YARV: yet another RubyVM

Object-oriented scripting languages like Javascript and Python are popular partly because of their dynamic features. These include the runtime modification of objects and classes through addition of fields or updating of methods. These features make static typing difficult and so usually dynamic typing is used. Consequently, errors such as access to non-existent members are not detected until runtime.We first develop a formalism for an object based language, JS0 with features from Javascript, including dynamic addition of fields and updating of methods. We give an operational semantics and static type system for JS0using structural types. Our types allow objects to evolve in a controlled manner by classifying members as definite or potential.We define a type inference algorithm for JS0 that is sound with respect to the type system. If the type inference algorithm succeeds, then the program is typeable. Therefore, programmers can benefit from the safety offered by the type system, without the need to write explicitly types in their programs.

<p> Due to the great freedom in contemporary structural design, conventional design techniques cannot be applied to all spatial compositions and new materials. Widely available CAE software often tries to automate more common check methods found in (inter)national norms, but does not provide universal solutions. The complexity of modern structures, while economical and aesthetically appealing, requires that the engineer often write his/her own checks or perform manual calculations.</p><p> Design Forms (SDF) is a new software technology that enables the easy, on-the-fly writing of customised engineering algorithms and design checks by means of simplified programming. The application uses a C#-based, object-oriented scripting language, and is furnished with an intuitive UI, a full set of mathematical and logical operators, possibilities to include text and graphical descriptions, tables, charts and extensive reports. Built-in toolboxes with engineering formulae and libraries help the user-developer create standalone solutions that can be reused, shared, sold commercially, and linked to CAE software where advanced GUI and 3D visualisation possibilities may be used while pre- and post-processing. This paper presents the SDF tool and illustrates its use by means of practical examples of structural design and detailing.</p>

Dynamic segmentation is commonly viewed as one of the most effective aspects of GIS for transportation applications. To date, much of this effort has focused on relational data models, with object data models receiving far less attention. This paper presents an object model that provides a natural representation of dynamically segmented features by extending the Object Database Management Group (ODMG) standard with a special mechanism, called parametric polymorphism. This mechanism supports the shifting of a conventional data type into a linear type to maintain knowledge about events (e.g. pavement condition, traffic volumes and traffic accidents) that change spatially along linear features. An associated object query language unavailable in current GIS packages is also provided for data analyses relevant to dynamic segmentation. The model and query language have been implemented using an object-oriented scripting language in a GIS environment.

In this paper we present the design and implementation of the xorbac component that provides a flexible RBAC service. The xorbac, implementation conforms to level 4a of the unified NIST model for RBAC and can be reused for arbitrary applications on Unix or Windows with a C or Tcl linkage. xorbac runtime elements can be serialized and recreated from RDF data models conforming to a well-defined RDF schema. Furthermore we present our experiences with xorbac for the deployment within the HTTP environment for a web-based mobile code system.

Just-in-time (JIT) compilation during program execution and ahead-of-time (AOT) compilation during software installation are alternate techniques used by managed language virtual machines (VM) to generate optimized native code while simultaneously achieving binary code portability and high execution performance. Profile data collected by JIT compilers at run-time can enable profile-guided optimizations (PGO) to customize the generated native code to different program inputs. AOT compilation removes the speed and energy overhead of online profile collection and dynamic compilation, but may not be able to achieve the quality and performance of customized native code. The goal of this work is to investigate and quantify the implications of the AOT compilation model on the quality of the generated native code for current VMs. First, we quantify the quality of native code generated by the two compilation models for a state-of-the-art (HotSpot) Java VM. Second, we determine how the amount of profile data collected affects the quality of generated code. Third, we develop a mechanism to determine the accuracy or similarity for different profile data for a given program run, and investigate how the accuracy of profile data affects its ability to effectively guide PGOs. Finally, we categorize the profile data types in our VM and explore the contribution of each such category to performance.

Concurrency has been with us almost from the beginning of computing. Managing and programming for concurrency is a difficult problem and various solutions have been suggested over the years. Debates on message passing vs. remote procedure call, synchronous vs. asynchronous message passing, bounded vs. unbounded buffers, active vs. passive objects etc. still continue. No solution is entirely satisfactory. Concurrent programming usually depends heavily on the nature of the problem at hand and the architecture of the target machine.

