Process Migration

We used the carbon isotope ratios of hydrocarbons and CO 2 , and the proportions of noble gas isotopes of associated gases from several geological provinces of the Potiguar Basin (Brazil) for gas/source rock correlation, and to determine maturity, post-genetic processes (migration, leakage, biodegradation), and to assess the possible interactions between hydrocarbons and surrounding waters. Barriers of permeability at the basin scale, the amount of water interacting with the accumulated hydrocarbons, proportion of meteoric water, and contamination of the fluids by the mantle were quantified for the distinct petroleum systems defined in this basin. Four hydrocarbon provinces have been defined in the Potiguar Basin. The first is located in the southern part of the basin, and the other three are in the northern part, with offshore pods of generation; migration occurred along NEeSW horst and grabben structures. All gases are mainly thermogenic (d 13 C of methane between À49 and À34, except for biodegraded gases with isotopically lighter methane), generated in the oil window, and only two fields from one of the trends seem to have been significantly biodegraded (d 13 C of propane up to À5.8 per mil). The source rocks were lacustrine for the gases from the southwest of the basin, and mixed marine/lacustrine for two trends. The third trend, as well as an offshore field, appears to have a lacustrine source rock, and the hydrocarbon generation and accumulation are older than for the other fields. Each of the three trends is generally isolated in terms of fluid migration, except in one location where noble gas isotopes indicate that the Guamaré Trend is invaded by fluids of the Macau Trend. An important contamination by mantle fluids has been confirmed for all the hydrocarbon fields close to the shore ( 3 He/ 4 He ratios up to 1.6 times the atmospheric ratio). The mantle contribution (as high as 20% of total helium) decreases inland. The mantle contribution provides some chronological constraints for the hydrocarbon accumulations, and may have had an influence in hydrocarbon generation, due to an igneous activity-associated influence in the hydrocarbon generation pod.

A metasystem allows seamless access to a collection of distributed computational resources. Checkpointing is an important service in high throughput computing, especially for process migration and recovery after system crash. This article describes the experiences on incorporating checkpointing and recovery facilities in a Java-based metasystem. Our case study is suma, a metasystem for execution of Java bytecode, both sequential and parallel. This paper also shows preliminary results on checkpointing and recovery overhead for single-node applications.

The core of Cloud computing includes virtualization of hardware resources such as storage, network and memory provided through virtual machines (VM). The live migration of these VMs is introduced to obtain multiple benefits which mainly include high availability, hardware maintenance, fault takeover and workload balancing. Besides various facilities of the VM migration, it is susceptible to severe security risks during migration process due to which the industry is hesitant to accept it. The research done so far is on the performance of migration process; whereas the security aspects in migration are not fully explored. We have carried out an extensive survey to investigate the vulnerabilities, threats and possible attacks on the live VM migration. Furthermore, we have identified security requirements for secure VM migration and presented a detailed analysis of existing solutions on the basis of these security requirements. Finally, limitations in the existing solutions are presente...

Virtualization technology reduces cloud operational cost by increasing cloud resource utilization level. The incorporation of virtualization within cloud data centers can severely degrade cloud performance if not properly managed. Virtual machine (VM) migration is a method that assists cloud service providers to efficiently manage cloud resources while eliminating the need of human supervision. VM migration methodology migrates current-hosted workload from one server to another by either employing live or non-live migration pattern. In comparison to non-live migration, live migration does not suspend application services prior to VM migration process. VM migration enables cloud operators to achieve various resource management goals, such as, green computing, load balancing, fault management, and real time server maintenance. In this paper, we have thoroughly surveyed VM migration methods and applications. We have briefly discussed VM migration applications. Some open research issues...

