Effect of nitrogen rates on the whitefly (Bemisia tabaci) population infesting chilli (Capsicum annum L.)

Bemisia tabaci (Gennadius) is considered the most important whitefly species harmful to agriculture. Experiments were conducted at MARDI Station in Jalan Kebun, Klang, Selangor from 9 September 2006 to 11 November 2007. The objective of this study was to evaluate the population of whitefly on chilli plants fertilised with different rates of nitrogen (0, 33, 43, 53 g/plant). The results showed that high rates of nitrogen treatment significantly (P<0.05) increased B. tabaci immature population as compared to lower rate treatments. The mean number of B. tabaci immature per plant stratum was significantly different (P<0.05) among plant strata as well as among the treatments. Generally, the mean number of B. tabaci eggs and larvae was significantly (P<0.05) greater in the upper strata than in the middle and lower plant strata. Whereas, the mean number of B. tabaci pupa was significantly greater in the lower strata than in the upper and middle plant strata. The mean number of B. tabaci immature was significantly different (P<0.05) among the sampling periods in all treatment. Generally, B. tabaci population was significantly greater during the early season and gradually declined as the season progressed except during the third and seventh week after transplanting

Dynamic window secured implicit geographic forwarding for wireless sensor network.

Routing security is a major concerned in Wireless Sensor Network since a large scale of unattended nodes is deployed in ad hoc fashion with no possibility of a global addressing due to a limitation of node's memory and the node have to be self organizing when the systems require a connection with the other nodes. It becomes more challenging when the nodes have to act as the router and tightly constrained on energy and computational capabilities where any existing security mechanisms are not allowed to be fitted directly. These reasons thus increasing vulnerabilities to the network layer particularly and to the whole network, generally. In this paper, a Dynamic Window Secured Implicit Geographic Forwarding (DWSIGF) routing is presented where a dynamic time is used for collection window to collect Clear to Send (CTS) control packet in order to find an appropriate hoping node. The DWIGF is expected to minimize a chance to select an attacker as the hoping node that caused by a blackhole attack that happen because of the CTS rushing attack, which promise a good network performance with high packet delivery ratios

The impact of window's size in DWSIGF routing protocol.

In this study, different collection window's size is been analyzed to investigate the impact on network performance: packet delivery ratio, message overhead and end to end delay on the Dynamic Window Secured Implicit Geographic Forwarding (DWIGF) routing protocol where this protocol is based on a dynamic collection window approached. Its method on using dynamic window's size has minimized the probability of selecting attackers and guaranteed high packet delivery ratios when there is a blackhole attack in the communication link. The DWSIGF is then compared with the best chosen window's size to analyze the network performance with and without attacker in the communication line, respectively. The DWIGF is able to minimize a Clear To Send (CTS) rushing attack that leads to a blackhole and selectively forwarding attack with a guaranteed of high packet delivery ratios where a selection of a failed trade and all attacker is minimized, respectively. As a result, this routing protocol is promising a dynamic and secured communication without inserting any existing security mechanism inside

An Improved Optimization Model of Internet Charging Scheme in Multi Service Networks

This article will analyze new improved charging scheme with base price, quality premium and QoS networks involved. Sain and Herpers [5] already attempted to obtain revenue maximization by creating charging scheme of internet. The plan is attempted to solve multi service networks scheme as an optimization model to obtain revenue maximization using our improved model based on Byun and Chatterjee [2] and Sain and Herpers [5]. The results show that improved model can be solved optimally using optimization tool LINGO to achieve better revenue maximization. Better results are obtained in all cases rather than in [5]. The advantage of our new model is that ISP also can set up their base price and quality premium based on ISP preferences. For some cases for getting revenue maximization, we do not offer one service and just utilize some of the services

Impact of Denial-of-Service Attack on Directional Compact Geographic Forwarding Routing Protocol in Wireless Sensor Networks

