346 research outputs found

    Writing on Fading Paper and Causal Transmitter CSI

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    A wideband fading channel is considered with causal channel state information (CSI) at the transmitter and no receiver CSI. A simple orthogonal code with energy detection rule at the receiver (similar to [6]) is shown to achieve the capacity of this channel in the limit of large bandwidth. This code transmits energy only when the channel gain is large enough. In this limit, this capacity without any receiver CSI is the same as the capacity with full receiver CSI--a phenomenon also true for dirty paper coding. For Rayleigh fading, this capacity (per unit time) is proportional to the logarithm of the bandwidth. Our coding scheme is motivated from the Gel'fand-Pinsker [2,3] coding and dirty paper coding [4]. Nonetheless, for our case, only causal CSI is required at the transmitter in contrast with dirty-paper coding and Gel'fand-Pinsker coding, where non-causal CSI is required. Then we consider a general discrete channel with i.i.d. states. Each input has an associated cost and a zero cost input "0" exists. The channel state is assumed be to be known at the transmitter in a causal manner. Capacity per unit cost is found for this channel and a simple orthogonal code is shown to achieve this capacity. Later, a novel orthogonal coding scheme is proposed for the case of causal transmitter CSI and a condition for equivalence of capacity per unit cost for causal and non-causal transmitter CSI is derived. Finally, some connections are made to the case of non-causal transmitter CSI in [8]

    Rate transient analysis and completion optimization study in Eagle Ford shale

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    Master's Project (M.S.) University of Alaska Fairbanks, 2015Analysis of well performance data can deliver decision-making solutions regarding field development, production optimization, and reserves evaluation. Well performance analysis involves the study of the measured response of a system, the reservoir in our case, in the form of production rates and flowing pressures. The Eagle Ford shale in South Texas is one of the most prolific shale plays in the United States. However, the ultra-low permeability of the shale combined with its limited production history makes predicting ultimate recovery very difficult, especially in the early life of a well. Use of Rate Transient Analysis makes the analysis of early production data possible, which involves solving an inverse problem. Unlike the traditional decline analysis, Rate Transient Analysis requires measured production rates and flowing pressures, which were provided by an operator based in the Eagle Ford. This study is divided into two objectives. The first objective is to analyze well performance data from Eagle Ford shale gas wells provided by an operator. This analysis adopts the use of probabilistic rate transient analysis to help quantify uncertainty. With this approach, it is possible to systematically investigate the allowable parameter space based on acceptable ranges of inputs such as fracture length, matrix permeability, conductivity and well spacing. Since well spacing and reservoir boundaries were unknown, a base case with a reservoir width of 1500 feet was assumed. This analysis presents a workflow that integrates probabilistic and analytical modeling for shale gas wells in an unconventional reservoir. To validate the results between probabilistic and analytical modeling, a percent difference of less than 15% was assumed as an acceptable range for the ultimate recoverable forecasts. Understanding the effect of existing completion on the cumulative production is of great value to operators. This information helps them plan and optimize future completion designs while reducing operational costs. This study addresses the secondary objective by generating an Artificial Neural Network model. Using database from existing wells, a neural network model was successfully generated and completion effectiveness and optimization analysis was conducted. A good agreement between the predicted model output values and actual values (R² = 0.99) validated the applicability of this model. A completion optimization study showed that wells drilled in condensate-rich zones required higher proppant and liquid volumes, whereas wells in gas-rich zones required closer cluster spacing. Analysis results helped to identify wells which were either under-stimulated or over-stimulated and appropriate recommendations were made

    Vendor managed forecasting: A case study of small enterprise

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    Enterprises use supply chain management practices for improving business or supply chain performance. It is observed that supply chain technologies like VMI are now becoming an integral part of enterprise’s strategy. Even small and medium enterprises can adopt this practice and improve the performance of supply chain. This paper discusses vendor managed forecasting with the help of case study. It shows how a small enterprise improves supply chain performance by using demand related information obtained from retailer. The results obtained in the study shows that vendor managed forecasting in supply chain reduces the demand variation and improves inventory management significantly.Peer Reviewe

    Lateral distal tibial locking compression plate fixation through single lateral incision technique is biologically superior and mechanically equivalent alternative to medial plate fixation for lower third tibia-fibula fractures

