614 research outputs found

    Sensor Scheduling for Energy-Efficient Target Tracking in Sensor Networks

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    In this paper we study the problem of tracking an object moving randomly through a network of wireless sensors. Our objective is to devise strategies for scheduling the sensors to optimize the tradeoff between tracking performance and energy consumption. We cast the scheduling problem as a Partially Observable Markov Decision Process (POMDP), where the control actions correspond to the set of sensors to activate at each time step. Using a bottom-up approach, we consider different sensing, motion and cost models with increasing levels of difficulty. At the first level, the sensing regions of the different sensors do not overlap and the target is only observed within the sensing range of an active sensor. Then, we consider sensors with overlapping sensing range such that the tracking error, and hence the actions of the different sensors, are tightly coupled. Finally, we consider scenarios wherein the target locations and sensors' observations assume values on continuous spaces. Exact solutions are generally intractable even for the simplest models due to the dimensionality of the information and action spaces. Hence, we devise approximate solution techniques, and in some cases derive lower bounds on the optimal tradeoff curves. The generated scheduling policies, albeit suboptimal, often provide close-to-optimal energy-tracking tradeoffs

    Sensor Management for Tracking in Sensor Networks

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    We study the problem of tracking an object moving through a network of wireless sensors. In order to conserve energy, the sensors may be put into a sleep mode with a timer that determines their sleep duration. It is assumed that an asleep sensor cannot be communicated with or woken up, and hence the sleep duration needs to be determined at the time the sensor goes to sleep based on all the information available to the sensor. Having sleeping sensors in the network could result in degraded tracking performance, therefore, there is a tradeoff between energy usage and tracking performance. We design sleeping policies that attempt to optimize this tradeoff and characterize their performance. As an extension to our previous work in this area [1], we consider generalized models for object movement, object sensing, and tracking cost. For discrete state spaces and continuous Gaussian observations, we derive a lower bound on the optimal energy-tracking tradeoff. It is shown that in the low tracking error regime, the generated policies approach the derived lower bound

    Association between Low Adiponectin Level and Cardiovascular Complications in Diabetic and non Diabetic Patients with End Stage Renal Disease

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    Introduction: Adiponectin is a collagen-like protein synthesized by adipose tissue that has anti-inflammatory and anti-atherogenic properties. We aimed to evaluate adiponectin levels in end stage renal disease (ESRD) patients with and without diabetes mellitus and its relation to the presence of cardiovascular complications (CVC). Methods: The study included 20 healthy subjects who served as controls (group I), 20 non-diabetic ESRD patients without CVC (group IIA), 20 non-diabetic ESRD patients with CVC (group IIB), 20 diabetic ESRD patients without CVC (group IIIA) and 20 diabetic ESRD patients with CVC (group IIIB). Evaluation included mean arterial blood pressure (MABP), body mass index (BMI), fasting plasma glucose, fasting plasma insulin, homeostasis model assessment for insulin resistance (HOMA-IR), lipid profile, and serum adiponectin levels. Results: Adiponectin level in the control group was 6.4±1.2 mcg/ml, and was significantly lower than both group II and III (

    Localization and composition of seed oils of Crithmum maritimum L. (Apiaceae)

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    The use of some halophytes for rehabilitation of salt affected area has been reported. Crithmum maritimum L. halophyte and apiaceae can tolerate high levels of salt. Their seed was endospermic and had a suitable size for oil extraction. The aim of this report is to localize the lipids in the seed and determine their oils composition. The results showed that the lipids were accumulated in endosperm tissue as oil globoids. The percentage of oils was 44.4% dry weight basis. The C. maritimum L. seed oil was rich with oleic acid (78.6%), low level of palmitic acid (4.8%) and non negligible amount of linoleic acid (15.4%). This composition is similar to olive oil and canola oil. These results confirmed the good quality of C. maritimum L. seed oils.Keys word: Halophytes; Crithmum maritimum L.; seed oils

    Effect of Irrigation Water Salinity on Some Soil Properties and Wheat Yield in Egypt

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    Wheat plant (Triticum aestivum, sakha-8) was grown in pot experiment to study the effect of salinity levels and salt composition of irrigation water with and without N fertilization on soil chemical properties and grain yield of wheat plant. Therefore surface soil samples of nonsaline silty clay loam soil was used. Tap water was salinized to be as natural irrigation water in the studied region using mixture of CaCl2, MgCl2 and NaCl at different ratios. Three salinity levels were prepared from different mixture to give nine type of irrigation water and tap water was used as control treatment. Soil salinity after plant harvesting increased with increasing water salinity up to 12.70 dS/m compared with it before planting (2.23 dS/m) or after harvesting using irrigation with good water (2-79dS/m).On the other side, soil reaction (pH) decreased from 8.17 to 7.65 with increasing water salinity. Values of sodium adsorption ratio (SAR) for soil solution also increased from 3.65 up to 11.24 and soil exchangeable sodium percentage (ESP) was correlated with soil SAR, where it increased from 4.24 to 11.91%. Soil content of available N and P almost decreased with increasing water salinity after plant harvesting. The results indicated that the grain yield was significantly decreased either with increasing salinity levels or Na concentration in irrigation water used. This effect was decreased with added-N, where grain yield was increased by about 2 to 3 fold compared with it without N fertilization under this conditions. Grain content of Na was increased to give less quality of grain yield. Plant uptake of Na decreased with increasing levels of added –N

    Development Strategy of the Facility Traditional Fish Landing Sites (Mediator) in the Village of West Bagan, Bangko Subdistrict, Rokan Hilir, Riau Province

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    Village of West Bagan is a village with a population of the second largest fishermen in the district of Bangko, RokanHilir, Riau Province. Fishermen of the West Bagan village, land and sell their catch in private mediators. However, the facilities available are not enough to meet the needs of fishing supplies consisting of fuel, fresh water and ice. Therefore, this research with survey method was undertaken to obtain the development strategy of the facility by using SWOT analysis. From 9 units mediator were still active, taken 3 units mediator as representatives of large, medium, and small category namely are consecutevely Jumadi mediator, Lausi mediator, dan Asmara mediator. Based on SWOT analysis has been done on each of the mediators obtained one most likely to be develop is mediator Jumadi. In the diagram strategy, mediator Jumadi located in quadrant I with the highest coordinate value, which is a provitable situation. Recommendations strategyis progressive, which means the mediator has the opportunity and the power that can take advantage of existing opportunities. The strategy applied in this condition is to support aggressive growth policy

    Kandungan Logam Berat Pb, Cu dan Zn pada Siput Hitam (Faunus Ater) dari Perairan Muara Sungai Air Bangis Sumatera Barat

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    Analysis of lead, copper and zinc in black snail (Faunus ater) in Air Bangis estuary was conducted in August 2014 with the aim to determine the pollution level in the estuary as well as to evaluate the safety of the snail for human consumption. The result showed that the average concentration of lead was 7.91 μg/g, copper 10.58 μg/g and zinc 65.11 μg/g. Higher metal concentration was found in the muscle body and smaller size of tha snail accumulated higher concentration of the metals studied. The MPI value of 75.28 in the estuary is categorize as can be tolerated by aquatic organisms. PTWI calculation for lead (0.88 kg/week), copper (92.8 kg/week) and zinc (30.09 kg/week) indicated that the snail from Air Bangis estuary is still considered to be safe for human consumption
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