With the rapid development of virtualization technology, virtual machine (VM) is widely used by cloud computing - the more and more popular computing paradigm. Thus, in order to guarantee the security of cloud computing, it is necessary to securely identify the kernel of VM, the software stack running on VM and the hardware platform which VM relies on. This paper designs a system of trusted connection based on virtual machine architecture and implements a system prototype. Our system not only can securely measure and identify the kernel of VM, the software stack running on VM and the hardware platform which VM relies on, but also can realize isolations to untrusted VMs. There are three main parts in our system: trusted chain, attestation and isolation. The experiments described in this paper prove that our system ensures trusted connection of VMs and achieves isolations to untrusted VMs. The performance of our system is also analyzed and evaluated. According to the analysis results, our system is practical in terms of performance.

Cloud computing systems are popular in computing industry for their ease of use and wide range of applications. These systems offer services that can be used over the Internet. Due to their wide popularity and usage, cloud computing systems and their services often face issues resource management related challenges. In this paper, we present v-Mapper, a resource consolidation scheme which implements network resource management concepts through software-defined networking (SDN) control features. The paper makes three major contributions: (1) We propose a virtual machine (VM) placement scheme that can effectively mitigate the VM placement issues for data-intensive applications; (2) We propose a validation scheme that will ensure that a cloud service is entertained only if there are sufficient resources available for its execution and (3) We present a scheduling policy that aims to eliminate network load constraints. We tested our scheme with other techniques in terms of average task processing time, service delay and bandwidth usage. Our results demonstrate that v-Mapper outperforms other techniques and delivers significant improvement in system’s performance.

The ubiquitous game platform implemented by our team is composed of a C++ compiler, a java translator, and a virtual machine. The EVM (Embedded Virtual Machine) is a stack-based solution that supports object-oriented languages such as C++ and java. It uses the SIL (Standard Intermediate Language) as an intermediate language, which consists of an operation code set for procedural and object-oriented languages. The existing C++ compilers are used to execute programs after translating them into a target machine code. The downside of this method is its low practicality, along with its platform-dependency. To resolve this matter, we developed a C++ compiler that generates virtual machine codes based on platform-independent stacks that are not target machine codes. This paper presents a decompiler system that converts a C++ compiler generated intermediate language, namely SIL, to a representation of a C++ program. This method optimizes the simulation needed for the generation of exacted SIL code, and a solution that can verify the SIL code generation through a C++ program represented in the decompiler. Furthermore, the ease of extracting the meaning of a program, as opposed to assembly-structured SIL codes, allows much more convenience in changing the software structure and correcting it to improve performance.

Embedded systems pose unique challenges to Java application developers and virtual machine designers. Chief among these challenges is the memory footprint of both the virtual machine and the applications that run within it. With the rapidly increasing set of features provided by the Java language, virtual machine designers are often forced to build custom implementations that make various tradeoffs between the footprint of the virtual machine and the subset of the Java language and class libraries that are supported. In this paper, we present the ExoVM, a system in which an application is initialized in a fully featured virtual machine, and then the code, data, and virtual machine features necessary to execute it are packaged into a binary image. Key to this process is feature analysis, a technique for computing the reachable code and data of a Java program and its implementation inside the VM simultaneously. The ExoVM reduces the need to develop customized embedded virtual machines by reusing a single VM infrastructure and automatically eliding the implementation of unused Java features on a per-program basis. We present a constraint-based instantiation of the analysis technique, an implementation in IBM's J9 Java VM, experiments evaluating our technique for the EEMBC benchmark suite, and some discussion of the individual costs of some of Java's features. Our evaluation shows that our system can reduce the non-heap memory allocation of the virtual machine by as much as 75%. We discuss VM and language design decisions that our work shows are important in targeting embedded systems, supporting the long-term goal of a common VM infrastructure spanning from motes to large servers.

