Browsing by Author "Kissaka, Mussa"

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    Access Authorization and Monitoring for Web Based Resources for e-Learning System for Secondary Schools in Tanzania
    (2007-11-16) Mkocha, K.; Kissaka, Mussa; Mwinyiwiwa, B. M. M.
    This paper presents the development of a mechanism for the authorization and monitoring of data for a web based e-learning system. System data as well as the different user groups accessing the data have been defined. Constraints to use the LAMP solution stack, the UML models are coded in PHP which is embedded in the HTML. These interfaces are used as doorways through which different users, as per their role, can access and work on the system data according to their clearance. On the other hand, the administrator can see different reports, from system logs by simply pressing a button.
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    Analysis of Powerline Channel Model for Communication from Primary Substation Node to End-Users
    (Winter-Spring, 2004) Anatory, Justinian; Mvungi, Nerey H.; Kissaka, Mussa;
    Abstract—The low voltage power networks in developing countries like Tanzania are designed without taking into consideration their application in data communication. In order to use them for data communication, powerline channel models have been developed and analysed in order to understand the factors that will affect the transmission. In this paper transfer characteristics of powerline channel from power users to primary substation have been modeled and analyzed. Simulation results show that the signal in PLC environment attenuates more with interconnections, which needs to be amplified/regenerated within a few meters.
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    Analysis of the Architecture and MAC Protocol for Power-line Networks
    (2003) Iddi, Hashim U.; Kissaka, Mussa; Mvungi, Nerey H.
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    Appropriate Technology for Electrical Power Metering in Tanzania
    (2004) Anatory, Justinian; Kissaka, Mussa; Mvungi, Nerey H.
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    Asynch-NET: Footstep for Always-On e-Services in the Rural Areas of Developing Countries: Case Study-Tanzania
    (2006-07-12) Greyson, K.; Kissaka, Mussa; Haule, D.; Ndume, V.
    The asynchronous network (Asynch-NET) provided by mobile access point (MAP) in the community of rural areas of developing countries has proved success in many regions of the developing countries. This asynchronous network is the footstep for e-services implementation in the communities with low-income and low population density. Basically, the cost of implementing a conventional "always-on" link in the rural areas of developing countries is very high that does not attract investors to put effort on. The paper presents a technique that is applied to the Asynch-NET framework so as to provide "the always-on" e-services at the similar operating cost of Asynch-NET.
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    Broadband Power Line Communications: Analysis of Indoor Power Line Network in Developing Countries
    (JKUAT, 2006) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.
    The effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) are presented in this paper. The power line network topology adopted here is similar to that of the system found in Tanzania. Investigation on effects of network load impedances, direct transmitter to receiver line length, branched line length and numbers of branches have been carried out. The frequency response of the power line transfer function shows that position of notches and peaks in the magnitude and phase responses are largely affected by the above network parameters particularly attenuation and dispersion. The response was also observed in the time domain. The observations made in this work could be useful in the design of high performance PLC systems for data transfer
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    Broadband Power Line Communications: Analysis of Indoor Power Line Network in Developing Countries
    (JKUAT, 2006) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.
    The effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) are presented in this paper. The power line network topology adopted here is similar to that of the system found in Tanzania. Investigation on effects of network load impedances, direct transmitter to receiver line length, branched line length and numbers of branches have been carried out. The frequency response of the power line transfer function shows that position of notches and peaks in the magnitude and phase responses are largely affected by the above network parameters particularly attenuation and dispersion. The response was also observed in the time domain. The observations made in this work could be useful in the design of high performance PLC systems for data transfer
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    Broadband Power line Communications: Performance Analysis: transactions on Engineering, Computing and Technology
    (2006-12) Anatory, Justinian; Kissaka, Mussa; Theethayi, Nelson; Mvungi, Nerey H.
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    Broadband Power Line Communications: The factors Influencing Wave Propagations in the Medium Voltage Lines
    (IEEE, 2007-03) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.
    This paper presents the influencing of load impedance, line length and branches on the performance of medium voltage power line communication (PLC) network. The power line network topology adopted here is similar to that of the system in Tanzania. Different investigation with regard to network load impedances, direct line length (from transmitter to receiver), branched line length and number of branches has been investigated. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude responses are largely affected in terms of attenuation and dispersion by the above said network parameters/configuration. The observations presented in the paper could be helpful in suitable design of the PLC systems for a better data transfer and system performance.
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    Broadband Power Line Communications: The factors Influencing Wave Propagations in the Medium Voltage Lines
    (IEEE, 2007) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.
    this paper presents the influencing of load impedance, line length and branches on the performance of medium voltage power line communication (PLC) network. The power line network topology adopted here is similar to that of the system in Tanzania. Different investigation with regard to network load impedances, direct line length (from transmitter to receiver), branched line length and number of branches has been investigated. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude responses are largely affected in terms of attenuation and dispersion by the above said network parameters/configuration. The observations presented in the paper could be helpful in suitable design of the PLC systems for a better data transfer and system performance.
