Proposed Search Scheme Research Articles

Hybrid Social Grouping Algorithm-Perturb and Observe Power Tracking Scheme for Partially Shaded Photovoltaic Array

This research work emphasizes proposing a hybrid social grouping algorithm (SGA) and perturb and observe (P&O) scheme for tracking the global power peak in a partially shaded photovoltaic (PV) array. PV panels getting shaded, even partially, exhibits multiple power peaks, and hence conventional maximum power point tracking (MPPT) algorithms fail in tracking the maximum power peak as it gets deceived by local maxima. Most of the prevailing global search algorithms suffer in performance due to the stochastic search which consumes time even after nearing the global power peak. Therefore, a hybridization of the global search algorithm and the conventional algorithm will be a prudent solution. SGA, a global search algorithm based on individual and group cognizant behaviour, has been hybridized with a well-entrenched P&O algorithm that complements each other in achieving the global power peak swiftly. The hybridized algorithm achieves the global power peak in 0.4 seconds faster than the stand-alone SGA algorithm during complex shading conditions. The proposed scheme has been implemented for an 800 W PV array in a MATLAB simulation and validated experimentally in a hardware setup using a SAS1000L solar array simulator-programmable source, a DC-DC converter, and a dSPACE 1104 controller. The simulation and experimental results reveal that the proposed search scheme is very competent in converging towards the global maximum through SGA first and achieving the peak point through P&O. The proposed scheme has also been tested for a dynamic shading pattern, and it is evident that the proposed scheme outperforms its counterparts in terms of convergence time.

Increasing the accuracy of finding the coordinates of sea mines by means of kinematic design

The issue of demining reservoirs, rivers and sea raids and ports, which is relevant for Europe during the period of active deployment of military confrontations on its territory, is considered. Only in the maritime territorial waters of Ukraine and in the water areas of its freshwater reservoirs and rivers, during the year of the war, the enemy laid up to a thousand different mines. Demining of the Ukrainian water spaces of the sea, reservoirs and rivers is an important social and economic problem, the solution of which does not tolerate delay and waiting for the full end of hostilities.
 The purpose of the work is the development of principle schemes for optimizing the spatial movements of search and mine clearance vessels and the creation of algorithms for calculating the precise coordinates of the spatial location of floating, anchor and bottom mines by means of kinematic design.
 The research methodology was the application of the theory of mapping coordinates and trajectories of spatial movements of moving objects by means of graphic geometry, taking into account the specifics and dynamic features of kinematic design.
 A schematic diagram of the spatial location of search trawlers and UAVs or auxiliary search floats when searching for mines has been developed. Mathematical dependencies have also been established for the precise calculation of the coordinates of detected mines based on the data of the applied theory and kinematic design schemes. For the search for floating mines, the optimal trajectory of search movements of unmanned aerial vehicles along the Archimedean spiral is proposed. The optimal number of aircraft that search for floating mines at the same time has been determined. As one of the most effective options for the disposal of mines, their detonation with warheads dropped from an aerial liquidator drone has been proposed.
 The main result of the study is the creation of a methodology for calculating the refined coordinates of the search for floating, anchor and bottom mines in combination with the optimization of the trajectories of the search movements of aerial and floating search vehicles along the Archimedean spiral. This ensures not only a 25-30% increase in surveyed and demined areas, but also a proportional saving of fuel due to a reduction in the number of crossings of search trawlers. It has been established that at speeds of spatial movements of search aircraft or auxiliary floating means of 5÷5.5 m/s, using the proposed search scheme, it is possible to survey up to 6 square kilometers of sea water area every hour. At the same time, it is possible to save up to a third of the cost of expensive fuel due to the reduction of movements of the trawler boat.

