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Sugar palm is a plant that has many benefits in human life. One of the most popular is water sap which is made to produce palm sugar, and even palm plants can also be produced to produce flour. This study aimed to identify the parts contained in the sugar palm plant and the sap produced by the sugar palm plant in GN Riting Village, Membalong Belitung District. This research was conducted to identify the parts contained in one sugar palm plant and the production of sap produced by sugar palm plants. The research method used in this study is a survey method with a sampling technique using purposive sampling. Based on the results of a survey conducted by researchers, the height of the sugar palm stem is 580 cm, the number of leaves is 11 leaves, the number of Mayang is seven female Mayang, 2-3 male Mayang, and fruit length is 39.8 cm, and the resulting sap production is 30 liters.

Management of Interference Is the solution designing for LTE network to reduce inter symbol interference (ISI) and intercell interference (ICI) using the frequency reuse schemes which has the objective to maximize the coverage area and provide more capacity in cells, especially in cell edge. Based on those propositions, this paper analyzes the process of optimizing subcarrier and power allocation for wireless networks with multi-level soft frequency reuse (ML-SFR). In this case, LTE network planning has to maximize the coverage area of the Cimahi city, especially for maximizing the user in cell edge to obtain a good performance. Based on the analysis throughput, carrier to interference noise, quality by the coverage, and signal power level comparison between SFR and ML-SFR that has been done, the ML-SFR method can produce better performance because it was able to increase quality by coverage 0,03, increase throughput to 2.422,08 kbps, increase C/(I+N) to 4,41 dB and increase signal power level as well to 12,51 dBm.

Multiple-Input Multiple-Output (MIMO) systems that realize high-speed data transmission with multiple antennas at both transmitter and receiver are drawing much attention. In line-of sight (LOS) environments, the performance of MIMO systems depends largely on the difference of the phase difference of direct paths from transmit antennas to each receive antenna. When the phase difference of direct paths are close to each other, the spatial division multiplexing (SDM) channels are not orthogonal to each other so signal detection becomes difficult. In this paper, we propose a MIMO system with relative phase difference time-shift modulation (RPDTM) in Rician fading environments. The proposed scheme transmits independent signals from each antenna at each time slot where the relative phase difference between signal constellations used by transmit antennas varies in a pre-determined pattern. This transmission virtually changes the phase difference of direct paths from transmit antennas to each receive antenna without lowering data rate and without knowledge of the channels. In addition, forward error correction coding (ECC) is applied to exploit the time slots where the receiver can detect the signals easily to improve the detection performance. If there are time slots where the receiver can separate the received signal, the receiver can decode the data by using the time slots and the correlation between data. From the results of computer simulation, we show that MIMO system with RPDTM can achieve the better bit error rate (BER) than the conventional MIMO system. We also show that the MIMO system with RPDTM is effective by about Rician factor K=10dB.

Improvement on throughput of cognitive radio networks is possible by spectrum sensing when the required sample number (sensing time) is relatively small. This is due to the fact that when the sample number for sensing is smaller, time for a cognitive radio user to transmit is larger. This paper presents a scheme of sequential detector which has average sample number lower than its counterpart, a quadratic detector with a fixed sample number. A sequential detector as per se has a high computational complexity under correlated observations due to the need to compute the inverse and determinant of the signal covariance matrix for every sample acquired before finally deciding. The paper studies how to reduce the computational complexity using circulant matrix approximations of the signal covariance matrix, so that the calculations of the inverse and the determinant are replaced by simpler methods. Reductions on computational complexity are quantified and the performances are evaluated by simulations.

In recent years, Pre-Rake combining technique has become a hot topic of research as it decreases the complexity of the portable mobile unit, while achieving the same multipath diversity effect of the Rake receiver. The technique is based on precoding of the transmitted signal relying on knowledge of the channel estimation response before transmission. This a priori channel state information is available in Time Division Duplexing (TDD) systems, since the same channel is used both in uplink and downlink. In practice, the error in channel estimation in Pre-Rake system occurs due to time variability in mobile radio channel. Most previous works on Pre-Rake in TDD CDMA have not taken into consideration the effect of imperfect channel estimation. In this paper, we present Pre-Rake performance under imperfect channel estimation due to time variability in TDD system, depending on Doppler Frequency and compare it with the ideal Pre-Rake system. Numerical analysis and computer simulations were carried out to obtain the system error probability.