INDICE ARTICULOS R.ESEfiAS VOLUMEN VII/No. 13 J7JNlO Ec@N@MlA MAXIMO VEGA-CENTENO B. Pobreza, niveles y patrones de consumo: un anáIisis a través de los países latinoamericanos 9 ADOLFO FIGUEROA. Educación y productividdd en la economía campesina de América Latina DANIEL COTLEAR W. Empleo urbano y migraciones internas en el Per4 OSCAR DANCOURT. Devaluación y saiario real AI,BERTO ESPEJO 0. El empleo en el Perú: un nuevo enfoque de Francisco Verdera; LUCIA ROMERO B. Politica económica y agricultura en el Perú 1969-1979 de Elena Alvarez 131 -EMPLEOURBANOY MICRACIONESINTE~INAS ENELPERU* I. Infroduccidn DANIEL COTLEAR W.** Parece haber un consensp seflalando que uno de los problemas principales del Perú contempordneo es el "problema del empleo", y en este consenso participan tanto acadbmicos como periodistas y funcionarios del Gobierno. El consenso se extiende afiiando que la agudeza del problema del empleo en la actualidad estit asociado con la crisis económica. Asf por ejemplo, Schydlowsky y Wicht al comentar sobre los efectos de la crisis actual seftalan que "El resultado mtls dramático (. . .) es el desempleo masivo y creciente de la fuena laboral, abn en el sector industrial . . .l Sin embargo, como muestran los datos de Schydlowsky y Wicht el impacto de la crisis económica consistió en elevar en 7 por ciento el subempleo y desempleo de 1978 con respecto al de 1975. Si el impacto de la crisis fue incrementar el problema del empleo en 7 por ciento, la solución de la crisis reducirá el desempieo a una magnitud similar a la de 1975. iPero en 1975 el 47 por ciento de la fuerza laboral estaba snbempleada o desemplea-* Este trabajo es "subproducto" de una revisión de la Bibliograffa sobre migraciones realizada dentro del marco de una investfgacíón ffnancinda por la Asodacf6n Multfdfsdplbrarfa para la Investfgadón y Docenba en Población (ÁMIDEP) y quiero agradecer allf tanto a la institucfón como a Carlos Jirdacochea sulen brindó eitfmulo Y buen humor.

Interactive systems with registers and voices (shortly, rvsystems) are a model for interactive computing obtained closing register machines with respect to a space-time duality transformation ("voices" are the time-dual counterparts of "registers"). In the same vain, AGAPIA v0.1, a structured programming language for rv-systems, is the spacetime dual closure of classical while programs (over a specific type of data). Typical AGAPIA programs describe open processes located at various sites and having their temporal windows of adequate reaction to the environment. The language naturally supports process migration, structured interaction, and deployment of components on heterogeneous machines. In this paper a sound Hoare-like spatio-temporal logic for the verification of AGAPIA v0.1 programs is introduced. As a case study, a formal verification proof of a popular distributed termination detection protocol is presented.

3-Monochloropropane-1,2-diol (3-MCPD) is the most common chemical contaminant of the group of chloropropanols. It can occur in foods and food ingredients at low levels as a result of processing, migration from packaging materials during storage and domestic cooking. A sensitive method for determination of 3-MCPD in foodstuffs using programmable temperature vaporization (PTV) with large-volume injection (LVI) gas chromatography (GC) with tandem mass spectrometry detection (MS/MS) has been developed and optimized. The optimization of the injection and detection parameters was carried out using statistical experimental design. A Plackett-Burman design was used to estimate the influence of resonance excitation voltage (REV), isolation time (IT), excitation time (ET), ion source temperature (IST), and electron energy (EE) on the analytical response in the ion trap mass spectrometer (ITMS). Only REV was found to have a statically significant effect. On the other hand, a central composite design was used to optimize the settings of injection temperature (T inlet), vaporization temperature (T vap), vaporization time (t vap) and flow (Flow). The optimized method has an instrumental limit of detection (signal-to-noise ratio 3:1) of 0.044 ng mL −1. From Valencian, Spain, supermarkets 94 samples of foods were surveyed for 3-MCPD. Using the optimized method levels higher than the limit established for soy sauce by the European Union were found in some samples. The estimated daily intake of 3-MCPD throughout the investigated foodstuffs for adults and children was found about 0.005 and 0.01%, respectively, of the established provisional tolerable daily intake.