Increasing the accuracy of finding the coordinates of sea mines by means of kinematic design

The issue of demining reservoirs, rivers and sea raids and ports, which is relevant for Europe during the period of active deployment of military confrontations on its territory, is considered. Only in the maritime territorial waters of Ukraine and in the water areas of its freshwater reservoirs and rivers, during the year of the war, the enemy laid up to a thousand different mines. Demining of the Ukrainian water spaces of the sea, reservoirs and rivers is an important social and economic problem, the solution of which does not tolerate delay and waiting for the full end of hostilities. The purpose of the work is the development of principle schemes for optimizing the spatial movements of search and mine clearance vessels and the creation of algorithms for calculating the precise coordinates of the spatial location of floating, anchor and bottom mines by means of kinematic design. The research methodology was the application of the theory of mapping coordinates and trajectories of spatial movements of moving objects by means of graphic geometry, taking into account the specifics and dynamic features of kinematic design. A schematic diagram of the spatial location of search trawlers and UAVs or auxiliary search floats when searching for mines has been developed. Mathematical dependencies have also been established for the precise calculation of the coordinates of detected mines based on the data of the applied theory and kinematic design schemes. For the search for floating mines, the optimal trajectory of search movements of unmanned aerial vehicles along the Archimedean spiral is proposed. The optimal number of aircraft that search for floating mines at the same time has been determined. As one of the most effective options for the disposal of mines, their detonation with warheads dropped from an aerial liquidator drone has been proposed. The main result of the study is the creation of a methodology for calculating the refined coordinates of the search for floating, anchor and bottom mines in combination with the optimization of the trajectories of the search movements of aerial and floating search vehicles along the Archimedean spiral. This ensures not only a 25–30 % increase in surveyed and demined areas, but also a proportional saving of fuel due to a reduction in the number of crossings of search trawlers. It has been established that at speeds of spatial movements of search aircraft or auxiliary floating means of 5÷5.5 m/s, using the proposed search scheme, it is possible to survey up to 6 square kilometers of sea water area every hour. At the same time, it is possible to save up to a third of the cost of expensive fuel due to the reduction of movements of the trawler boat.

Efficient Joint-Dimensional Search with Solution Space Regularization for Real-Time Semantic Segmentation

Semantic segmentation is a popular research topic in computer vision, and many efforts have been made on it with impressive results. In this paper, we intend to search an optimal network structure that can run in real-time for this problem. Towards this goal, we jointly search the depth, channel, dilation rate and feature spatial resolution, which results in a search space consisting of about \(2.78\times 10^{324}\) possible choices. To handle such a large search space, we leverage differential architecture search methods. However, the architecture parameters searched using existing differential methods need to be discretized, which causes the discretization gap between the architecture parameters found by the differential methods and their discretized version as the final solution for the architecture search. Hence, we relieve the problem of discretization gap from the innovative perspective of solution space regularization. Specifically, a novel Solution Space Regularization (SSR) loss is first proposed to effectively encourage the supernet to converge to its discrete one. Then, a new Hierarchical and Progressive Solution Space Shrinking method is presented to further achieve high efficiency of searching. In addition, we theoretically show that the optimization of SSR loss is equivalent to the \(L_{0}\)-norm regularization, which accounts for the improved search-evaluation gap. Comprehensive experiments show that the proposed search scheme can efficiently find an optimal network structure that yields an extremely fast speed (175 FPS) of segmentation with a small model size (1 M) while maintaining comparable accuracy.

Blockchain-Based Employment Contract System Architecture Allowing Encrypted Keyword Searches

We introduce a blockchain-based online employment contract system to protect the rights and interests of both employees and employers. In the proposed model, an employer and a worker can interactively create a new electronic online contract, and the mutually signed contract is saved on a contract blockchain so that the contract becomes certifiable but cannot be forged by the contract signers. In particular, the blockchain in our system provides transactional privacy to protect sensitive personal information such as social identifier, contact information, income, and so forth, contained in the contract. Since a remote cloud server must provide not only secure storage, accessibility, and availability of all signed contracts, but also increased security in the server, we propose a new encrypted keyword search mechanism with enhanced search accuracy. Each contract is associated with encrypted keywords generated from the names of contractual parties and must remain confidential and anonymous even to the server. Although, the contracts must always be accessible by the contract signers, only the cloud server should be able to retrieve each user’s contract without decrypting the contract or identifying the contract signer. To meet these requirements, we propose a new encrypted keyword search mechanism based on Gentry’s homomorphic encryption technology; the server can find each user’s contract when two encrypted arbitrary keywords are homomorphic to each other. Since the keywords in the proposed system are based on person names or business names, they are easily predictable, and, thereby, many synonyms for a keyword can exist. Therefore, the proposed encrypted keyword search takes into account not only the keywords but also the ownership of each contract; in this way, the proposed search scheme is secure against a keyword guessing attack and provides strong search accuracy against the keyword synonyms. As a result, users can only access their own contracts, and the cloud server can exactly retrieve the requester’s contracts. Implementations for the proposed system and corresponding analysis on its security and simulated performance are provided.

