Bug Fix Time Optimization Using Matrix Factorization and Iterative Gale-Shaply Algorithms

Bug triage is an essential task in software maintenance phase. It assigns developers (fixers) to bug reports to fix them. This process is performed manually by a triager, who analyzes developers profiles and submitted bug reports to make suitable assignments. Bug triaging process is time consuming thus automating this process is essential to improve the quality of software. Previous work addressed triaging problem either as an information retrieval or classification problem. This paper tackles this problem as a resource allocation problem, that aims at the best assignments of developers to bug reports, that reduces the total fixing time of the newly submitted bug reports, in addition to the even distribution of bug reports over developers. In this paper, a combination of matrix factorization and Gale Shapely algorithm, supported by the differential evolution is firstly introduced to optimize the total fix time and normalize developers work load. Matrix factorization is used to establish a recommendation system for Gale-Shapley to make assignment decisions. Differential evolution provides the best set of weights to build developers score profiles. The proposed approach is assessed over three repositories, Linux, Apache and Eclipse. Experimental results show that the proposed approach reduces the bug fixing time, in comparison to the manual triage, by 80.67%, 23.61% and 60.22% over Linux, Eclipse and Apache respectively. Moreover, the workload for the developers is uniform.Comment: 14 page, 7 figures, 8 tables, 10 equation

Genetic and morphological identification of some crabs from the Gulf of Suez, Northern Red Sea, Egypt

AbstractMost crab species inhabiting the Red Sea have not been characterized morphologically and genetically. In the current work, five different crab species were collected from the northern part of the Egyptian Red Sea. They were morphologically identified through description of colors, dentations of the carapace and shapes of chelipeds and pereiopods. They were also genetically characterized by the partial sequencing of the barcode region in the mitochondrial cytochrome oxidase subunit I (COI) gene, which is known to be hypervariable among different crab species. Morphological and genetic characterization identified the crab species as: Charybdis (Charybdis) hellerii (A. Milne-Edwards, 1867), Charybdis (Charybdis) natator (Herbst, 1794), Portunus (Portunus) pelagicus (Linnaeus, 1758), Liocarcinus corrugatus (Pennant, 1777), and Atergatis roseus (Rüppell, 1830). This is the first record of L. corrugatus in the Egyptian Red Sea, despite being previously recorded in the Indian and Atlantic Ocean as well as in the Mediterranean Sea. DNA barcoding with precise morphological identification was effective in characterizing the crab species collected from the Egyptian Red Sea water

Comparison between Results of Microdiscectomy and Open Discectomy in Management of High-Level Lumbar Disc Prolapse

AIM: This work aims to compare between results of microdiscectomy and open discectomy in management of high-level lumbar disc prolapse. METHODS: This is a controlled randomised study, where patients having upper lumbar disc herniations were evaluated preoperatively both clinically and radiologically, randomisation was planned to perform open discectomy in odd number patients and to perform microdiscectomy in even number patients, patients were evaluated and followed up for deficits and outcomes. RESULTS: We operated ten patients in this study, five cases were operated upon with microdiscectomy, and five cases were operated upon with open discectomy, the median age of presentation in this study was 44 years, there were five males and five females, postoperative pain improvement was better in microdiscectomy. Hospital stay, blood loss, bone loss and postoperative complications were less in microdiscectomy. CONCLUSION: Microdiscectomy allows good surgical visualisation and is less traumatic to the involved tissues. The results of this study indicated that microsurgery reduces hospitalisation time, improves the overall surgery-related outcome. The main differences between the two procedures were the length of the incision and blood loss. We found that lumbar microdiscectomy allows patients earlier return to work and normal life with less reliance on postoperative narcotic analgesic agents

Postfault operation of five-phase induction machine with minimum total losses under aingle open-phase fault

Five-phase induction machines (FPIM) have attracted notable interest in safety critical applications as well as wind energy generation systems. This is largely due to their additional degrees of freedom that retain the machine starting/running steadily under fault conditions. In the available literature, postfault operation of multiphase machines is typically implemented using two techniques: minimum losses (ML) or maximum torque per ampere (MT) strategies. The optimization embedded into the control strategy, however, mostly addresses minimization of the stator copper loss, while the effect of the rotor loss and core loss are discarded in the optimal current calculation. This paper revisits postfault operation of the FPIM under single open phase fault (1OPF) by including the effect of both rotor loss and core loss on the machine's optimal current calculation over the full achievable loading range. The proposed searching algorithm, which combines the advantages of both MT and ML techniques, attempts to minimize the total machine losses induced by the current components of both the fundamental \alpha \beta and the secondary xy subspaces. The theoretical findings have been experimentally validated using a 1.5Hp five-phase prototype system

Broadcast Authentication for Wireless Sensor Networks Using Nested Hashing and the Chinese Remainder Theorem

Secure broadcasting is an essential feature for critical operations in wireless sensor network (WSNs). However, due to the limited resources of sensor networks, verifying the authenticity for broadcasted messages is a very difficult issue. μTESLA is a broadcast authentication protocol, which uses network-wide loose time synchronization with one-way hashed keys to provide the authenticity verification. However, it suffers from several flaws considering the delay tolerance, and the chain length restriction. In this paper, we propose a protocol which provides broadcast authentication for wireless sensor networks. This protocol uses a nested hash chain of two different hash functions and the Chinese Remainder Theorem (CRT). The two different nested hash functions are employed for the seed updating and the key generation. Each sensor node is challenged independently with a common broadcasting message using the CRT. Our algorithm provides forward and non-restricted key generation, and in addition, no time synchronization is required. Furthermore, receivers can instantly authenticate packets in real time. Moreover, the comprehensive analysis shows that this scheme is efficient and practical, and can achieve better performance than the μTESLA system

