Hasil Pencarian  ::  Simpan CSV :: Kembali

"Time synchronization is a vital process in wireless sensor networks, where energy sources are highly limited. In this work, we propose a broadcast-based skew correction technique that will improve both the accuracy and the lifetime of any time synchronization protocol that only corrects time offsets among sensor nodes. Using time information transmitted periodically by the root node, each client node can compensate its software clock frequency in real time after an initial offset correction. The experimental results show that a clock skew below 0.05 us/s can be consistently achieved with appropriate compensation parameters after the correction process is stabilized."

"In recent times, thedemand for the real time audio and video applications in wireless networks isvery high due to widespread use of latest wireless communication technologies.Many of these applications require different Quality of Service (QoS) in termsof delay and throughput in the resource constrained wireless networks. In orderto handle the resources effectively and to increase the QoS, proper packetscheduling algorithms need to be developed. Low-latency Queuing (LLQ) is a packet scheduling algorithm whichcombines Strict Priority Queuing(SPQ) to Class-Based Weighted Fair Queuing (CB-WFQ). LLQ places delay sensitive applications suchas voice and video in the SPQ and treat them preferentially over other trafficby allowing the application to be processed and sent first from the SPQ. In this paper, an Enhanced LLQ (ELLQ) is proposed.An additional SPQ is introduced for scheduling the video applicationsseparately along with the dedicated SPQ for voice applications. The performanceof the proposed algorithm is compared with other existing algorithms throughsimulations using the OPNET modeler. Simulation and Statistical results showthat the proposed algorithm has given 1.5 times performance improvement interms of throughput and delay than the existing algorithms for the real timeaudio and video applications."

"The low-cost WirelessSensor Network(WSN) consists of small battery powered devices called sensors, with limitedenergy capacity. Once deployed, accessibility to any sensor node for maintenance and battery replacement is not feasibledue to the spatial scattering of the nodes. This will lead to an unreliable,limited lifetime and a poor connectivity network. In this paper a novel bio-inspired cluster-baseddeployment algorithm is proposed for energy optimization of the WSNand ultimately to improve the network lifetime. In the cluster initializationphase, a singlecluster is formed with a single cluster head at the center of the sensing terrain. Thesecond phase is for optimum cluster formation surroundingthe inner cluster, based on swarming bees and a piping technique. Each cluster member distributesits data to its corresponding cluster head and the cluster head communicateswith the base station, which reduces the communication distance of each node. The simulationresults show that, whencompared with other clustering algorithms, the proposed algorithm can significantly reducethe number of clusters by 38% and improve the network lifetime by a factor of1/4."

"ABSTRAKPerkembangan teknologi dan transformasi sosial-ekonomi telah menyebabkan bisnis jaringan seluler 5G mengalami perubahan, sehingga jaringan seluler 5G diharapkan dapat mengirim informasi dengan cepat dan mendukung kasus penggunaan yang banyak bermunculan dari berbagai aplikasi. Salah satu kasus penggunaan pada jaringan 5G adalah massive Machine Type Communication (MTC). Salah satu aplikasi massive MTC adalah jaringan sensor nirkabel (JSN). Tantangan bagi jaringan seluler 5G ini adalah bagaimana memodelkan arsitektur/topologi untuk mendukung JSN dan bagaimana mengatasi masalah efisiensi konsumsi energi di JSN. Untuk menjawab tantangan ini, maka diterapkan sistem HAP yang terintegrasi JSN dan menggunakan protokol routing Low Energy Adaptive Clustering Hierarchy. Sistem HAP dirancang untuk digunakan di ketinggian 20 km dengan topologi tanpa dan dengan clustering, menggunakan 1.000 node sensor. Sistem ini telah disimulasikan dengan menggunakan MATLAB. Simulasi dilakukan untuk melihat konsumsi energi, jumlah node yang mati dan rata-rata total paket yang dikirim ke HAP untuk topologi tanpa dan dengan clustering. Dari serangkaian simulasi, terlihat bahwa topologi dengan clustering dapat mengurangi konsumsi energi dan jumlah node yang mati, sekaligus meningkatkan total paket yang dikirimkan ke HAP."

"Penerapan sistem transfer daya nirkabel didalam kehidupan sehari –hari kini semakin berkembang. Kebutuhan sistem transfer daya nirkabel yang mampu digunakan secara praktis serta mampu melayani beban arus searah ( DC ) untuk daya rendah seperti charging handphone, menjadikan sistem ini terus dikembangkan. Sehingga perancangan sistem transfer daya nirkabel dilakukan untuk memperoleh efisiensi yang baik serta handal. Rancangan Colpiitts Osilator yang dipadukan dengan flat spiral coil pada sistem transmitter digunakan untuk memperoleh efisiensi daya, kestabilan frekuensi dan amplitudo tegangan osilasi sehingga diperoleh jarak penghantaran listrik yang diinginkan dalam dimensi yang kecil serta rangkaian yang sederhana namun tetap handal dalam transfer daya ke beban arus searah ( DC ) di receiver. Untuk itu, pada penelitian ini dilakukan perancangan sistem transfer daya nirkabel yang bekerja pada frekuensi 333,1 KHz dengan efisiensi daya transfer sebesar 53.29 % pada jarak efektif 3 mm untuk dapat melayani beban arus searah ( DC ) berupa lampu 12V/5Watt.

