Yagiz Onat Yazir

Dynamic Resource Allocation in Computing Clouds Using Distributed Multiple Criteria Decision Analysis

In computing clouds, it is desirable to avoid wasting resources as a result of under-utilization and to avoid lengthy response times as a result of over-utilization. In this paper, we propose a new approach for dynamic autonomous resource management in computing clouds. The main contribution of this work is two-fold. First, we adopt a distributed architecture where resource management is decomposed into independent tasks, each of which is performed by Autonomous Node Agents that are tightly coupled with the physical machines in a data center. Second, the Autonomous Node Agents carry out configurations in parallel through Multiple Criteria Decision Analysis using the PROMETHEE method. Simulation results show that the proposed approach is promising in terms of scalability, feasibility and flexibility.

Maitland: Lighter-Weight VM Introspection to Support Cyber-security in the Cloud

Despite defensive advances, malicious software (malware) remains an ever present cyber-security threat. Cloud environments are far from malware immune, in that: i) they innately support the execution of remotely supplied code, and ii) escaping their virtual machine (VM) confines has proven relatively easy to achieve in practice. The growing interest in clouds by industries and governments is also creating a core need to be able to formally address cloud security and privacy issues. VM introspection provides one of the core cyber-security tools for analyzing the run-time behaviors of code. Traditionally, introspection approaches have required close integration with the underlying hypervisors and substantial re-engineering when OS updates and patches are applied. Such heavy-weight introspection techniques, therefore, are too invasive to fit well within modern commercial clouds. Instead, lighter-weight introspection techniques are required that provide the same levels of within-VM observability but without the tight hypervisor and OS patch-level integration. This work introduces Maitland as a prototype proof-of-concept implementation a lighter-weight introspection tool, which exploits paravirtualization to meet these end-goals. The work assesses Maitlands performance, highlights its use to perform packer-independent malware detection, and assesses whether, with further optimizations, Maitland could provide a viable approach for introspection in commercial clouds.

Tradeoffs in cross platform solutions for mobile assistive technology

With the increasing popularity and wide penetration of mobile smart devices, the advanced capabilities of mobile phones and tablets are being incorporated into assistive technologies. These technologies are crucial for assisting the elderly and people with disabilities in order for them to live independently. There are a myriad ways of designing and developing mobile assistive applications today, each comes with its pros and cons. In this paper we investigate the tradeoffs to be considered when trying to build a “one-size-fits-all” cross platform solution to the existing assistive technology. We outline the design decisions with respect to cross-platform issues, performance, development costs, maintenance overhead, and so on. These design and implementation decisions are the outcome of our two prototype implementations: (i) the development of a cross-mobile application that helps users effectively navigate the outdoor public transit system; and (ii) the development of an application that monitors a users movement and detects certain abnormal behaviors such as falling. We also further investigate the system level concerns such as the performance and efficiency of data storage. We found that it is still challenging to develop a truly “one-size-fits-all” application with todays mobile techniques. However, this is an important first step towards platform independence of assistive technologies.

Adaptive routing in mobile ad hoc networks based on decision aid approach

In this paper, we propose a new approach to the problem of adaptive routing in small scale Mobile Ad Hoc Networks (MANET). The proposed approach focuses on leveraging the already existing routing algorithms in real-time through switching from one routing algorithm to another as the conditions change. The contribution of this work is three-fold: (1) nodes use a Multiple Criteria Decision Analysis method called PROMETHEE to make local decisions, (2) the final decision is evaluated as an aggregation of all the local decisions in the MANET through weighted voting, and (3) the network-wide decision process is carried out through a hybrid method that aims to benefit from the advantages of centralized and distributed methods, while limiting their disadvantages. The analyses based on the results extracted from simulations underline that the proposed approach produces stable configurations with minimal interruptions. Furthermore, the completion of global adaptation cycles are performed an order of magnitude faster in comparison to the results outlined in the previous work. These results indicate that the proposed solution is a promising alternative to the existing solutions, and forms a strong basis for further research on larger scale MANETs.

Beyond user interfaces in mobile accessibility: Not just skin deep

With the increasing popularity of mobile technologies, users today are able to access information from virtually anywhere. Examples include localization via the Global Positioning System (GPS), Internet access through cellular and WiFi networks, etc. Using assistive technologies, people with disabilities can live more independently than ever before. However, most of the current mobile applications are not developed with accessibility in mind. This paper uses mobile applications for public transit systems as a case study, and presents an extension of our prototype ABLE (Accessible Bussing through Location Estimation) Transit. Based on an estimate of the users current location, ABLE Transit leverages the location services on mobile devices and public transit information to reveal schedule and route information in accessible formats. We derive four groups of personas that need to be addressed when designing accessible software. While the cross platform accessibility is preserved at the user interface level, we further investigated system level concerns and implemented two data storage strategies for large transit schedule data. We identify the tradeoffs of Web versus native applications, local versus remote data storage when developing assistive technology, and discovered that accessibility at system level is particularly challenging.