On Detection of Narrow Angle <formula formulatype="inline"><tex Notation="TeX">${\rm e}\!+\!{\rm e}- $</tex> </formula> Pairs From Dark Photon Decays

A class of models of dark sectors consider new very weak interaction between the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark photons) mixing with our photons. If such A's exist, they could be searched for in a light-shining-through-a-wall experiment with a high energy electron beam from the CERN SPS. The proposed search scheme suggests detection of the e+e- pairs produced in the A' -> e+e- decay with a very small opening angle. Coordinate chambers based on the thin-wall drift tubes with a minimal material budget and a two-hit resolution for e+ and e- tracks separated by more than 0.5 mm are considered as an option for detecting such pairs.

Classification-based learning by particle swarm optimization for wall-following robot navigation

In this paper, we study the parameter setting for a set of intelligent multi-category classifiers in wall-following robot navigation. Based on the swarm optimization theory, a particle selecting approach is proposed to search for the optimal parameters, a key property of this set of multi-category classifiers. By utilizing the particle swarm search, it is able to obtain higher classification accuracy with significant savings on the training time compared to the conventional grid search. For wall-following robot navigation, the best accuracy (98.8%) is achieved by the particle swarm search with only 1/4 of the training time by the grid search. Through communicating the social information available in particle swarms in the training process, classification-based learning can achieve higher classification accuracy without prematurity. One of such learning classifiers has been implemented in SIAT mobile robot. Experimental results validate the proposed search scheme for optimal parameter settings.

The Localization Method of Active Olfaction Robot and Experimental Study

An active olfaction implementation scheme based on zigzag search algorithm using a wheeled mobile robot and the experimental verification are put forward. Firstly, the hardware structure of the active olfaction robot is setup. Secondly, the Zigzag-based robot active olfaction dynamic system implementation procedure in the simulated environment is presented, including plume finding, plume tracking and odor source declaration, and simulation results validate the proposed search scheme. The entire system was used under steady wind condition to locate the ethanol odor source. Choice 15m as the start distance, and after 10 times locating, the error is less than 5% and the experimental results prove that the system recognition is accuracy.

채널 유휴 확률 추정을 이용한 인지 라디오 시스템의 유휴채널 탐색 기법

본 논문에서는 다중 채널이 존재하는 인지 라디오 시스템에서 다중 사용자가 협력하여 유휴 채널 탐색 시간을 줄이는 방법을 제안한다. 구체적으로 채널 상태에 대한 마르코프 모델을 토대로 각 채널의 유휴 확률을 추정하고 확률이 높은 순서대로 채널을 센싱함으로써 유휴 채널 탐색 시간을 줄이는 방법을 제안한다. 또한 제안한 탐색 방법을 사용자 그룹을 형성하여 그룹마다 서로 다론 채널을 동시에 센싱하는 방법과 결합함으로써 보다 향상된 센싱 성능을 얻을 수 있도록 한다. 모의실험을 통해 사용자 그룹을 형성하는 방법은 검출 신뢰도를 저하시키지만 탐색시간을 감소시킴을 검증하고, 채널 유휴 확률 추정을 이용한 센싱 순서 결정 방법을 사용하여 임의 탐색 기법에 비해 상당한 탐색 시간 감소 효과를 얻을 수 있음을 검증하였다. 최종적으로 제안한 채널 유휴 확률 추정 기반 탐색 방법과 사용자 그룹 형성 기법을 모두 적용한 인지 라디오 시스템의 유휴 채널 탐색 성능을 검증하였다. In this paper, idle channel search schemes based on spectrum sensing are proposed for cognitive radio systems with multiple channels. Specifically, we propose a scheme for determining the order of sensing for multiple channels, for which the probability of each channel being idle is estimated every search interval. By performing sensing in the descending order of the probabilities, the time required for searching idle channels is expected to decrease. In addition, we combine the proposed scheme with a user grouping scheme to further improve the sensing performance. Simulation results show that the user grouping reduces the search time, although it degrades the reliability of detection. The proposed search scheme based on probability estimation of channel idleness is found to reduce the search time significantly as compared to the conventional random search scheme. We apply both the proposed search scheme and user grouping scheme to a cognitive radio system to validate the overall performance.