---

The application of wireless power transfer systems in daily life is now growing. The need for a wireless power transfer system that can be used practically and able to serve low power direct current (DC) load such as charging mobile phones, making this system continues to be developed. So that design wireless power transfer system is being done to obtain good efficiency and reliable. Design Colpitts oscillator combined with a flat spiral coil in the transmitter system used to obtain power efficiency, stability of oscillation frequency and amplitude of voltage in order to obtain the desired electrical transfer distances in small dimensions and simple circuit but reliable in the power transfer to the DC load on the receiver . Therefore, in this study conducted design wireless power transfer system that worked at a frequency of 333,1 KHz with efficiency system of 53.29% at a distance of 3 mm effectively and able to direct current ( DC ) load in the form of a light 12V/5Watt."

"Besarnya potensi akan penerapan transfer daya tanpa kabel pada kehidupan nyata membuat sistem Wireless Power Transfer(WPT) menjadi sorotan penelitian di banyak negara. Salah satu aplikasi dari teknologi ini yang sedang populer dan terus dikembangkan ialah wireless charger (pengisi baterai tanpa kabel). Untuk aplikasi ini, dimensi menjadi sebuah faktor penting untuk dipertimbangkan, sehingga sistem WPT dengan dimensi yang sesuai perlu dikembangkan. Sementara itu, komponen yang paling memperngaruhi besarnya dimensi perangkat dalam sistem ini ialah rangkaian osilator dalam rangkaian pemancar/transmitter. Pada penelitian ini, penulis merancang sebuah rangkaian osilator sederhana, osilator Flyback dengan dimensi 8 x 10 cm. Rangkaian flyback ini pada dasarnya adalah sebuah driver, namun karena kesederhanaan rangkaiannya, penulis menggunakannya sebagai rangkaian osilator pada sistem WPT. Sistem yang penulis rancang bekerja pada frekuensi 700 kHz dengan efisiensi sistem 7.43% pada jarak 11 cm. Sementara efisiensi osilator ialah 15.01% pada frekuensi 7.35 kHz.

---

The great potential of Wireless Power Transfer system implementations to the real world has attracted many researchers‟ attention worldwide. One of its popular application is wireless charger. For this application, dimension becomes an important factor to be considered. So, a WPT System with reasonable dimension is required. Meanwhile, the component that dominate the dimension of the system is the oscillator circuit of the transmitter.

In this research, the author proposed a simple oscillator circuit, flyback circuit with the 8 x 10 cm PCB dimension. This circuit is basically a driver circuit, but because of its simplicity, the author used it as an oscillator. The system works in 700 kHz of frequency with an efficiency of 7.43% at 11 cm (distance of transmitter and receiver antenna). And the efficiency of the oscillator its self is 15.01% at 7.35 kHz frequency."

"This book provides an overview of the latest research and development of new technologies for cognitive radio, mobile communications, and wireless networks. The contributors discuss the research and requirement analysis and initial standardization work towards 5G cellular systems and the capacity problems it presents. They show how cognitive radio, with the capability to flexibly adapt its parameters, has been proposed as the enabling technology for unlicensed secondary users to dynamically access the licensed spectrum owned by legacy primary users on a negotiated or an opportunistic basis. They go on to show how cognitive radio is now perceived in a much broader paradigm that will contribute to solve the resource allocation problem that 5G requirements raise. The chapters represent hand-selected expanded papers from EAI sponsored and hosted conferences such as the 12th EAI International Conference on Mobile and Ubiquitous Systems, the 11th EAI International Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness, the 10th International Conference on Cognitive Radio Oriented Wireless Networks, the 8th International Conference on Mobile Multimedia Communications, and the EAI International Conference on Software Defined Wireless Networks and Cognitive Technologies for IoT."

"This book presents peer-reviewed contributions from the 5th International Conference on Mobile and Wireless Technology (ICMWT 2018), held June 25-27, 2018 in Hong Kong. This conference provided researchers and practitioners from both academia and industry with a platform to keep them abreast of cutting-edge developments in the field. The book includes papers on mobile and wireless networks and their applications, the increasingly important security issues relating to mobile and wireless systems, data management, as well as the latest developments in mobile software development, and multimedia and wireless communications."