The application process for entry into public universities in Malaysia, handled entirely by the University Centre Unit (UPU), has a major drawback as often the degree programme offered to students does not match their field of interest. The Degree Selection System (DSS) used for this study is designed to assist students to select the most appropriate degree programmes that match their field of study. The methodology used in this study is the Analytical Hierarchy Process (AHP) while Holland's Six Personality Types is used to identify the student's field of interest. The expected finding will display a list of programmes that matches the students' field of interest and they will have the freedom to choose eight of them.

In this paper we present the experimental implementation of dynamic spectrum access (DSA) algorithm using universal software radio peripheral (USRP) and GNU Radio. The setup contains two primary users and two cognitive radios or secondary users. One primary user is fixed and the other is allowed to change its position randomly. Depending upon the position of the primary user the cognitive user will use the spectrum band where the detected energy is below certain predefined threshold level. The cognitive radio users are also programmed to operate independently without interfering with each other using energy detection algorithm for spectrum sensing. The modulation scheme is set to GMSK for secondary user performing data transmission. This experimental setup is used to analyze the quality of video transmission using DSA which provides the insight regarding the possibility of using free spectrum space to improve the performance of the system and its advantage over a non-DSA system. From the experiment it is shown that under congestion and interference DSA perform better than a non- DSA system.

The paper presents results of collision probability evaluation of a one-to-many reversible mapping between user space and IPv6 address space which is developed to improve of IPv6 addresses generation in a local area network (LAN). Each time a user accesses the network, a dynamic unicast IPv6 address is given via DHCPv6 (Dynamic Host Configuration Protocol for IPv6) server to protect users from unwanted behavior analysis exploiting IPv6 addresses, thus protecting user privacy. This IPv6 address is generated dynamically using CFB (Cipher Feedback) mode of AES (Advanced Encryption Standard) algorithm based on user identity. The dynamic address can be uniquely linked to user if the need arises to allow network administrator to identify user based on captured IPv6 address during any security event. Checksum has been used for validation of probability of coincidental match of randomly generated Interface Id or generated by some other mechanism. The collision probability of the one-to-many reversible mapping for stateful IPv6 address assignment is evaluated using birthday paradox. The results show that the collision probability is very small indeed. The one-to-many reversible mechanism may be incorporated as an extension to the current DHCPv6 software.

The recent massive critical data leaks by Wikileaks suggest how fragile national security is from the perspective of information system and network sustainability. This incident raises some causes of concern. Firstly, critical infrastructure such as military and diplomatic systems is not spared from security breach. Secondly, such leak causes far-reaching damage to public interests, national security and economic sustainability. And thirdly, both technology and law seem incapable of dealing with such situation. Malaysia is not spared from the risk of information security attacks. Its ten critical sectors as identified in its National Cyber Security Policy (NCSP) -national defence and security; banking and finance; information and communications; energy, transport and water; government, emergency and medical services; as well as food and agriculture-can at any time fall victim to security breaches and data leaks if efforts to protect their system are flawed. The objective this paper is to outline the problems and challenges from the points of legal framework that Malaysia should anticipate and address in maintaining and sustaining its national CII. The paper first look at the problem of data breaches in the world and examine how as the technology becomes more superior, the cyber-world becomes more vulnerable to data breaches. Tied to that is the notion of critical information infrastructure (CIIs). As more and more of these CIIs are connected and dependent on connectivity, the normal incidence of data breach can be a potential of human loss and catastrophe. The paper next look at the concept of critical information security in Malaysia and examine the seriousness of data breaches in Malaysia. The paper seeks to explore legal options that Malaysia can adopt in preparing itself to more data breaches onslaught. It is the basic contention of the paper that the traditional legal framework should be reformed in line with the advances of the information and communications technologies.