Considerable research and development has been invested in software Distributed Shared Memory (DSM). The primary focus of this work has traditionally been on high performance and consistency protocols. Unfortunately, clusters present a number of challenges for any DSM systems not solvable through consistency protocols alone. These challenges relate to the ability of DSM systems to adjust to load fluctuations, computers being added/removed from the cluster, to deal with faults, and the ability to use DSM objects larger than the available physical memory. This paper introduces the Synergy DSM System and its integration with the virtual memory, group communication and process migration services of the Genesis Cluster Operating System.

Parallelism management is a difficult task, in particular in parallel systems based on clusters (of PCs or workstations). We claim in this paper that parallelism management should be provided by an operating system that inherits many features of a distributed operating system and provides new services that address the needs of parallel processes, cluster's resources, and application programmers. This system, in order to allow parallel programs to achieve high performance, transparency and ease of use, should provide services such as establishment of a virtual machine; mapping processes to computers; concurrent process creation and process duplication supported by process migration; computation co-ordination; group communication; and distributed shared memory. In order to substantiate the claim the first version of a cluster operating system managing parallelism, called GENESIS, has been developed and presented in this paper. The results of the execution of some parallel applications, that further substantiate our claim, are shown.

Considerable research and development has been invested in software Distributed Shared Memory (DSM). The primary focus of this work has traditionally been on high performance and consistency protocols. Unfortunately, clusters present a number of challenges for any DSM systems not solvable through consistency protocols alone. These challenges relate to the ability of DSM systems to adjust to load fluctuations, computers being added/removed from the cluster, to deal with faults, and the ability to use DSM objects larger than the available physical memory. This paper introduces the Synergy DSM System and its integration with the virtual memory, group communication and process migration services of the Genesis Cluster Operating System.

This report describes an implementation of MPI-1 on the GENESIS cluster operating system and compares this implementation to a UNIX based MPI implementation. The changes that were made to the implementation are compared between the two, and the advantages of porting to GENESIS are detailed. This report demonstrates how GENESIS' load balancing supported by process migration improves the execution performance of an MPI application. The significance of this report is in demonstrating how these services can enhance parallel programming tools to improve performance and how future parallel programming tool design could take advantage of these services.

The core of Cloud computing includes virtualization of hardware resources such as storage, network and memory provided through virtual machines (VM). The live migration of these VMs is introduced to obtain multiple benefits which mainly include high availability, hardware maintenance, fault takeover and workload balancing. Besides various facilities of the VM migration, it is susceptible to severe security risks during migration process due to which the industry is hesitant to accept it. The research done so far is on the performance of migration process; whereas the security aspects in migration are not fully explored. We have carried out an extensive survey to investigate the vulnerabilities, threats and possible attacks on the live VM migration. Furthermore, we have identified security requirements for secure VM migration and presented a detailed analysis of existing solutions on the basis of these security requirements. Finally, limitations in the existing solutions are presented.

The core of Cloud computing includes virtualization of hardware resources such as storage, network and memory provided through virtual machines (VM). The live migration of these VMs is introduced to obtain multiple benefits which mainly include high availability, hardware maintenance, fault takeover and workload balancing. Besides various facilities of the VM migration, it is susceptible to severe security risks during migration process due to which the industry is hesitant to accept it. The research done so far is on the performance of migration process; whereas the security aspects in migration are not fully explored. We have carried out an extensive survey to investigate the vulnerabilities, threats and possible attacks on the live VM migration. Furthermore, we have identified security requirements for secure VM migration and presented a detailed analysis of existing solutions on the basis of these security requirements. Finally, limitations in the existing solutions are presente...

This paper describes a system that enables parallel programs written using the BSPlib communications library to migrate processes among a network of workstations. Not only does the system provide fault tolerance of BSPlib jobs, but by utilising a load manager that maintains an approximation of the global load of the system, it is possible to continually schedule the migration of BSP processes onto the least loaded machines in a network. Results are provided for an industrial electromagnetics application that show that we can achieve similar throughput on a publically available collection of workstations as a dedicated NOW.

