A Survey of Security and Privacy Challenges in Cloud Computing: Solutions and Future Directions

While cloud computing is gaining popularity, diverse security and privacy issues are emerging that hinder the rapid adoption of this new computing paradigm. And the development of defensive solutions is lagging behind. To ensure a secure and trustworthy cloud environment it is essential to identify the limitations of existing solutions and envision directions for future research. In this paper, we have surveyed critical security and privacy challenges in cloud computing, categorized diverse existing solutions, compared their strengths and limitations, and envisioned future research directions

A Catalog of Bad Smells in Design-by-Contract Methodologies with Java Modeling Language

Bad smells are usually related to program source code, arising from bad design and programming practices. Refactoring activities are often motivated by the detection of bad smells. With the increasing adoption of Design-by-Contract (DBC) methodologies in formal software development, evidence of bad design practices can similarly be found in programs that combine actual production code with interface contracts. These contracts can be written in languages, such as the Java Modeling Language (JML), an extension to the Java syntax. This paper presents a catalog of bad smells that appear during DBC practice, considering JML as the language for specifying contracts. These smells are described over JML constructs, although several can appear in other DBC languages. The catalog contains 6 DBC smells. We evaluate the recurrence of DBC smells in two ways: first by describing a small study with graduate student projects, and second by counting occurrences of smells in contracts from the JML models application programming interface (API). This API contains classes with more than 1,600 lines in contracts. Along with the documented smells, suggestions are provided for minimizing the impact or even removing a bad smell. It is believed that initiatives towards the cataloging of bad smells are useful for establishing good design practices in DBC

An efficient scheduling method for grid systems based on a hierarchical stochastic petri net

This paper addresses the problem of resource scheduling in a grid computing environment. One of the main goals of grid computing is to share system resources among geographically dispersed users, and schedule resource requests in an efficient manner. Grid computing resources are distributed, heterogeneous, dynamic, and autonomous, which makes resource scheduling a complex problem. This paper proposes a new approach to resource scheduling in grid computing environments, the hierarchical stochastic Petri net (HSPN). The HSPN optimizes grid resource sharing, by categorizing resource requests in three layers, where each layer has special functions for receiving subtasks from, and delivering data to, the layer above or below. We compare the HSPN performance with the Min-min and Max-min resource scheduling algorithms. Our results show that the HSPN performs better than Max-min, but slightly underperforms Min-min

Data-driven Adaptive Safety Monitoring using Virtual Subjects in Medical Cyber-Physical Systems: A Glucose Control Case Study

Medical cyber-physical systems (MCPS) integrate sensors, actuators, and software to improve patient safety and quality of healthcare. These systems introduce major challenges to safety analysis because the patient’s physiology is complex, nonlinear, unobservable, and uncertain. To cope with the challenge that unidentified physiological parameters may exhibit short-term variances in certain clinical scenarios, we propose a novel run-time predictive safety monitoring technique that leverages a maximal model coupled with online training of a computational virtual subject (CVS) set. The proposed monitor predicts safety-critical events at run-time using only clinically available measurements. We apply the technique to a surgical glucose control case study. Evaluation on retrospective real clinical data shows that the algorithm achieves 96% sensitivity with a low average false alarm rate of 0.5 false alarm per surgery

Addressing User Requirements in Open Source Software: The Role of Online Forums

User satisfaction has always been important in the success of software, regardless of whether it is closed and proprietary or open source software (OSS). OSS users are geographically distributed and include technical as well as novice users. However, it is generally believed that if OSS was more usable, its popularity would increase tremendously. Hence, users and their requirements need to be addressed in the priorities of an OSS environment. Online public forums are a major medium of communication for the OSS community. The research model of this work studies the relationship between user requirements in open source software and online public forums. To conduct this research, we used a dataset consisting of 100 open source software projects in different categories. The results show that online forums play a significant role in identifying user requirements and addressing their requests in open source software

A Hybrid Texture Coding Method for Fast Texture Mapping

An efficient texture compression method is proposed based on a block matching process between the current block and the previously encoded blocks. Texture mapping is widely used to improve the quality of rendering results in real-time applications. For fast texture mapping, it is important to find an optimal trade-off between compression efficiency and computational complexity. Low-complexity methods (e.g., ETC1 and DXT1) have often been adopted in real-time rendering applications because conventional compression methods (e.g., JPEG) achieve a high compression ratio at the cost of high complexity. We propose a block matching-based compression method that can achieve a higher compression ratio than ETC1 and DXT1 while maintaining computational complexity lower than that of JPEG. Through a comparison between the proposed method and existing compression methods, we confirm our expectations on the performance of the proposed method

Barriers and Enablers to Vocational IT Education: Responding to South Africa's ICT Skills Crisis

Advancement in digital technologies has directed the attention of developing countries toward ICT’s to aid socio-economic advancement. These technological solutions cannot be implemented as an island, and its effective use requires proportionate advancement in local ICT skills levels to ensure effective operation and sustainability. Increasingly demands for skilled ICT workforce globally is placing pressure on institutions to be more responsive, and to produce ICT graduates with a skillset that is more relevant and closer aligned to the needs of industries. In South Africa the ICT skills landscape remains an object of conflicting reports. Depending on who the question is posed to, the paradoxical views describe the country as either facing a critical shortfall of skilled ICT professionals, or that droves of qualified ICT professionals cannot find suitable employment. These contradictory notions suggest a possible mismatch between the current skills of ICT professionals, the supply of appropriately skilled ICT graduates by education institutions and industry demands for appropriately skilled ICT workforce. Attempts to reform the country’s skills landscape has resulted in numerous policy pronouncements and skills development strategies by the public and private sectors with limited success. This focus of this study was to evaluate the National Certificate Vocational Information Technology (NCV IT) strategy, an ICT skills development mandate issued to South African Technical and Vocational Education and Training (TVET) Colleges in response to the country’s ICT skills shortage. Using the Design-Reality Gap Model, the study evaluated the intended design objectives and current reality of NCV IT to gauge its status ten years post inception. While the South African government boasts increasing access to the programme, little focus is given to the handful of graduates who successfully complete the programme and even less who find meaningful employment. The study further operationalised the Design Reality Gap Model to demonstrate its applicability and value in the evaluation of Vocational Education and Training (VET) programmes. Primary data informing the study was from focus group discussions and semi-structured interviews with key NCV IT stakeholders. Secondary data supporting the study was collected by reviewing key documents relating to NCV IT. The findings reveal significant gaps exist between the programme’s intended design and current reality, indicative of the key challenges hindering the effective delivery of its ICT skills promise. It further positions the NCV IT programme as a post-apartheid dumping ground for financially disadvantaged and academically underperforming individuals hoping to achieve self-sufficiency. What was envisaged to be an enabler for the country’s ICT skills development has instead become a black hole for public funding yielding no return on investment. Recommendations were suggested along particular structural dimensions to improve the NCV IT programme, and the development of a more effective vocational ICT skills development strategy