In this paper we propose a scheme that provides physical layer security by combining two techniques known as encryption and channel pre-compensation. Encryption transforms the original signal constellation into a higher order constellation based on the key sequence generated by AES in counter-mode. Channel pre-compensation is performed based on the knowledge of channel, which is location specific, at the transmitter. These two techniques distort the original signal constellation which can only be recovered by the intended receiver. The proposed scheme not only makes the estimation of the constellation difficult but also the type of modulation that is used for the adversary. BER (bit error rate) is used as performance metric. We find that the adversary suffers from high BER as compared to the legitimate user; hence providing secure communication.

In this paper we consider the problem of secure communication between two nodes, over a fading wireless medium, in the presence of a passive eavesdropper. We propose a scheme that provides security based on transforming the basic signal constellation to a higher order signal constellation with the help of conventional encryption method and then using channel knowledge (i.e. amplitude and phase variation), which is location specific, to distort the constellation of encrypted data. This scheme not only makes the estimation of the constellation difficult but also the type of modulation that is used for the adversary. BER (bit error rate) is used as performance metric. We find that the adversary suffers from high BER as compared to its legitimate counterpart.

In line-of sight (LOS) environments, the performance of Multiple-Input Multiple-Output (MIMO) systems depends largely on the difference of the phase difference of direct paths from transmit antennas to each receive antenna. When the phase difference of direct paths are close to each other, the spatial division multiplexing (SDM) channel is not orthogonal to each other so that the signal detection becomes difficult. In this paper, we propose a MIMO system with relative phase difference time-shift modulation (RPDTM) in Rician fading environments. The proposed scheme transmits independent signals from each antenna at each time slot where relative phase difference between signal constellations used by transmit antennas varies with a pre-determined pattern. This transmission virtually changes the phase difference of direct paths from transmit antennas to each receive antenna without lowering data rate and without knowledge of the channels. In addition, forward error correction coding (ECC) is applied to exploit the time slots where the receiver can detect the signals easily to improve the detection performance. From the results of computer simulation, we show that MIMO system with RPDTM can achieve the better bit error rate (BER) than the conventional MIMO system. We also show that the MEMO system with RPDTM is effective by about Rician factor K = 10 dB.

Array low density parity check (LDPC) codes are high-rate codes that can achieve good error rate performance in additive white Gaussian noise (AWGN) channels. However, array LDPC codes do not support arbitrary code lengths, because the code length of an array LDPC code with good error rate performance is limited to a multiple of a prime number. This paper proposes Size Compatible (SC)-array LDPC codes; they achieve good error rate performance while supporting arbitrary code lengths. We conduct computer simulations to evaluate the block error rate (BLER) performance of SC-array LDPC codes in AWGN channels. We also evaluate the corresponding performance of SC-array LDPC coded multiband OFDM systems for data transmission rates over 1 Gbps in the UWB multipath channel model CM 3. We show that if the submatrix size is a non- prime number, SC-array LDPC codes achieve better error rate performance than the conventional array LDPC codes in AWGN channels. We also show that the SC-array LDPC codes achieve better error rate performance than the punctured array LDPC codes in AWGN channels. We also show that if the submatrix size is a prime number, SC-array LDPC codes achieve the same error rate performance as conventional array LDPC codes in AWGN channels. Moreover, we show that for multiband OFDM systems with data transmission rates of over 1 Gbps, SC-array LDPC codes achieve better error rate performance than conventional array LDPC codes.

In this paper, we evaluate packet error rate (PER) performances of high data rate multiband OFDM systems over 1 Gbps in CM 3 using irregular structured LDPC code, simplified LDPC code, and array LDPC code. We also evaluate the decoding complexities of simplified LDPC code and array LDPC code with code rates of R = 3/4,7/8, when belief propagation (BP) algorithm is used. From simulation results, we show that at data transmission rates of 640, 960 Mbps, simplified LDPC codes have the best error rate performances, and at data transmission rate of 1120 Mbps, array LDPC code has better error rate performances than simplified LDPC code. We also show that the order of decoding complexity for array LDPC code and simplified LDPC codes are same.