This paper reviews the field of process migration by summarizing the key concepts and giving an overview of a high level process migration algorithm and also provides a unique alternative implementation of our own for the linux environment. Design and implementation issues of process migration are analyzed in general, and these are used as pointers in describing our implementation. The primary aim of this paper is to build a user space process migration tool which would obviate the need for kernel support. This paper aims to provide an insight into the difficult task of actual migration for performance gain.

This paper reviews the field of process migration by summarizing the key concepts and giving an overview of a high level process migration algorithm and also provides a unique alternative implementation of our own for the linux environment. Design and imple-mentation issues ...

A very important issue in distributed systems is the management of load among system nodes. Load balancing enables a better use of the system resource capabilities and a better performance by allocating nodes that are more suitable for the execution of some tasks. This work proposes a multi-agent load balancing architecture for distributed object applications denominated MALBA which uses artificial neural networks and a set of policies to support the process of migrating and replicating the application objects. MALBA architecture outlines a decentralized balancing process which balances the load among nodes which execute a distributed object application.

Multitasking and multiuser operating system's performance depends on the efficiency of scheduling algorithm. Most commonly used Round Robin scheduling algorithm may not give optimal result if the burst time of processes is very high as compared to the time quantum of Round Robin algorithm. In this case, context switching and turnaround time of processes is very high. In this paper, a two queue based Round Robin Scheduling Algorithm is proposed. In the proposed approach two queues are used. One queue is exclusively used for CPU intensive processes and other queue is used for I/O intensive processes. This reduces the waiting time and turnaround time when there are less or equal numbers of I/O intensive processes. Performance Analysis depending upon CPU intensive and I/O intensive processes shows that it provides better results.

We describe a type system for the Xdπ calculus [9]. An Xdπ-network is a network of locations, where each location consists of both a data tree (which contains scripts and pointers to nodes in trees at different locations) and a process, for modelling process interaction, process migration and interaction between processes and data. Our type system is based on types for locations, data and processes, expressing security levels. A tree can store data of different security level, independently from the security level of the enclosing location. The access and mobility rights of a process depend on the security level of the "source" location of the process itself, i.e. of the location where the process was in the initial network or where the process was created by the activation of a script. The type system enjoys type preservation under reduction (subject reduction). In consequence of subject reduction we prove the following security properties. In a well-typed Xdπ-network, a process P whose source location is of level h can copy data of security level at most h and update data of security level less than h. Moreover, the process P can only communicate data and go to locations of security level equal or less than h.

A current trend in high-performance computing is the use of large-scale computing grids. These platforms consist of geographically distributed cluster federations gathering thousands of nodes. At this scale, node and network failures are no more exceptions, but belong to the normal system behavior. Thus, grid applications must tolerate failures and their evaluation should take reaction to failures into account. The failures of distributed computing system can be divided into three categories: node crash, network failure and process fault. The fault tolerance is a significant and complex issue in grid computing systems. Various techniques have been investigated to detect and tolerate faults in distributed computing systems. We propose, in this paper, a decentralized model of fault tolerance based on dynamic colored graphs. From this model, we show through some experiments, the benefits of colored graphs to manage failures in grids.

Complexity and heterogeneity of the deployed software applications often result in a wide range of dynamic states at runtime. The corner cases of software failure during execution often slip through the traditional software checking. If the software checking infrastructure supports the transparent checkpoint and resume of the live application states, the checking system can preserve and replay the live states in which the software failures occur. We introduce a novel software checking framework that enables application states including program behaviors and execution contexts to be cloned and resumed on a computing cloud. It employs (1) EXPLODE’s model checking engine for a lightweight and general purpose software checking (2) ZAP system for faster, low overhead and transparent checkpoint and resume mechanism through virtualized PODs (PrOcess Domains), which is a collection of host-independent processes, and (3) scalable and distributed checking infrastructure based on Distributed E...