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    Broadband Power-Line Communication Channel Model: Comparison between Theory and Experiments
    (IEEE, 2008) Anatory, Justinian; Theethayi, Nelson; Thottappillil, Rajeev; Kissaka, Mussa; Mvungi, Nerey H.
    Recently different models have been proposed for analyzing the BPLC systems based on transmission line (TL) theory. In this paper one such BPLC model is validated using laboratory experiments by comparing the channel transfer functions. A good agreement between the BPLC model based on TL theory and experiments is found for channel frequencies up to about 100MHz
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    Broadband Power-Line Communications: The Channel Capacity Analysis
    (IEEE, 2008-01) Anatory, Justinian; Kissaka, Mussa; Theethayi, Nelson; Thottappillil, Rajeev; Mvungi, Nerey H.
    The power line has been proposed as a solution to deliver broadband services to end users. Various studies in the recent past have reported a decrease in channel capacity with an increase in the number of branches for a given channel type whether it is an indoor or low-voltage (LV) or medium-voltage (MV) channel. Those studies, however, did not provide a clear insight as to how the channel capacity is related to the number of distributed branches along the line. This paper attempts to quantify and characterize the effects of channel capacity in relation to the number of branches and with different terminal loads for a given type of channel. It is shown that for a power spectral density (PSD) between 90 dBm/Hz to 30 dBm/Hz, the channel capacity decreases by a 20-30 Mb/s/branch, 14-24 Mb/s/branch, and a 20-25 Mb/s/branch for an MV channel, LV channel, and indoor channel, respectively. It is also shown that the channel capacity is minimum when the load impedance is terminated in characteristic impedances for any type of channel treated here. It is shown that there could be a significant loss in channel capacity if a ground return was used instead of a conventional adjacent conductor return. The analysis presented in this paper would help in designing appropriate power-line communication equipment for better and efficient data transfer.
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    Broadband PowerLine Communications: Performance Analysis
    (World Academy of Science, Engineering and Technology, 2008) Anatory, Justinian; Theethayi, Nelson; Kissaka, Mussa; Mvungi, Nerey H.
    Power line channel is proposed as an alternative for broadband data transmission especially in developing countries like Tanzania [1]. However the channel is affected by stochastic attenuation and deep notches which can lead to the limitation of channel capacity and achievable data rate. Various studies have characterized the channel without giving exactly the maximum performance and limitation in data transfer rate may be this is due to complexity of channel modeling being used. In this paper the channel performance of medium voltage, low voltage and indoor power line channel is presented. In the investigations orthogonal frequency division multiplexing (OFDM) with phase shift keying (PSK) as carrier modulation schemes is considered, for indoor, medium and low voltage channels with typical ten branches and also Golay coding is applied for medium voltage channel. From channels, frequency response deep notches are observed in various frequencies which can lead to reduce the achievable data rate. However, is observed that data rate up to 240Mbps is realized for a signal to noise ratio of about 50dB for indoor and low voltage channels, however for medium voltage a typical link with ten branches is affected by strong multipath and coding is required for feasible broadband data transfer
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    Broadband Services Provision in Powerline Communications of Developing Countries
    (IEEE, 2005) Anatory, Justinian; Mvungi, Nerey H.; Kissaka, Mussa
    Recently it has been identified that powerline network is the promise cost effective for broadband accessibility compared to competitors technology. Since, powerline channel has been designed to provide electricity, using it for broadband communication various issues have to be addressed. These include channel characterization, noise, modulation to be used, coding etc. The topology of powerline network affects the transfer characteristics of the channel. In this paper the powerline channel problems have been modeled for utilization by broadband access. In addition different techniques such as application of modulation, and coding have been addressed and the simulation results have been discussed.
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    Channel Model for Broadband Power line Communication
    (IEEE, 2007-01) Anatory, Justinian; Kissaka, Mussa; Mvungi, Nerey H.
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    Characterizing the Factors Influencing Electromagnetic Interference (EMI) and Radiation (EMR) in Outdoor Broadband Power-line Communication (BPLC) Systems
    (Institute for Experimental Mathematics, 2010-06) Anatory, Justinian; Kissaka, Mussa; Naiman; Hamad, O. F.
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    Computing and Communications View graph of relations The Design of a Mixed-Mode Integrated Circuit to Implement a New Decoding Algorithm
    (HW Communications Limited, 1993) Kissaka, Mussa; King, D.; Markarian, G. S.; Honary, Bahram
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    Determination of Maximum Data Transmission Distance in Powerline Networks in Developing Countries
    (2004-07) Anatory, Justinian; Kissaka, Mussa; Mvungi, Nerey H.
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    Determination of Maximum Data Transmission Distance in Powerline Networks in Developing Countries
    (EAJST, 2004) Anatory, Justinian; Mvungi, Nerey H.; Kissaka, Mussa
    Recently, Powerline communications has been considered for providing broadband access services and as a cost effective means of connectivity to non-urban and lowly populated areas. This indicates that it is a viable technology for developing countries like Tanzania where there is adequate penetration of the powerline networks. However, the use of the network for data transmission presents a number of problems that limits achievable transmission distances (hops). This paper looks at different modulation and coding techniques to maximize transmission distance