Big file protocol (BFP): A traffic shaping approach for efficient transport of large files

Telecommunication networks are under stress due to rapid traffic increase. Since most of this traffic increase is due to large file transfers, this paper proposes a cross-layer transport protocol specifically designed to efficiently handle large transactions. Traffic generated from large transactions is shaped into a periodic succession of fixed-size data frames. Each transaction is then scheduled for transmission using a two-way reservation protocol. Simulation results show that the proposed approach is capable of significantly improving goodput and end-to-end delay relative to TCP, improving efficiency of bandwidth utilization by over 40%.

RPC automation: making legacy code relevant

Due to the well-known issues with Remote Procedure Calls (RPC), the rather simple idea of modifying legacy applications - that have low spatial locality to the data they need to process - to execute all of their procedures via RPC is not a feasible option. A more realistic and feasible alternative is to provide a self-management mechanism that can dynamically monitor and alter the execution of an existing application by selectively modifying certain procedures to execute remotely when it is necessary to improve spatial locality. In this paper we describe the motivations behind such a self-management mechanism, and outline an initial design. In addition, we introduce our vision for the required profiling component of these applications. As such, we introduce the Automated Legacy system Remote Procedure Call mechanism (ALRPC). It automatically converts existing monolithic C applications into a distributed system semi-automatically. Thus automation is a key criterion for successfully competing with existing remote procedure tools for legacy applications and with newer solutions such as SOAP and REST [12], [21]. ALRPC is the core component to convert monolithic applications into distributable self-adaptive RPC systems. The empirical results collected from our initial experiments show that our mechanisms level of automation outperforms existing industry strength tools and improves development time. At the same time our mechanism is able to correctly function with a significant code base and shows acceptable performance in initial tests.

Autonomous Resource Consolidation Management in Clouds Using IMPROMPTU Extensions

This paper focuses on the problem of resource consolidation management within cloud computing environments and extends our previous IMPROMPTU model which demonstrated the viability of distributed Multiple Criteria Decision Analysis (MCDA) to provide a resource consolidation management that simultaneously achieves lower numbers of reconfiguration events and fewer service level agreement (SLA) violations as compared to other approaches. A core limitation of our previous work was that it only assessed the PROMETHEE II outranking-based MCDA method, leaving open the question of whether better outranking schemes exist and, more generally, what denotes the properties of good outranking approaches for this problem domain. This work addresses these deficiencies through extending the IMPROMPTU model to directly compare PROMETHEE II with ELECRE III and PAMSSEM II, two other well-known outranking-based MCDA schemes. An in-depth analysis of the generated simulation results are then used to highlight the core trade-offs between each of these MCDA approaches.

Visual Assessment of Cloud Resource Consolidation Managers Using Convex Hulls

One way of simplifying the process of analyzing the performance of resource consolidation managers is to provide methods that can facilitate forming an initial understanding of their general characteristics before proceeding with further statistical evaluations. However, to the best of our knowledge, no such methods were previously proposed in the literature. In this work, we present a visualization tool that fills this gap by applying concepts from computational geometry in a rather unconventional manner. In the proposed method, the performance of a resource consolidation manager is represented using shells of convex hulls on a 2-dimensional plane, which can then be used to generate a preliminary understanding of various methods. We have been using the proposed method in our recent studies on the design, implementation and assessment of resource consolidation management methods. In our experience with the proposed tool, visual representations based on convex hulls prove to be of valuable assistance in providing quick and easy preliminary performance analyses which can later be used to direct the focus of statistical evaluations.

A low-cost realistic testbed for mobile ad hoc networks

Theoretical frameworks and simulation environments are proven to be very useful in evaluating conventional wired settings. However, due to the inclusion of various deficiency parameters which naturally exist in wireless channels modelling the communication behaviour in MANETs become much more complex. To overcome these major problems and create a realistic test platform for MANET research, we propose the use of inexpensive OLPC XO laptops that provide by default a Linux-based open source operating system, multi-hop mesh networking capabilities and a configurable wireless adapter. We believe that a design based on this hardware can substantially reduce the cost and time spent during the implementation and deployment of MANET testbeds and help researchers to focus on the systems to be deployed rather than the testbed itself.