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    • pp.3529-3550
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    • 2016
  • In heterogeneous networks (HetNets), energy saving is vital for a sustainable network development. Many techniques, such as spectrum allocation, network planning, etc., are used to improve the network energy efficiency (EE). In this paper, micro BSs utilizing cell range expansion (CRE) and spectrum allocation are considered in multi-channel heterogeneous networks to improve EE. Hotspot region is assumed to be covered by micro BSs which can ensure that the hotspot capacity is greater than the average demand of hotspot users. The expressions of network energy efficiency are derived under shared, orthogonal and hybrid subchannel allocation schemes, respectively. Particle swarm optimization (PSO) algorithm is used to solve the optimal ratio of subchannel allocation in orthogonal and hybrid schemes. Based on the results of the optimal analysis, we propose three service control strategies on the basis of large-scale user behaviors, i.e., adjust micro cell rang expansion (AmCRE), adjust micro BSs density (AmBD) and adjust micro BSs transmit power (AmBTP). Both theoretical and simulation results show that using shared subchannel allocation scheme in AmBD strategies can obtain maximal EE with a very small area ratio. Using orthogonal subchannel allocation scheme in AmCRE strategies can obtain maximal EE when area ratio is larger. Using hybrid subchannel allocation scheme in AmCRE strategies can obtain maximal EE when area ratio is large enough. No matter which service control strategy is used, orthogonal spectrum scheme can obtain the maximal hotspot user rates.

Optimizing the Configurations of Cooling Channels with Low Flow Resistance and Thermal Resistance (냉각유로 형상변화에 따른 유동 및 열저항 최적화 연구)

  • Cho, Kee-Hyeon;Ahn, Ho-Seon;Kim, Moo-Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.1
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    • pp.9-15
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    • 2011
  • In this study, we investigated the hydrodynamic and thermal performance of constructal architectures on the basis of the mass flow rates for a given pressure drop, and we determined the thermal resistance and flow uniformity. The five flow configuration used in this study were the first construct with optimized hydraulic diameter, the second construct with optimized hydraulic diameter, the first construct with non-optimized hydraulic diameter, second construct with non-optimized hydraulic diameter, and a serpentine configuration. The results of our study suggest that the best fluid-flow structure is the second constructal structure with optimized constructal configurations. We also found that in the case of the optimized structure of cooling plates, the heat transfer was remarkably higher and the pumping power was significantly lower than those of traditional channels.