Gradient based adaptive thresholding

For images with poor and non-uniform illumination, adaptive thresholding is required to separate the objects of interest from the background. In this paper a new approach to create an adaptive threshold surface is proposed to segment an image. The technique is inspired by the Yanowitz’s method and is improved upon by the introduction of a simpler and more accurate threshold surface. The method is tested on several images of different patterns with varying illumination and the results are compared to the ones produced by a number of adaptive thresholding algorithms. In order to demonstrate the effectiveness, the proposed method had been implemented in medical and document images. The proposed method compares favorably against those using watershed and morphology in medical image and favorably against variable threshold and adaptive Otsu’s N-thresholding for document image.     

Analytical analysis of applying packet fragmentation mechanism on IEEE 802.11b DCF network in non ideal channel with infinite load conditions

The analytical modeling and performance analysis of the 802.11 network in all its various extensions (802.11b, 802.11a, 802.11g, 802.11e, 802.11n, etc.) have already been widely explored over the past years. However, the packet fragmentation mechanism (PFM), which is proposed by the IEEE work group to reduce the impact of bit error rate (BER) on the packet error rate (PER), has not been considered in the analytical models proposed in the literature. Yet, the PFM constitutes a key parameter to achieve the best performances of 802.11 networks. In this paper, we extend the Bianchi’s Markov chain model with the PFM and the PER. Then, we analyze the performance improvement level achieved with the PFM in an IEEE 802.11 network under the impact of BER and packet length. The proposed analysis has been applied on the basic access method of 802.11b network in saturated traffic conditions. So, we have analyzed the throughput and the mean response time of the 802.11 network. The obtained theoretical results are validated by simulation.     

Modeling and performance evaluation of the IEEE 802.15.4e LLDN mechanism designed for industrial applications in WSNs

The IEEE 802.15.4 standard has been introduced for low latency and low energy consumption in wireless sensor networks. To better support the requirements of industrial applications, where the use of this standard is limited, the low latency deterministic network (LLDN) mechanism of the IEEE 802.15.4e amendment has been proposed. In this paper, we develop a three dimensional Markov chain model for the IEEE 802.15.4e LLDN mechanism. Then, we estimate the stationary probability distribution of this chain in order to derive theoretical expressions of some performance metrics, as the reliability, energy consumption, throughput, delay and jitter. After that, we conduct a comparative study between the IEEE 802.15.4e LLDN and the IEEE 802.15.4 slotted carrier sense multiple access with collision avoidance (CSMA/CA). Numerical results show that the deterministic behavior of the LLDN mechanism significantly reduces the collision probability providing best performances in terms of reliability, energy consumption, throughput and delay compared to the IEEE 802.15.4 slotted CSMA/CA. Finally, the accuracy of our theoretical analysis is validated by Monte Carlo simulations.     

Effect on Mechanical Performance of UHMWPE/HDPE-Blend Reinforced with Kenaf,Basalt and Hybrid Kenaf/Basalt Fiber

The aim of this study was to investigate the performance of UHMWPE/HDPE-reinforced kenaf, basalt and hybrid kenaf/basalt composites. Mechanical testing of these samples was carried out such as tensile, flexural (three-point bending) and an impact test (Charpy). Pure resin (UHMWPE/HDPE) samples were tested and compare with reinforced 10% weight fraction of kenaf, basalt and hybrid kenaf/basalt samples to identifying their contribution and potential in this new composite material. UHMWPE/ HDPE sample was produced in constant ratio 60:40 respectively via extrusion process. Basalt reinforced UHMWPE/HDPE generates the highest elastic modulus result compared to kenaf and hybrid kenaf/basalt as a reinforcement material. The tensile results of kenaf reinforcement UHMWPE/HDPE samples are significantly higher (20%) than pure blend resin, which is an indication for good performance of kenaf, basalt and hybrid kenaf/basalt to be used in UHMWPE/HDPE-blend polymers. The flexural and Charpy strengths show the drawback results, where performance of polymer is reduced 5% with the absence of kenaf. It can be concluded that kenaf, basalt and hybrid kenaf/basalt fiber successfully increase the UHMWPE/HDPE blends performance especially under tensile loading.     

Evaluation of Adh1 alleles and transgenic soybean seeds using Scorpion PCR and HRM analysis

The identification of both approved and non-approved genetically modified organisms (GMOs) is an integral part of GMO biosafety legislation in many countries. One aspect that may affect PCR-based detection of a GMO lies within the analysis of its genetic stability, as sequence alterations or DNA instabilities may impede quantification by PCR. Genetic stability can be analyzed using various methods, yet many of these methods have distinct disadvantages, including low sensitivity. In this study, high resolution melting (HRM) analysis and real-time PCR with Scorpion primers were used as a method to analyze the 3′ end of RR soybeans (RR 40-3-2) in a large number of samples (n = 1,034). No evidence for the occurrence of mutation events was found, implying that the nucleotide sequence of this region is unlikely to be unstable and is well suited as a target for the quantification of RR soybeans. Additionally, and as a preparative work for an optimization of the method, a 174 bp region of the first intron of the Adh1 gene was analyzed in several varieties of maize with different GMO events using the same approach. The results show that 2 alleles are present. In further experiments, the different alleles were cloned into plasmids to generate homozygous plasmids from heterozygous templates in order to generate for a more precise analysis. The overall methodological aim of these studies was to compare HRM analysis with Scorpion primer PCR. Both methods were capable of differentiating between the 2 homozygous and heterozygous alleles. For a better discrimination, however, we conclude that it is most reliable to consider the results of both methods. This dual approach is assumed to be an effective tool as an accurate, high-throughput means of the screening of GMOs for potential genetic instabilities that may interfere with the detection and identification of specific GM events.     