يَعِدُ بروتوكول التوجيه، الموجه الجغرافي المضغوط (DCGF) بتوليد الحد الأدنى من النفقات العامة من خلال استخدام هوائي ذكي وتجميع واعٍ لجودة الخدمة (QoS). ومع ذلك، تم اختبار DCGF فقط في سيناريو خالٍ من الهجمات دون إشراك عناصر الأمان.  لذلك، تم إجراء استقصاء لفحص خوارزمية بروتوكول التوجيه فيما إذا كانت آمنة ضد الشبكات القائمة على الهجوم بوجود هجوم رفض الخدمة (DoS).  تم إجراء هذا التحليل على هجوم DoS باستخدام مهاجم واحد مثالي، A1، للتحقيق في تأثير هجوم DoS على DCGF في خط اتصال.  أظهرت الدراسة أن   DCGF لا يعمل بكفاءة من حيث نسبة تسليم الحزم واستهلاك الطاقة حتى على مهاجم واحد.Directional Compact Geographic Forwarding (DCGF) routing protocol promises a minimal overhead generation by utilizing a smart antenna and Quality of Service (QoS) aware aggregation. However, DCGF was tested only in the attack-free scenario without involving the security elements. Therefore, an investigation was conducted to examine the routing protocol algorithm whether it is secure against attack-based networks in the presence of Denial-of-Service (DoS) attack. This analysis on DoS attack was carried out using a single optimal attacker, A1, to investigate the impact of DoS attack on DCGF in a communication link. The study showed that DCGF does not perform efficiently in terms of packet delivery ratio and energy consumption even on a single attacker

Production of semi- refined carrageenan from Eucheuma cotonii.

This study presents alkaline extraction of red seaweed, Eucheuma cotonii, to yield semi-refined carrageenan (SRC) of kappa type. Temperatures 60-80°C were suitable for extraction of SRC. At 80°C using 1.0 M KOH, produced SRC contained the highest purity of 3, 6-anhydrogalactose, a lower heavy metal concentration and gave highest rupture force

MEH-PPV film thickness influenced fluorescent quenching of tip-coated plastic optical fiber sensors

The performance of plastic optical fiber sensors in detecting nitro aromatic explosives 1,4-dinitrobenzene (DNB) have been investigated by fluorescence spectroscopy and analyzed by using fluorescence quenching technique. The plastic optical fiber utilized is 90 degrees cut tip and dip-coated with conjugated polymer MEH-PPV poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] thin films for detection conjugants. The thicknesses of the MEH-PPV coating were varied to improvise the sensitivity whilst slowly reducing the fluorescence intensity. It was shown that fluorescence intensity from thinner film decreased by (82% in 40 s) in the presence of DNB signifying an improvement of 28% reduction with time 13 s less than that of the thicker film

Random traveling wave pulse coupled oscillator (RTWPCO) algorithm of energy-efficient wireless sensor networks

Energy-efficient pulse-coupled oscillators have recently gained significant research attention in wireless sensor networks, where the wireless sensor network applications mimic the firefly synchronization for attracting mating partners. As a result, it is more suitable and harder to identify demands in all applications. The pulse-coupled oscillator mechanism causing delay and uncharitable applications needs to reduce energy consumption to the smallest level. To avert this problem, this study proposes a new mechanism called random traveling wave pulse-coupled oscillator algorithm, which is a self-organizing technique for energy-efficient wireless sensor networks using the phase-locking traveling wave pulse-coupled oscillator and random method on anti-phase of the pulse-coupled oscillator model. This technique proposed in order to minimize the high power utilization in the network to get better data gathering of the sensor nodes during data transmission. The simulation results shown that the proposed random traveling wave pulse-coupled oscillator mechanism achieved up to 48% and 55% reduction in energy usage when increase the number of sensor nodes as well as the packet size of the transmitted data compared to traveling wave pulse-coupled oscillator and pulse-coupled oscillator methods. In addition, the mechanism improves the data gathering ratio by up to 70% and 68%, respectively. This is due to the developed technique helps to reduce the high consumed energy in the sensor network and increases the data collection throughout the transmission states in wireless sensor networks

Impact of the deafness problem on clock synchronization in a wireless sensor network

Observations of natural phenomena are considered to be the best information source of spontaneous synchronization. Natural phenomena tend to match wireless sensor network (WSN) responses closely. Such synchronization is vital for the proper coordination of power cycles for energy conservation. A large number of fireflies employ the principle of pulse-coupled oscillators for light flash emission to attract mating partners. With respect to WSNs, the nodes are generally unable to afford packet transmission and reception simultaneously, thus preventing complete network synchronization. This paper presents a literature overview concerning the impact of the deafness problem on clock synchronization in a WSN. Data transmission based on synchronization can also be ensured through the optimization of energy usage periodic data capturing in a WSN. This study serves as a useful information source of clock synchronization to assist WSN researchers and novices in obtaining a better understanding of the impact of the deafness problem on clock synchronization and to enable them to promote effective designs and systems that address this problem