94 research outputs found
Indoor Wireless Communications using Slotted ISMA protocols
No full textThe performance of the Slotted ISMA protocols in Rician fading channel for Indoor Wireless communications considering Pico Cellular systems have been analyzed in this thesis. The throughput of Slotted nonpersistant Inhibit Sense Multiple Access (np-ISMA), Slotted 1-persistent ISMA (1p-ISMA) and Slotted np-ISMA\CD (Collision Detection) is investigated in the presence of n-interfering signals whose random amplitudes are considered as Rician distributed. Numerical results are presented, indicating the effect of propagation impairments on channel capacity. The results are of importance for mobile networks and indoor wireless office communications.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Unslotted Hybrid CDMA/ISMA Protocol for Indoor Wireless Computer Communications
No full textA hybrid Code Division Multiple Access / Inhibit Sense Multiple Access (CDMA/ISMA) protocol has been proposed as an effective multiple access scheme for Indoor Wireless Computer Communications. This new protocol combines the advantages of both CDMA and ISMA into one protocol. On the one hand the ISMA protocol introduces a limitation to the number of simultaneous accesses to the transmission channel. On the other hand the CDMA protocol introduces an improvement to the packet survival chance. It is shown that the performance of the hybrid protocol is indeed better than CDMA only. In addition, code sharing can be applied to reduce hardware cost. The slotted hybrid CDMA/ISMA protocol using the p-persistent ISMA scheme has already been analysed. In this report, we investigate the hybrid protocol using the unslotted non-persistent ISMA scheme. The analysis is done for a star-connected multiple access wireless computer network. The performance comparison between the slotted and unslotted hybrid CDMA/ISMA protocol is evaluated in terms of throughput and delay using computer simulation and mathematical analysis.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Performance Analysis of Slotted ISMA Protocols for Mobile Communications on a Three Lane Motorway
No full textA slotted ISMA protocol has been proposed for using with the communication channel from vehicles to a base station near the motorway. In this report the performance of this channel using the proposed protocol is analysed. Three slotted ISMA protocols can be distinguished, namely: • p-persistent slotted ISMA; • 1-persistent slotted ISMA; • non-persistent slotted ISMA. The performance of the protocol has been measured in terms of the throughput and the packet delay of the communication channel. The system has been modelled by assuming a capture receiver at the base station. The vehicles are assumed to maintain constant velocities while moving in one direction inside a cell of 200 metres on a three-lane motorway. The distribution of the vehicle positions on the motorway has been considered. Also the influence of the packet length and collision detection ratio will be examined. Furthermore the integration of DECT with the designed system is investigated. The performance of the system has been investigated for three traffic types: light traffic, heavy traffic and queuing traffic.Applied SciencesElectrical EngineeringTelecommunications and Traffic-Control Systems Grou
Performance Analysis of a Hybrid ISMA/CDMA Protocol for Indoor Wireless Communication
No full textThe hostile transmission medium encountered in Indoor: Wireless Communications (IWC) requires the use of special communication protocols. In this report we investigate a combination of the Inhibit Sense Multiple Access (ISMA) and Code Division Multiple Access (CDMA) protocols. The ISMA protocol limits the number of simultaneous accesses to the transmission channel and the CDMA protocol improves the packet survival chance. With CDMA each bit is transmitted using several code bits, giving each signal has its own, easy to recognize, signature. Coding spreads the signal over a large transmission bandwidth, which makes it particularly resistant to fading and multipath propagation, two key factors which degrade network performance…Applied SciencesElectrical EngineeringTelecommunications and Traffic Control Systems Grou
Hybrid CDMA / ISMA Protocol in Rician Fading Channel in Indoor Wireles Data Communications
No full textThis thesis describes the performance analysis of a star-connected, indoor wireless computer data communication system using direct-sequence code division multiple access (DS-CDMA) and Hybrid CDMA / Inhibit Sense Multiple Access (ISMA) protocol. The channel performance is investigated in terms of bit error rate (BER) and the protocol performance is investigated in terms of traffic-throughput and throughput-delay characteristics. To enhance the performance, a diversity technique using Maximum Ratio Combining (MRC) is used. Comparison of the simulation results with the analytical results is also performed.Applied SciencesElectrical EngineeringTelecommunications and Traffic Control Systems Grou
Analisis Potensi Erosi pada Das Deli Menggunakan Sistem Informasi Geografis
No full textThe Deli DAS (watershed) is a part of the river area unit of the Wampu River, the Ular River, and the Padang River which has the area of 472.98 square kilometers. It consists of seven sub-watersheds passing the downtown of Medan. The increasing human interaction with Deli watershed has brought about land erosion along the watershed.