This study presents a practical solution for data collection and restoration to migrate a process written in high‐level stack‐based languages such as C and Fortran over a network of heterogeneous computers. We first introduce a logical data model, namely the Memory Space Representation (MSR) model, to recognize complex data structures in process address space. Then, novel methods are developed to incorporate the MSR model into a process, and to collect and restore data efficiently. We have implemented prototype software and performed experiments on different programs. Experimental and analytical results show that: (1) a user‐level process can be migrated across different computing platforms; (2) semantic information of data structures in the process's memory space can be correctly collected and restored; (3) costs of data collection and restoration depend on the complexity of the MSR graph in the memory space and the amount of data involved; and (4) the implantation of the MSR m...

We consider policies for CPU load balancing in networks of workstations. We address the question of whether preemptive migration (migrating active processes) is necessary, or whether remote execution (migrating processes only at the time of birth) is sufficient for load balancing. We show that resolving this issue is strongly tied to understanding the process lifetime distribution. Our measurements indicate that the distribution of lifetimes for a UNIX process is Pareto (heavy-tailed), with a consistent functional form over a variety of workloads. We show how to apply this distribution to derive a preemptive migration policy that requires no hand-tuned parameters. We used a trace-driven simulation to show that our preemptive migration strategy is far more effective than remote execution, even when the memory transfer cost is high.

Future high-performance computing systems may face frequent failures with their rapid increase in scale and complexity. Resilience to faults has become a major challenge for large-scale applications running on supercomputers, which demands fault tolerance support for prevalent MPI applications. Among failure scenarios, process failures are one of the most severe issues as they usually lead to termination of applications. However, the widely used MPI implementations do not provide mechanisms for fault tolerance. We propose FTA-MPI (Fault Tolerance Assistant MPI), a programming model that provides support for failure detection, failure notification and recovery. Specifically, FTA-MPI exploits a try/catch model that enables failure localization and transparent recovery of process failures in MPI applications. We demonstrate FTA-MPI with synthetic applications and a molecular dynamics code CoMD, and show that FTA-MPI provides high programmability for users and enables convenient and flexible recovery of process failures.

Optimal utilization of cluster computing is partly dependent upon pre-emptive process migration. However, this migration involves a host of issues, one of them being the transfer of system-dependent resources. We focus on the overhead incurred by migrated processes using sockets. We then describe a solution that we devised and implemented to avoid this overhead through the use of 'migratable sockets'. Our studies show that the use of 'migratable sockets' considerably improves the execution time of a process using sockets as compared to the execution time of a process that uses standard sockets and thus bears the communication overhead.

Checkpointing is an important method for providing fault tolerance, load balancing, process migration, periodic backup, and many other functions [9], [14]. It is also the basic tool used in CAPE [1], [2], a paradigm which aims at distributing the execution of a program on a distributed-memory environment. This paper presents the new approach to checkpointer and the original optimization on checkpoint structure we have implemented and evaluated to make incremental checkpointing more efficient and more appropriate, especially for CAPE.

Checkpointing is an important method for providing fault tolerance, load balancing, process migration, periodic backup, and many other functions [9], [14]. It is also the basic tool used in CAPE [1], [2], a paradigm which aims at distributing the execution of a program on a distributed-memory environment. This paper presents the new approach to checkpointer and the original optimization on checkpoint structure we have implemented and evaluated to make incremental checkpointing more efficient and more appropriate, especially for CAPE.

Checkpointing Rollback Recovery protocol is often used to provide fault tolerance for real-time applications. However, existing checkpointing implementations support only non-real-time applications as the checkpointing overhead is usually not deterministic. In this paper, we present an implementation of the checkpointing scheme with the Real-Time Application Interface (RTAI) supported by Linux, where services provided by the real-time operating system makes the checkpointing overhead, including the time to place a checkpoint and the time to recover the system from a failure, predictable.

Even though the cloud platform promises to be reliable, several availability incidents prove that it is not. How can we be sure that a parallel application finishes it´s execution even if a site is affected by a failure? This paper presents H-RADIC, an approach based on RADIC architecture, that executes parallel applications protected by RADIC in at least 3 different virtual clusters or sites. The execution state of each site is saved periodically in another site and it is recovered in case of failure. The paper details the configuration of the architecture and the experiment´s results using 3 clusters running NAS parallel applications protected with DMTCP, a very well-known distributed multi-threaded checkpoint tool. Our experiments show that by adding a cluster protector it will be possible to implement the next level in the hierarchy, where the first level in the RADIC hierarchy works as an observer at a site level. In adition, the experiments showed that the protection implement...