자기 조직적 우수 피어 링 구조를 이용한 피어-투-피어 검색기법

본 논문에서는 비구조적 피어-투-피어 시스템에서의 낮은 검색 성공률과 긴 검색 시간을 개선하기 위하여, 성능이 우수한 우수 피어들로 자기 조직적인 링 구조를 구성하고 광고 및 검색에 이용하는 검색 기법을 제안하였다. 우수 피어 링 구조는 동적인 환경에서 시스템의 상황에 따라 적응적으로 크기가 변하고, 에이전트를 이용하여 지속적으로 우수한 피어들이 링 구조에 참여하게 함으로써 성공률을 높이고, 빠른 검색 시간을 유지할 수 있게 하였다. We propose a peer-to-peer search scheme in which super peers with high rapacity constitute a ring by themselves and all peers utilize the ring for their query and publishing keys. In a dynamic peer-to-peer environment, the size of the super peer ring changes adaptively according to the changes of the system, but more powerful peers are continuously promoted to super peers. By simulations, we show that our proposed search scheme improves the query success rate of Gnutella+1hop replication search method, and maintains shorter query delay than JXTA as a static ring.

Three-phase load balancing in distribution systems using index measurement technique

By changing open/closed status of sectionalizing and tie-switches, the topological structure of distribution feeders is altered for network reconfiguration in power system. Network reconfiguration can be applied to balance feeder loads and ease overload conditions in a network by transferring loads from the heavily loaded feeders to the lightly loaded ones. In this paper an attempt is made to enhance three-phase load balancing by introducing new indices for load balancing. The loading condition of the branches and the overall system are determined using the proposed indices and the index values have to be minimum for optimum load balancing. For optimal load balancing condition, the branch load-balancing indices will be nearly equal to each other, and also closely approximate to the overall system load-balancing index. In the proposed index measurement technique (IMT), network reconfiguration for load balancing is done by performing a search over different radial configurations created by considering branch-exchange type switches. In the initial stage of the proposed technique, a loop-index is employed to determine a loop, which gives maximum improvement in load balancing in the network. In the final stage, a branch-exchange index is applied to determine the switching-option in that loop to achieve maximum enhancement in load balancing. By using the proposed search scheme, the most appropriate switching-operations for load balancing can be identified. The algorithm has been tested on a 69-bus radial distribution system and the test results indicate that the optimal or near optimal configuration for load balancing can be obtained by the proposed technique with less computational effort and time. A comparative study is made with the two of the established methods and the proposed method is found to be better. The numerous load-flow runs have been drastically reduced in the proposed method. The proposed method will be a most useful tool for real-time control of automated distribution system for load balancing.

Optimization of pipe networks including pumps by simulated annealing

The objective of this work is to present an application of the simulated annealing method for the optimal design of pipe networks including pumps. Although its importance, the optimization of pumped networks did not receive great attention in the literature. The proposed search scheme explores the discrete space of the decision variables: pipe diameters and pump sizes. The behavior of the pumps is describe through the characteristic curve, generating more realistic solutions. In order to demonstrate the versatility of the approach, three different examples of optimal design problems are solved.