A modern technological application which is able to provide the information about the potential erosion, TBE (dangerous erosion level), land sediment, and the flow of land erosion into the river are need in order to know the cause of the increasing incidence of land erosion along the Deli DAS. This information can be used as guidance for decision making in handling the effect of erosion and for discovering why the river is becoming shallow as the result of land erosion. Therefore, it is necessary to conduct a research, entitled, “The Analysis of the Potential Erosion along the Deli DAS (Watershed), Using SIG (Geographical Information System)” which constitutes the composite between Universal Soil Loss Equation (USLE) as the estimation for potential erosion and the Decree of the Minister of Forestry of the Republic of Indonesia in 2009 as the estimation for TBE and Verstraten equation 2007 as the estimation for the sediment flow capacity which was influenced by vegetation with SIG which yielded special data base to become a new information deposit in the potential erosion along the Deli DAS.
The result of the research showed that the Deli DAS underwent five incidences of erosion: very minor damaged (3,138,312 hectares or 6.64%), minor damaged (7,505,460 hectares or 15.87%), moderate (24.019, 166 hectares or 50.78%), heavily damaged (12,013,670 hectares or 25.40%), and seriously damaged (621,423, hectares or 1.31%) with the average erosion annually of 138.808 tons/ha/year or 6,565,344,948 tons/year was in the landmark of moderate erosion class. The implementation of land conservation along the Deli DAS had caused land erosion to decrease around 56.64 tons/ha/year or 59.20%, compared with the amount of land erosion prior to the land conservation. Based on the category of TBE, the Deli DAS was domineered by the criteria of serious danger/ very critical land with the area of 28,760,755 hectares or 60.81% of the total Deli DAS area. The estimation of erosion which flowed to the downstream of sub-Deli Petani DAS was around 2.638 tons/ha/year, sub-Deli Deli DAS was around 3.99 tons/ha/year, sub-Deli Paluh Besar DAS was around 2.291 tons/ha/year, sub-Deli Sei Sekambing DAS was around 0.158 tons/ha/year, sub-Deli Simaimai DAS was around 2.141 tons/ha/year, sub-Deli Babura DAS was around 7.121 tons/ha/year, and sub-Deli Bekala DAS was around 4.619 tons/ha/year. The flow of sediment that occurred along the Deli DAS was 162,288,818 tons/ha/year which yielded sediment volume of 81,144,41 cubic meters so that it was estimated that the cost for taking the river sediment caused by land erosion would be Rp.1, 282, 081,662 per year.Daerah Aliran Sungai (DAS) Deli merupakan salah satu bagian satuan wilayah sungai (WS) Wampu – Ular – Padang yang memiliki luas 472,98 km2
Untuk mengatasi terjadinya erosi tanah yang terus menerus meningkat di DAS Deli, maka diperlukan suatu aplikasi teknologi mutakhir yang mampu menggambarkan informasi potensi erosi, tingkat bahaya erosi (TBE), endapan lahan, dan masuknya erosi tanah ke sungai. Sehingga nantinya berfungsi sebagai pedoman pembuat keputusan untuk penanggulangan dampak erosi dan pendangkalan sungai akibat erosi tanah pada DAS Deli, oleh karena itu perlu dilakukan suatu kajian dengan judul: “Analisis Potensi Erosi pada DAS Deli Menggunakan Sistem Informasi Geografis (SIG)”yang merupakan komposit antara metode Universal Soil Loss Equation (USLE) sebagai pendugaan potensi erosi, peraturan Menteri Kehutanan RI, 2009 sebagai pendugaan tingkat bahaya erosi (TBE), dan persamaan Verstraten, 2007 sebagai pendugaan kapasitas angkutan sedimen yang dipengaruhi vegetasi dengan Sistem Informasi Geografis (SIG) yang menghasilkan basis data spasial menjadi lapisan informasi baru pada potensi erosi di DAS Deli.dan terdiri dari tujuh sub DAS yang langsung melintasi jantung kota Medan, akibat interaksi manusia yang terus meningkat terhadap DAS Deli akan memberikan dampak erosi tanah terhadap DAS tersebut.