Genetic Diversity and Population Structure of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing

The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes (F3:6) derived from various crosses as a prerequisite for GWAS and genomic selection. Genotyping-by-sequencing provided 25,566 high-quality SNPs. The polymorphism information content (PIC) across chromosomes ranged from 0.09 to 0.37 with an average of 0.23. The distribution of SNPs markers on the 21 chromosomes ranged from 319 on chromosome 3D to 2,370 on chromosome 3B. The analysis of population structure revealed three subpopulations (G1, G2, and G3). Analysis of molecular variance identified 8% variance among and 92% within subpopulations. Of the three subpopulations, G2 had the highest level of genetic diversity based on three genetic diversity indices: Shannon’s information index (I) = 0.494, diversity index (h) = 0.328 and unbiased diversity index (uh) = 0.331, while G3 had lowest level of genetic diversity (I = 0.348, h = 0.226 and uh = 0.236). This high genetic diversity identified among the subpopulations can be used to develop new wheat cultivars

GWAS revealed effect of genotype × environment interactions for grain yield of Nebraska winter wheat

Background: Improving grain yield in cereals especially in wheat is a main objective for plant breeders. One of the main constrains for improving this trait is the G × E interaction (GEI) which affects the performance of wheat genotypes in different environments. Selecting high yielding genotypes that can be used for a target set of environments is needed. Phenotypic selection can be misleading due to the environmental conditions. Incorporating information from phenotypic and genomic analyses can be useful in selecting the higher yielding genotypes for a group of environments. Results: A set of 270 F3:6 wheat genotypes in the Nebraska winter wheat breeding program was tested for grain yield in nine environments. High genetic variation for grain yield was found among the genotypes. G × E interaction was also highly significant. The highest yielding genotype differed in each environment. The correlation for grain yield among the nine environments was low (0 to 0.43). Genome-wide association study revealed 70 marker traits association (MTAs) associated with increased grain yield. The analysis of linkage disequilibrium revealed 16 genomic regions with a highly significant linkage disequilibrium (LD). The candidate parents’ genotypes for improving grain yield in a group of environments were selected based on three criteria; number of alleles associated with increased grain yield in each selected genotype, genetic distance among the selected genotypes, and number of different alleles between each two selected parents. Conclusion: Although G × E interaction was present, the advances in DNA technology provided very useful tools and analyzes. Such features helped to genetically select the highest yielding genotypes that can be used to cross grain production in a group of environments

Authenticated Key Agreement with Rekeying for Secured Body Sensor Networks

Many medical systems are currently equipped with a large number of tiny, non-invasive sensors, located on, or close to, the patient’s body for health monitoring purposes. These groupings of sensors constitute a body sensor network (BSN). Key management is a fundamental service for medical BSN security. It provides and manages the cryptographic keys to enable essential security features such as confidentiality, integrity and authentication. Achieving key agreement in BSNs is a difficult task. Many key agreement schemes lack sensor addition, revocation, and rekeying properties, which are very important. Our proposed protocol circumvents these shortcomings by providing node rekeying properties, as well as node addition and revocation. It proposes a key distribution protocol based on public key cryptography—the RSA (Rivest, Shamir and Adleman) algorithm, and the DHECC (Diffie-Hellman Elliptic Curve Cryptography) algorithm. The proposed protocol does not trust individual sensors, and partially trusts the base station (hospital). Instead of loading full pair-wise keys into each node, after installation our protocol establishes pair-wise keys between nodes according to a specific routing algorithm. In this case, each node doesn’t have to share a key with all of its neighbors, only those involved in the routing path; this plays a key role in increasing the resiliency against node capture attacks and the network storage efficiency. Finally we evaluate our algorithm from the BSN security viewpoint and evaluate its performance in comparison with other proposals

IL-10 Gene polymorphism and graft outcome in live-donor kidney transplantation

Background: The description of polymorphisms in many of the key immunoregulatory molecules involved in the rejection process has offered a possible explanation for the individual variation in susceptibility to rejection and differences in allograft survival independent of the many known contributory factors. The aim of this work is to study the impact of IL-10 cytokine gene polymorphism on renal transplant clinical course and outcome.Methods: This work studied 50 transplant recipients maintained on sirolimus based immunosuppression for IL-10 cytokine gene polymorphisms. After transplantation patients were divided into two groups. Group (A) patients (12 patients) received sirolimus, tacrolimus and steroid, while Group (B) patients (38 patients) received sirolimus, mycophenolate mofetil and steroid. Results were correlated with acute and chronic rejection episodes as well as graft and patient outcome.Results: In our study, we found no impact of IL-10 on incidence and degree of acute rejection episodes, incidence of chronic allograft nephropathy, pathological changes in protocol biopsies, graft function and graft and patient survivals.  Conclusion: From this work, we can conclude that the potential impact of IL-10 cytokine gene polymorphisms on renal transplant clinical course and outcome have shown no influence, and probably other genes rather than IL-10 could be involved as key molecules for graft function