Carbon control policies, competitiveness, and border tax adjustments

Several propositions have recently been made to use border tax adjustments (BTAs) to address the loss of competitiveness induced by unilateral stringent domestic pollution control policies. This paper explores in a general equilibrium framework the sectoral and welfare implications of a unilateral domestic GHG control policy combined with a BTA scheme. Using the Canadian economy as an illustration, we assess the extent to which BTAs achieve their objectives and analyze the impacts of different methods of recycling the BTA proceeds to support domestic industries. Our simulation results suggest that imposing BTAs on the imports of non-fossil and energy-intensive products reduces or removes completely the negative competitiveness impacts that domestic industries suffer from. The use of the proceeds of the BTAs to support domestic energy-intensive industries improves their competitiveness and, more importantly, in some cases, overprotects them, as it allows them to even increase their output in comparison to the benchmark without emissions control. Our results also shed light on the existence of heterogeneity in the composition of energy-intensive industries as far as the recycling method of the BTA proceeds is concerned. Energy-intensive industries that are more oriented toward the domestic market are better off with the recycling of the BTA proceeds towards gross output than towards exports alone. Finally, abstracting from the environmental benefits of reduced emissions, we find that a BTA entails a higher welfare cost to households.     

Mechanical,morphological, and thermal properties of poly(vinyl chloride)/low‐density polyethylene composites filled with date palm leaf fiber

This article investigates the mechanical, morphological, and thermal properties of poly(vinyl chloride) (PVC) and low‐density polyethylene (LDPE) blends, at three different concentrations: 20, 50, and 80 wt% of LDPE. Besides, composite samples that were prepared from PVC/LDPE blend reinforced with different date palm leaf fiber (DPLF) content, 10, 20, and 30 wt%, were also studied. The sample in which PVC/LDPE (20 wt%/80 wt%) had the greatest tensile strength, elongation at break, and modulus. The good thermal stability of this sample can be seen that T_10% and T_20% occurred at higher temperatures compared to others blends. DPLF slightly improved the tensile strength of the polymer blend matrix at 10 wt% (C10). The modulus of the composites increased significantly with increasing filler content. Ageing conditions at 80°C for 168 h slightly improved the mechanical properties of composites. Scanning electron microscopic micrographs showed that morphological properties of tensile fracture surface are in accordance with the tensile properties of these blends and composites. Thermogravimetric analysis and derivative thermogravimetry show that the thermal degradation of PVC/LDPE (20 wt%/80 wt%) blend and PVC/LDPE/DPLF (10 and 30 wt%) composites took place in two steps: in the first step, the blend was more stable than the composites. In the second step, the composites showed a slightly better stability than the PVC/LDPE (20 wt%/80 wt%) blend. Based on the above investigation, these new green composites (PVC/LDPE/DPLF) can be used in several applications. J. VINYL ADDIT. TECHNOL., 25:E88–E93, 2019. © 2018 Society of Plastics Engineers     

Discrete Convexity, Straightness, and the 16-Neighborhood

In this paper, we extend some results in discrete geometry based on the 8-neighborhood to that of the 16-neighborhood, which now includes the chessboard and the knight moves. We first present some analogies between an 8-digital arc and a 16-digital arc as represented by shortest paths on the grid. We present a transformation which uniquely maps a 16-digital arc onto an 8-digital arc (and vice versa). The grid-intersect-quantization (GIQ) of real arcs is defined with the 16-neighborhood. This enables us to define a 16-digital straight segment. We then present two new distance functions which satisfy the metric properties and describe the extended neighborhood space. Based on these functions, we present some new results regarding discrete convexity and 16-digital straightness. In particular, we demonstrate the convexity of a 16-digital straight segment. Moreover, we define a new property for characterizing a digital straight segment in the 16-neighborhood space. In comparison to the 8-neighborhood space, the proposed 16-neighborhood coding scheme offers a more compact representation without any loss of information.     

Minimizing the makespan in the non-preemptive job-shop scheduling with limited machine availability

This paper addresses the makespan minimization in a job-shop environment where the machines are not available during the whole planning horizon. The disjunctive graph model is used to represent the schedules and the concept of blocks is generalized to include the unavailability periods of machines. To solve the problem, we develop a taboo thresholding heuristic that uses a new block-based neighborhood function. Some sufficient conditions to eliminate the evaluation of non-improving moves are proposed. Experiments performed on existing problem instances of the literature show the efficiency of the proposed heuristic.