Hasil penelitian menunjukkan bahwa DAS Deli mengalami 5 kejadian sebaran erosi, yaitu sangat ringan 3.138,312 ha (6,64 %), ringan 7.505,460 ha (15,87 %), sedang 24.019,166 ha (50,78 %), berat 12.013,670 ha (25,40 %), dan sangat berat 621,423 ha (1,31 %), dengan erosi rata – rata tahunan 138,808 ton/ha/tahun atau 6.565.344,948 ton/thn berada pada tolak ukur kelas erosi sedang, dengan adanya penerapan konservasi tanah di lahan DAS Deli terjadi penurunan erosi tanah sebesar 56,64 ton/ha/tahun atau terjadi persentasi penurunan akibat konservasi lahan sebesar 59,20 % dari besaran erosi sebelum konservasi tanah. Berdasarkan kategori tingkat bahaya erosi (TBE), DAS Deli didominasi pada kriteria sangat bahaya/lahan sangat kritis dengan sebaran luas 28.760,755 ha atau 60,81 % dari total luas DAS Deli. Perkiraan erosi yang masuk ke hilir sungai sub DAS Deli Petani berkisar 2,638 ton/ha/tahun, sub DAS Deli Deli berkisar 3,939 ton/ha/tahun, sub DAS Deli Paluh Besar berkisar 2,291 ton/ha/tahun, sub DAS Deli Sei Sekambing berkisar 0,158 ton/ha/tahun, sub DAS Deli Simaimai berkisar 2,141 ton/ha/tahun, sub DAS Deli Babura berkisar 7,121 ton/ha/tahun, dan sub DAS Deli Bekala berkisar 4,619 ton/ha/tahun. Kemudian pelepasan sedimen yang terjadi di sungai DAS Deli sebesar 162.288,818 ton/tahun yang menghasilkan volume sedimen 81.144,41 m3, maka dapat diperkirakan biaya pengambilan sedimen sungai akibat erosi tanah sebesar Rp . 1.282.081.662/year.359 HalamanTesis Magiste
Studi Karakteristik Muara Sungai Belawan Sumatera Utara
No full textMuara sungai (estuari) merupakan proses tempat terjadinya percampuran dua
masa air antara air laut dan air sungai. Masuknya air laut ke arah hulu sungai (intrusi air
asin) dari hasil pengamatan lapangan pada muara Sungai Belawan diperoleh sekitar 18
km dari mulut estuari menuju arah hulu sungai hingga diperolehnya kandungan
parameter badan air yang tidak terpengaruh salinitas akibat pasut, muara Sungai
Belawan memiliki tipe sudut asin (well-mixed estuary).
Dalam pengamatan karakteristik fisik estuari dilakukan penentuan titik lokasi
yang dimulai dari mulut estuari yang diberi simbol J hingga kearah hulu sungai dengan
simbol A. jarak tiap titik lokasi dari J-A sejauh 18 km dibagi tiap 2 km, kemudian
dilakukan pemodelan dengan bantuan program Microsoft Office Excel menggunakan
rumus – rumus teoritis dari fisik estuari.
kedalaman maksimum berkisar 12 m akibat pasang tertinggi pada jam ke 3 dan
diperoleh penyebaran parameter pada saat pasang tertinggi suhu pada badan air
diperoleh 28.14 ºC dan penyebaran kadar garam diperoleh 26.7 ‰ dan penyebaran zat
padat tersuspensi diperoleh 99.94 mg/l dari kondisi ini badan air pada saat pasang
tertinggi TSS melebihi batas ambang yang diberikan oleh pemerintah menyatakan jika
TSS > 80 mg/l tidak layak untuk kehidupan perikanan, mandi dan selam. Akibat debit
banjir sebesar 697.81 m3/detik yang mempengaruhi penampang muara Sungai Belawan
yang menghasilkan aliran sungai sebesar 0.19 m/det yang akan mendorong kecepatan
arus pasut yang terjadi pada model fisik estuari , maka diperoleh intrusi air laut masuk
kedalam sungai berkurang sejauh 6 km dari kondisi pada saat debit sebesar 15 m3/detik
sehingga intrusi air asin yang masuk kedalam sungai sejauh 12 km188 HalamanSkripsi Sarjan
Studi Karakteristik Muara Sungai Belawan Sumatera Utara
No full textMuara sungai (estuari) merupakan proses tempat terjadinya percampuran dua
masa air antara air laut dan air sungai. Masuknya air laut ke arah hulu sungai (intrusi air
asin) dari hasil pengamatan lapangan pada muara Sungai Belawan diperoleh sekitar 18
km dari mulut estuari menuju arah hulu sungai hingga diperolehnya kandungan
parameter badan air yang tidak terpengaruh salinitas akibat pasut, muara Sungai
Belawan memiliki tipe sudut asin (well-mixed estuary).