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    Background: A number of surgical options for management of distal tibia fractures makes scenario confusing and available techniques are associated with complications. Recently lateral plating of tibia has shown good promise. To compare results between medial and lateral distal tibial locking compression plate for treatment of distal third tibia fracturesMethods: Prospective clinical study was carried out among 24 patients presenting with distal third tibia fractures. Patients were randomized into two groups of 12 each. One group was allocated into medial distal tibial LCP and second group was allocated into lateral distal tibial LCP. In first group, approach taken was medial or anteromedial while in second group, approach taken was lateral. Follow up was done for six months after surgery.Results: There were 10 cases in medical group and eight cases in lateral group which had fracture due to road traffic accidents. All cases in medical group had concomitant fibula fracture while such cases were 10 in lateral group. One case in each group developed infection after surgery. There was one case of superficial skin dehiscence and one case of hardware problem in medial group compared to none in lateral group. Two cases from medial group required removal of implant compared to none from medial group.Conclusions: Lateral distal tibial LCP seems to provide biological advantage than medial distal tibial LCP without difference in biomechanical properties of implants. Single lateral incision technique is an ingenious, biologically sound, and cosmetically superior for fixation of both lower third tibia & fibula fractures together

    Minimal permutation representations for linear groups

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    In this paper we study the minimal faithful permutation representations of SLn(Fq)SL_n(\mathbb F_q) and GLn(Fq)GL_n(\mathbb F_q).Comment: 30 pages, submitted. arXiv admin note: substantial text overlap with arXiv:2005.1221

    Performance Analysis of Different Optimization Algorithms for Multi-Class Object Detection

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    Object recognition is a significant approach employed for recognizing suitable objects from the image. Various improvements, particularly in computer vision, are probable to diagnose highly difficult tasks with the assistance of local feature detection methodologies. Detecting multi-class objects is quite challenging, and many existing researches have worked to enhance the overall accuracy. But because of certain limitations like higher network loss, degraded training ability, improper consideration of features, less convergent and so on. The proposed research introduced a hybrid convolutional neural network (H-CNN) approach to overcome these drawbacks. The collected input images are pre-processed initially through Gaussian filtering to eradicate the noise and enhance the image quality. Followed by image pre-processing, the objects present in the images are localized using Grid Guided Localization (GGL). The effective features are extracted from the localized objects using the AlexNet model. Different objects are classified by replacing the concluding softmax layer of AlexNet with Support Vector Regression (SVR) model. The losses present in the network model are optimized using the Improved Grey Wolf (IGW) optimization procedure. The performances of the proposed model are analyzed using PYTHON. Various datasets are employed, including MIT-67, PASCAL VOC2010, Microsoft (MS)-COCO and MSRC. The performances are analyzed by varying the loss optimization algorithms like improved Particle Swarm Optimization (IPSO), improved Genetic Algorithm (IGA), and improved dragon fly algorithm (IDFA), improved simulated annealing algorithm (ISAA) and improved bacterial foraging algorithm (IBFA), to choose the best algorithm. The proposed accuracy outcomes are attained as PASCAL VOC2010 (95.04%), MIT-67 dataset (96.02%), MSRC (97.37%), and MS COCO (94.53%), respectively

    The role of modified biophysical profile in predicting perinatal outcome in high risk pregnancies

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    Background: The goal of antepartum fetal surveillance is early identification of the compromised fetus and timely intervention when the fetus is at risk, but still in an uncompromised state. Modified Biophysical Profile (MBPP) includes Amniotic Fluid Index (AFI) and non stress test (NST). AFI is a marker of long term placental function and NST is a marker of short term fetal condition. The aim of this study is to assess the role of Modified Biophysical Profile in high risk pregnancies and assess perinatal outcome and to study the impact of NST and AFI individually in high risk pregnancies.Methods: 100 ANC patients with high risk factors were evaluated with modified biophysical profile 37 week onwards with non stress test (NST) for 20 mins and amniotic fluid index (AFI) with 4 quadrant technique. High risk pregnancies include preeclampsia, IUGR, oligohydramnios, postdated pregnancy, etc. and various parameters were assessed to determine perinatal and maternal morbidity. All parameters were statistically analyzed.Results: The above study states that need for LSCS, intrapartum fetal distress, meconium stained liquor, APGAR score, need for neonatal resuscitation and perinatal morbidity were definitely higher in cases with abnormal MBPP.Conclusions: Thus MBPP is an easy, cost effective and time saving measure and hence can be used as a primary antepartum fetal surveillance test to predict perinatal outcome and provide timely intervention in high risk pregnancies
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