Among new technologies, ultra wideband (UWB) is gathering interests as a short-reach transmission system. At present, as one of the prevailing UWB systems, the multiband-orthogonal frequency division multiplexing (MB-OFDM) system has attracted much attention where convolutional code (CC) is used. The main contribution of this paper is to evaluate the bit error rate (BER) and decoding complexity performances of MB-OFDM with concatenated coding scheme and dual carrier modulation (DCM) on IEEE 802.15.3a UWB multipath channel model. We employ the CC for the inner code and the Reed Solomon (RS) code for the outer code in the concatenated coding scheme. From the results of our computer simulation, we show good combination of coding rates in the concatenated coding scheme at the data rates of about 320, 400 480 Mbps. We also show that MB-OFDM with concatenated coding scheme can achieve the better BER than MB-OFDM with only CC. In addition, we show that the BER improvement of MB-OFDM with concatenated coding scheme over that with only CC becomes larger as the data rate becomes higher.

This paper proposes pre-Rake combining schemes for TDD multi-carrier DS/CDMA in the reverse link. Pre-Rake diversity in the reverse link could effectively exploit the channel information of MC/CDMA in the forward link, without significant complexity increase, because the channel estimation part, which is usually the most complex and power-consuming part in a Rake receiver, in this case is the channel estimation used by the receiver to demodulate the received signal. Since MC/DS-CDMA uses several subcarriers, several pre-Rake schemes could be considered. In the first scheme, pre-Rake combining is done after the multi-carrier symbol is converted into time domain signal, the structure of this type of pre-Rake is similar with that used in a single carrier DS/CDMA system. In the second scheme, pre-Rake is performed in each subcarrier of MC/DS-CDMA, prior to MC modulation. The latter scheme is more flexible when the channel condition and the delay profile of each subcarrier is different one to another. The performance of the proposed system is compared using computer simulation.

This paper proposes subcarrier selection in conjunction with variable spreading factor to be applied in the reverse link of TDD multi-carrier/DS-CDMA system, to improve the system performance, against multiple access interference (MAI), in frequency selective fading channel, without reducing the throughput of the system. In frequency selective fading channel, MC/DS-CDMA subcarrier suffers from different attenuation, and when some subcarriers are severely faded, it may cause significant effect of MAI, and thus degrade the system performance. To avoid this, we apply subcarrier selection method that selects the subcarriers that are in good channel condition for transmission, thus the transmission will use a part of available subcarriers. In order to avoid throughput degradation due to this method, we employ variable spreading factor that adjust the spreading factor of each user depends on the number of subcarriers used for the transmission. Moreover, the proposed method is very easy to be realized in TDD system using the reciprocity of forward and reverse link. The performance of proposed method is evaluated using computer simulation.

A method of transmission power control (TPC) for orthogonal frequency division multiplexing direct sequence code division multiple access (OFDM-DS-CDMA), in order to compensate for power attenuation at each subcarrier, is proposed. Instead of assigning the same power levels for all-subcarriers, different transmission power levels are assigned to different subcarriers, according to the attenuation of the subcarriers. System performance, in terms of bit error rate (BER), has been evaluated by Monte Carlo simulation. The simulation results presented significant improvement; the proposed system performed much better than the system without TPC. It is shown that the each-carrier TPC performed better than all-carrier TPC, hence each-carrier TPC is more suitable for OFDM-DS-CDMA systems.

This paper investigates a TDD/CDMA scheme, where Multi-carrier DS/CDMA with Pre-Rake diversity in the reverse link could effectively exploits the channel information of MC/CDMA in the forward link. The possibility of Pre-Rake combining among delay path elements whose interval is less than the chip length of the reverse link spreading sequence. The performance of the proposed system is evaluated in terms of the bit error rate performance, as a function of number of paths within one chip, and number of Pre-Rake fingers. Computer simulation shows that Pre-Rake combining among path elements within a chip give some improvement gain. However, the gain is much less than the improvement gain from the path diversity across several chips as in conventional Pre-Rake.

An Each Carrier Transmission Power Control with Antenna-Carrier Diversity is investigated for the reverse link of OFDM DS-CDMA system. Power control is used to compensate for non uniform attenuation level at each subcarrier due to frequency selective fading by assigning different transmission level in each sub carrier. And antenna-carrier diversity is used to minimize reception of strong attenuated signals which unable to be compensated by power control because of power limitation in mobile station. It was confirmed through computer simulation that proposed system achieved better performance in terms of bit error rate probability.