Dalam pengamatan karakteristik fisik estuari dilakukan penentuan titik lokasi
yang dimulai dari mulut estuari yang diberi simbol J hingga kearah hulu sungai dengan
simbol A. jarak tiap titik lokasi dari J-A sejauh 18 km dibagi tiap 2 km, kemudian
dilakukan pemodelan dengan bantuan program Microsoft Office Excel menggunakan
rumus – rumus teoritis dari fisik estuari.
kedalaman maksimum berkisar 12 m akibat pasang tertinggi pada jam ke 3 dan
diperoleh penyebaran parameter pada saat pasang tertinggi suhu pada badan air
diperoleh 28.14 ºC dan penyebaran kadar garam diperoleh 26.7 ‰ dan penyebaran zat
padat tersuspensi diperoleh 99.94 mg/l dari kondisi ini badan air pada saat pasang
tertinggi TSS melebihi batas ambang yang diberikan oleh pemerintah menyatakan jika
TSS > 80 mg/l tidak layak untuk kehidupan perikanan, mandi dan selam. Akibat debit
banjir sebesar 697.81 m3/detik yang mempengaruhi penampang muara Sungai Belawan
yang menghasilkan aliran sungai sebesar 0.19 m/det yang akan mendorong kecepatan
arus pasut yang terjadi pada model fisik estuari , maka diperoleh intrusi air laut masuk
kedalam sungai berkurang sejauh 6 km dari kondisi pada saat debit sebesar 15 m3/detik
sehingga intrusi air asin yang masuk kedalam sungai sejauh 12 km188 HalamanSkripsi Sarjan
Throughput analysis of some mobile packet radio protocols in Rician fading Channels
No full textThe throughput of packet radio channels is investigated theoretically using the interference model in Rician fading environment. Three types of packet protocols are considered, namely: i) slotted ALOHA, ii) unslotted nonpersistent ISMA, and iii) slotted nonpersistent ISMA. Numerical results are presented, indicating the effect of propagation impairments on channel capacity. The results are of importance for mobile data networks, wireless office communications and other packet systems with contention-limited performance.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
STUDI KESEIMBANGAN AIR (WATER BALANCED) DAERAH ALIRAN SUNGAI ASAHAN
No full textAbstrak Pemanasan Global (Global Warming) telah menyebabkan perubahan iklim yang sangat ekstrem didukung dengan adanya perubahan tataguna lahan di dalam cakupan daerah aliran sungai mengakibatkan dampak yang cukup buruk terhadap kondisi keseimbangan air (Water Balanced). Daerah Aliran Sungai Asahan merupakan salah satu DAS yang memiliki peran yang penting sebagai sumber air dalam memenuhi kebutuhan air di Kabupaten Asahan. Kondisi lahan yang berubah menjadi kritis akibat adanya eksploitasi dan perubahan tataguna lahan mengakibatkan ketersediaan air berkurang dalam memenuhi kebutuhan air. Tujuan penelitian yaitu menganalisis keseimbangan air (Water Balanced) antara jumlah ketersediaan air dengan kebutuhan air di sekitar cakupan Daerah Aliran Sungai Asahan. Lingkup kegiatan penelitian yaitu menganalisis ketersediaan air atau debit andalan dengan probabilitas 90% dengan metode FJ Mock, menganalisis kebutuhan air irigasi, domestik, non domestik, dan menganalisis keseimbangan air (Water Balanced) di tiap lokasi titik pengambilan dengan prinsip pengurangan antara jumlah ketersediaan air dengan kebutuhan air di sepanjang cakupan DAS Asahan dari hulu sampai dengan hilir. Hasil penelitian menunjukan bahwasanya ketersediaan air DAS Asahan paling minimum dengan probabilitas 90% yaitu 34.96 m3/det dapat memenuhi total kebutuhan air DAS Asahan baik itu irigasi, domestik, dan non domestik yaitu 13.00 m3/det. Kata kunci: Keseimbangan air, ketersediaan air, kebutuhan air, DAS Asahan Abstract Global Warming has caused extreme climate change supported by changes in land use within the watershed area resulting in quite bad impact on water balanced conditions. Asahan Watershed is one of the catchment areas which has an important role as the source to supply water requirement in the Asahan District. Land used changes become critical due to exploitation and changes in land use have reduced water availability to fill water requirement. The objective of this research to analysis water balanced between the total water availability and water requirement in the Asahan Watershed. The scopes of this research are analysis water availability or dependable flow using FJ Mock, analysis irrigation water requirement, domestic, nondomestic, and water balanced in each node with the reduction principle between total of water availability and water requirement in the Asahan Watershed from upstream to downstream. Result of this research showed that the lowest water availability Asahan Watershed with probability 90% is 56.43 m3/sec can fill the total of water irrigation, domestic, and non-domestic is 14.80 m3/sec. Keywords: Water balanced, water availability, water requirement, Asahan watershe
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