Modern multi-core, multi-socket hardware powering the "cloud" is designed with memory and cache resources that have local associativity to a group of cores. Operating systems have characterized these associativities as part of Non-Uniform Memory Architecture (NUMA) optimizations within their virtual memory manager (VMM) and scheduler which improves application performance. Mature NUMA optimizations are prevalent for an OS running on bare-hardware. However, their benefits are reduced within virtual machines(VM) in the cloud. Even though cloud applications are executed by standard multi-core multi-socket hardware, the abstraction brought in by the virtualization layer makes it challenging to optimize resource management within a VM. This paper describes new paradigms in hypervisor technology-- scheduling VMs on cores and managing their memory resources which streamlines their execution on underlying multicore hardware. Being Linux kernel developers, we base our work on Linux operating system and Kernel Virtual Machine (KVM) --a subsystem which turns the Linux kernel into a scalable hypervisor. We evaluate few approaches for optimal resource allocation with KVM. We summarize our findings with a comparative study of how different scheduling algorithms can be employed with KVM for various systems to support efficient resource placement while running cloud workloads.

Resource management for cloud computing environments that are characterized by many layers emerges as a critical task for cloud computing providers. Such providers are compelled by the demands and strategies of stochastic customers to adopt dynamic resource management for the top-bottom scaling of the cloud resources on the basis of variable needs. Resource management in the infrastructure as a service layer relies on virtual machine (VM) characteristics, such as estimated VM classes. Given that a cloud provider offers a variety of VM classes that differ as regards the size of computing resources (e.g., central processing unit, memory, and input/output devices), optimizing cloud resources to maximize cloud revenue is a challenging dilemma. More specifically, the dynamic management of resources in cloud spot markets is confronted with various severe obstacles. In consideration of these issues, this study investigated a dynamic resource management model for cloud spot markets and put forward an efficient model that manages spare resources for the purpose of expanding cloud revenue. The model estimates the available spare capacity of a spot market, evaluates the maximum expected revenue of stagnant VMs on the basis estimated cumulative capacity, and locates the optimum VM combinations that bear complementary workloads and capacities and can coexist in a certain host. Our model also improves the understanding of cloud resource scaling and generates inferences that can be adopted in managing cloud resources for all layers as well as Reserved and On-Demand markets.

The article is devoted to the proposal of a new way to build a resource plan for ERP-system implementation projects, which has ease of use and speed of obtaining results, and this in turn allows you to flexibly emulate various situations. The method is applicable to corporate system implementation projects in which the software development is carried out. The proposed method uses the mechanism of the RICEF estimator, which is an expert assessment of the labor costs for preparing and developing programs for a pair of parameters «type of development – complexity». In the future, benchmarking is used, which determines the duration of the project phases in percentage terms. Based on the calculated efforts that define the stages of design and build, and the results of benchmarking, the timing of all remaining phases is calculated. The distribution of labor costs for the remaining stages of the project is carried out according to the pyramid principle, for which milestones of the analysis, integration testing and cutover are processed. The final plan of human resources is based on the calculated labor costs set for all stages of the project. Consequently, creation of the project schedule, determination of the scope of work for all phases, as well as finalization of the resource plan are carried out using only the planned labor costs of design and build stages.KeywordsResource planRICEFBenchmarkingPmbokCorporate information systemsERP-systems

R/sup 2/AD, a flexible robotics application development environment, combines powerful graphical display features with tools that support the rapid development of application programs. The graphical interface allows researchers to monitor the system state variables during the dynamic execution of robot programs. This feature enhances the researcher's efficiency in interpreting experimental results. Rapid development is supported by a virtual machine through the use of software engineering principles and object-oriented techniques. In addition to these features, the user is able to emulate a wide variety of robot computational paradigms. This allows experimentation with, and comparison of, various computational techniques (e.g., hierarchical versus heterarchical control process topologies). The utility of the R/sup 2/AD virtual machine is demonstrated through applications currently under development. >

Though the use of internet of things (IoT) technology is increasing, it is difficult to reuse application program once implemented because of various kinds of device and platform. In order to solve these problems, a method of using a virtual machine in an IoT device has been proposed. However, there is a disadvantage that the execution speed of the application program is very slow compared to the native code due to the characteristics of the virtual machine. Ahead-of-Time (AoT) compilation is a technique that precompiles bytecodes into native code to speed up execution of virtual machines. In this paper, we design the AoT compilation system for IoT-Cloud virtual machine system. The designed system is suitable for the convergence environment of the IoT and the cloud. Since only a portion of the bytecode is compiled into native code, the memory load of the virtual machine required for loading native code is reduced.