Reproducibility and validity of an extensive semiquantitative food frequency questionnaire among Greek school teachers

The involvement of mental health professionals in determinations of dangerousness is both common and controversial. Among the various contexts for these evaluations, the release of potentially violent forensic patients from maximum security facilities evokes justified concern from involved experts and apprehension to outrage from the immediate community. We sought to examine how conclusions are reached on dangerousness at two sequential stages: clinical recommendations and Manifest Dangerousness Hearings decisions. In an archival study of 245 patients, we found that lack of progress in the institution and physical assaultiveness were the strongest correlates with dangerousness. In contrast, experts and review boards appeared to be relatively less influenced by diagnosis, types of treatment, and sociodemographic variables.     

Toward auto-scheduling compilers

In this paper we propose a general framework for compiling, scheduling, and executing parallel programs on parallel computers. We discuss important aspects of program partitioning, scheduling, and execution, and consider possible realistic alternatives for each issue. Subsequently we propose a possible implementation of an auto-scheduling compiler and give simple examples to illustrate the principles. Our approach to the entire problem is to utilize program information available to the compiler while, at the same time, allowing for run-time corrections and flexibility.This work was supported in part by the National Science Foundation under Grant NSF MIP-8410110, the U.S. Department of Energy under Grant DE-FG02-85ER25001, an IBM donation and a grant from AT&T.     

Architectural and compiler techniques for energy reduction inhigh-performance microprocessors

In this paper, we focus on low-power design techniques for high-performance processors at the architectural and compiler levels. We focus mainly on developing methods for reducing the energy dissipated in the on-chip caches. Energy dissipated in caches represents a substantial portion in the energy budget of today's processors. Extrapolating current trends, this portion is likely to increase in the near future, since the devices devoted to the caches occupy an increasingly larger percentage of the total area of the chip. We propose a method that uses an additional minicache located between the I-Cache and the central processing unit (CPU) core and buffers instructions that are nested within loops and are continuously otherwise fetched from the I-Cache. This mechanism is combined with code modifications, through the compiler, that greatly simplify the required hardware, eliminate unnecessary instruction fetching, and consequently reduce signal switching activity and the dissipated energy. We show that the additional cache, dubbed L-Cache, is much smaller and simpler than the I-Cache when the compiler assumes the role of allocating instructions to it. Through simulation, we show that for the SPECfp95 benchmarks, the I-Cache remains disabled most of the time, and the “cheaper” extra cache is used instead. We also propose different techniques that are better adapted to nonnumeric nonloop-intensive code     

Computational network federations: a middleware architecture for network-based computing

Computational Network Federations (CNFs) enable an arbitrary set of heterogeneous hosts which are connected via any type of network to form dynamic virtual distributed systems that cooperate to execute an application, or serve as generalized application service platforms to end users. CNFs motivate a view of the Internet as a vast unified host: a repository of information, application services, and an omnipresent supercomputing resource regardless of the type of access device or access methodology. CNFs provide a powerful way of virtualizing generalized enterprise networks (or even the Internet), and an economic and resilient model for deploying enterprise applications, (such as CRM) and peer-2-peer services (e.g., chatrooms). This paper describes a middleware architecture that enables network-based computing, communications, and services through a unified, access, and platform-independent approach. CNFs borrow from the capabilities of grid computing and aim toward intelligent computational service networks that are ubiquitous, secure, and adaptive to user and access-method idiosyncrasies. CNFs encompass a set of abstractions and interfaces that provide: 1) a unified service-oriented view of the network to the user; 2) a homogeneous host abstraction to applications; and 3) a shared-memory abstraction to software developers. This paper outlines the architecture of CNFs and describes in more detail i-DVM, a distributed multithreaded meta-OS that forms the core of a CNF and implements the virtual machine abstraction and location transparency.     

