Indonesian Journal of Electrical Engineering and Computer Science
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Role-based Trust Management Model in Multi-domain Environment
Get PDFBased on the in-depth analysis of issues in dRBAC model, which include the lack of commission depth control in distributed environment, the inefficiency of cascading revocation of the authorization roles and the incapability of judging whether the commission violates the principles of RBAC model before it is done, this paper proposed MD-dRBAC Model, designed trust management mechanism for MD-dRBAC Model, which was used to control the access, established the credible authority commission tree and finally proposed the detection algorithm for implicit authorities upgrading to avoid violation of the least privilege principle in RBAC model Extensive security and performance analysis show that the proposed schemes are highly efficient and secure. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.191
Evaluation of the Reference Current Generation Methods for Harmonic Compensation Applications using Instantaneous Reactive Power Theory (IRPT)
Get PDFThis paper presents a critical survey of the reference current generation (RCG) methods for harmonic and reactive power compensation for the electrical distribution systems. A critical review of the p-q method, the d-q(id-iq) method, the p-q-r method, the UPF method and the FBD method are presented for the sake of comparison. In order to mitigate the deficiencies of these existing methods, the modified d-q method, the modified p-q-r method, and the modified p-q method are also presented. The MATLAB simulation of these algorithms is carried out for different grid voltage and load conditions scenarios. It is found that, all these algorithms show similar performance in case of ideal grid voltage scenario. In case of grid voltage unbalance or harmonics, the difference in steady state compensation accuracy among these algorithms is presented. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.167
Coordinated Control of SVC and PSS for Transient Stability Enhancement of Multi-Machine Power System
Get PDFThe coordinated control for SVC and generic/multi-band PSS for power swing damping is presented for the multimachine power system. The background and the mathematical models of the generic PSS, the multi-band PSS and the SVC are presented. The V-I characteristics as well as the dynamic properties of the static var compensator (SVC) are presented. The multi-machine power system is simulated using MATLAB and the effect of PSS and SVC on dynamic response of the system under single-phase fault and three-phase fault are simulated. The simulation results reveal that the coordinated control of the SVC and the generic/multi-band PSS is an effective solution to damp low frequency oscillation for multimachine power system and enhance global stability of the large inter-connected power system. DOI: http://dx.doi.org/10.11591/telkomnika.v11i2.175
Thermal Analysis in Gas Insulated Transmission Lines Using an Improved Finite-Element Model
Get PDFIn this paper, an improved finite element (FE) model is proposed to investigate the temperature distribution in gas insulated transmission lines (GILs). The solution of joule losses in eddy current field analysis is indirectly coupled into fluid and thermal fields. As is different from the traditional methods, the surrounding air of the GIL is involved in the model to avoid constant convective heat transfer coefficient, thus multiple species transport technique is employed to deal with the problem of two fluid types in a single model. In addition, the temperature dependent electrical and thermal properties of the materials are considered. The steady-state and transient thermal analysis of the GIL are performed separately with the improved model. The corresponding temperature distributions are compared with experimental results reported in the literature. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.124
One Method of Cloud Computing Bandwidth Allocation Based on Fairness
Get PDFIn order to solve the bandwidth allocation unfairness problem in the cloud computing network, one method uses fairness congestion control algorithm, access control list (ACL) and traffic policing and traffic shaping in the paper. The method can rationally solve the problem after analyzing the reason of cloud computing bandwidth allocation unfairness. For illustration, one network video conference example was utilized to show the method in solving bandwidth allocation unfairness problem.The experimental results show network bandwidths are fairly allocated, packet loss ratio and latency is obvious improvement. The method deals with non-adaptive UDP and TCP adaptive flow congestion and provides the end-to-end quality of service over the differentiated services networks, and the bandwidth allocation problem based on fairness in the cloud computing network is solved well. DOI: http://dx.doi.org/10.11591/telkomnika.v11i2.205
Parameter Designing for Heave Compensation Hydraulic System Installed in Deepwater
Get PDFThe function diagram of active heave compensation hydraulic system has been given, besides, the mathematics model for the principal hydraulic components of the compensation system has been built, and the input-output relation between components has been made clear. Aimed at compensating work capacity for the system, design and research on parameters as the bearing pressure, the initial state and the maximum flow of hydraulic cylinder, accumulator and other principal components have been made separately, and standardized design has been accomplished in accordance with relevant standards. Furthermore, calculus and verification for the capacity of the hydraulic system in different working stages have been made in order to calculate the pressure lose of the system and provide objective data for the hardware system design of the hydraulic components of the heave compensation system. DOI: http://dx.doi.org/10.11591/telkomnika.v11i1.190
Optimization of an Intelligent Controller for Parallel Autonomous Parking
Get PDFAutonomous parking has become the research focus. Fuzzy controller was ofen used to solve the nonlinear and time-varying problem of the autonomous parking. According to the shortcomings of traditional fuzzy controller, a new ant colony algorithm based on idle ant effect was proposed. Firstly, the fuzzy controller was designed based on the kinematic equations. Then, multi-colony parallel optimization was adopted to improve the data initialization, path construction and pheromone update. The method guaranteed the completeness of the membership function and made the fuzzy parameters with higher precision. Finally, both traditional controller and the designed controller were used for the autonomous parking, the experimental results showed that, comparing with the traditional fuzzy controller, the designed controller can improve the stability problem with less error and faster response speed. DOI: http://dx.doi.org/10.11591/telkomnika.v11i2.140
A Novel Prediction Algorithm of DR Position Error Based on Bayesian Regularization Back-propagation Neural Network
Get PDFIt is difficult to accurately reckon vehicle position for vehicle navigation system (VNS) during GPS outages, a novel prediction algorithm of dead reckon (DR) position error is put forward, which based on Bayesian regularization back-propagation (BRBP) neural network. DR, GPS position data are first de-noised and compared at different stationary wavelet transformation (SWT) decomposition level, and DR position error data are acquired after the SWT coefficients differences are reconstructed. A neural network to mimic position error property is trained with back-propagation algorithm, and the algorithm is improved for improving its generalization by Bayesian regularization theory. During GPS outages, the established prediction algorithm predictes DR position errors, and provides precise position for VNS through DR position error data updating DR position data. The simulation results show the positioning precision of the BRBP algorithm is best among the presented prediction algorithms such as simple DR and adaptive linear network, and a precise mathematical model of navigation sensors isn’t established. DOI: http://dx.doi.org/10.11591/telkomnika.v11i7.285
Framework Design of Power Grid Planning and Design Platform
Get PDFPower grid planning and design platform is an integration power grid planning and design and technical-support platform system,serving in power grid companies at all levels and the planning and design unit multistage users for collaborative planning design, comprehensively supporting planning and design basis data management, major network planning, distribution network planning, project planning, planning achievements management and project review. Based on the experience of power grid planning and power grid information construction, an overall architecture design scheme of power grid planning and design platform is presented in this paper. The paper emphasizes the data platform design, and expounds the characteristics of the design platform, which provides the reference and basis for the power grid planning and design platform construction. DOI : http://dx.doi.org/10.11591/telkomnika.v12i5.511