Automatic extraction of functional parallelism from ordinaryprograms

Presents the hierarchical task graph (HTG) as an intermediate parallel program representation which encapsulates minimal data and control dependences, and which can be used for the extraction and exploitation of functional, or task-level parallelism. The hierarchical nature of the HTG facilitates efficient task-granularity control during code generation, and thus applicability to a variety of parallel architectures. The construction of the HTG at a given hierarchy level, the derivation of the execution conditions of tasks which maximizes task-level parallelism, and the optimization of these conditions which results in reducing synchronization overhead imposed by data and control dependences are emphasized. Algorithms for the formation of tasks and their execution conditions based on data and control dependence constraints are presented. The issue of optimization of such conditions is discussed, and optimization algorithms are proposed. The HTG is used as the intermediate representation of parallel Fortran and C programs for generating parallel source as well as parallel machine code     

Microwave-induced auditory effect in a dielectric sphere

The acoustic pressure wave generation inside an electromagnetically lossy dielectric sphere from an incident microwave pulse is analyzed rigorously. The pressure wave equation derived using the first-order approximation of a thorough formulation on microwave-induced thermoacoustic effect in dielectrics, is used. The inhomogeneous hyperbolic-type pressure wave differential equation is solved by a Green's function theory approach. The boundary conditions on the dielectric sphere-air interface are taken into account. The power is computed by applying the exact Mie theory solution for the dielectric sphere. Two types of acoustic waves are derived inside the sphere: (a) a transient burst type pressure wave, corresponding to the free-space contribution of Green's function; and (b) an infinite set of damped oscillations related to the normal acoustic modes of the spherical resonator. Numerical results are computed and presented for several cases     

The hierarchical task graph as a universal intermediate representation

This paper presents an intermediate program representation called the Hierarchical Task Graph (HTG), and argues that it is not only suitable as the basis for program optimization and code generation, but it fully encapsulates program parallelism at all levels of granularity. As such, the HTG can be used as the basis for a variety of restructuring and optimization techniques, and hence as the target for front-end compilers as well as the input to source and code generators. Our implementation and testing of the HTG in the Parafrase-2 compiler has demonstrated its suitability and versatility as a potentially universal intermediate representation. In addition to encapsulating semantic information, data and control dependences, the HTG provides more information vital to efficient code generation and optimizations related to parallel code generation. In particular, we introduce the notion of precedence between nodes of the structure whose grain size can range from atomic operations to entire subprograms. This work was supported in part by the National Science Foundation under Grant No. NSF-CCR-89-57310, the U. S. Department of Energy under Grant No. DOE-DE-FG02-85ER25001, and a grant from Texas Instruments Inc.     

A Cross-Layer Analysis of Session Setup Delay in IP Multimedia Subsystem (IMS) With EV-DO Wireless Transmission

This paper analyzes the session setup delay in the IP multimedia subsystem (IMS) with the CDMA2000 evolution data only rev. A (EV-DO rev. A) standard for wireless transmission. Session setup delay is particularly critical for interactive multimedia applications, such as gaming, push-to-X and voice over IP (VoIP), as it directly translates in user perception of service quality. Keeping signaling delay low, however, is a challenge in IMS due to the text-based nature of the session initiation protocol (SIP) for signaling, and, more significantly, due to the lossy and capacity constrained wireless links. To address this challenge, we analyze the session setup delay end-to-end, by taking into account key system properties across all layers, ranging from radio links to IMS signaling architecture. We present a model for cross-layer performance analysis and simulation, which includes the statistical properties of the EV-DO (rev. A) wireless channel, and also takes into consideration the properties of transport protocols (TCP, UDP) and SIP signaling (message size and compression). By means of analysis and simulations, we study the setup delay performance of a generic, multi-operator IMS communication scenario between two mobile users. We describe how session setup delay can be estimated and reduced in realistic IMS settings and we propose architecture alternatives to the basic IMS scenario. The results derived from this study show that the proposed methods can incrementally lead to a lower setup delay and less sensitivity to the radio transmission quality and frame error rate compared to the base IMS scenario     

An algorithm for the evaluation of radar propagation in thespherical Earth diffraction region

An efficient method for the accurate computation of the Airy function is presented. This method is applied to the calculation of the propagation factor for diffraction around a smooth sphere. These calculations give accurate results well into the visible region. even for high-altitude antennas, extending the useful range of the SEKE low-altitude radar propagation computer model