Adaptive load distribution is necessary for parallel applications to co-exist e ectively with other jobs in a network of shared, heterogeneous workstations. We present three methods that provide such support for PVM applications. Two of these methods, MPVM and UPVM, adapt to changes in the workstation environment by transparently migrating the virtual processors (VPs) of the parallel application. A V P i n MPVM is a Unix process, while UPVM de nes lightweight, process-like VPs. The third method, ADM, is a p r ogramming methodology for writing programs that perform adaptive load distribution through data movement. These methods are discussed and compared i n terms of e ectiveness, usability, and performance.

Ever since 2005, there has been an intensification in the outflows of Portuguese nationals, characterized by the transformation in the institutional context in which they occur, the emergence new destination countries, and the simultaneous resurgence of flows to traditional destinations. This article, applying data gathered from France and the UK, enhances the comprehension of contemporary Portuguese intra-EU migratory flows. It shows how this emigration is characterized by continuities and discontinuities with previous flows and by similarities and dissimilarities in the socio demographic characteristics of emigrants and their migratory paths and strategies. One proportion of these flows emerges as qualitatively different from past economic migration flows as regards both migrant demographic features and their migration processes. We may ascribe another proportion to the traditional economic migration framework that has enabled migrants to extend their opportunity structure beyond the national context in response to the obstructions experienced within national borders.

We present a communication library to improve performance of PVM. The new library introduces communication primitives based on Active Messages. We propose a hybrid scheme that includes a signal driven message noti cation scheme plus controlled polling. The new communication library is tested along with the normal PVM library to assess the improvement in performance.

As modern hardware becomes increasingly complex, it becomes more difficult to create efficient software for common computing workloads. One way to manage this complexity is to employ holistic solutions that consider multiple layers of hardware and software in conjunction, allowing software to adapt and react to changing conditions at run time. This paper focuses on lightweight modifications to commodity hardware that enable virtual execution environments to help solve problems in the areas of power, reliability, security, and performance. We present our experimental simulation framework, which enables us to explore the design space of hardware/software collaboration, and we demonstrate its ability to produce simplified, reactive solutions to two emerging computing problems. First, we improve heterogeneous process migration with hardware feedback, and second, we use hardware information to respond to voltage emergencies (di/dt) in software. These symbiotic design approaches illustrate the simple nature yet significant potential of cross-layer, reactive solutions.

In an optimistic parallel simulation, logical processes (Ips) proceed with their computation without any constraints. However, if the computing requirements of different lps are not balanced or if the processors are not homogeneous, some lps may lag behind in simulation time while others surge forward. In other words, if the simulation clocks of different lps are not progressing at the same rate, cascading rollbacks may occur nullifying the potential benefit of an optimistic parallel discrete event simulation (PDES). Hence it is necessary to balance the computational load on different lps in such a way that their local simulation clocks advance almost at the same rate. In this paper, we propose two algorithms for dynamic load balancing which reduce the number of rollbacks in an optimistic PDES system. Our first algorithm is based on the load transfer mechanism between lps; while the second algorithm, based on the principle of evolutionary strategy, migrates logical processes between...

The mobile agent has been seen as a promising distributed computing technology. The mobility characteristic of mobile agent makes it to travel often in open network. In this scenario, it is obvious that the mobile agents are vulnerable to various security threats. Protecting free-roaming mobile agents from malicious host and from other mobile agents has drawn much attention in recent years. The protection of mobile agents is considered as one of the greatest challenges of security, because the platform of execution has access to all the components of the mobile agent. In this paper, we present a new architecture paradigm of mobile agents, which allows the separation of the implementation tasks of the agent and its security mechanisms. Our approach is based on using two strategies of adaptation to adapt the mobile agent security at runtime, depending on the sensitivity of the services required to perform the duties of the agent and the degree of confidence of the visited platforms.

Single-chip multiprocessors and multiple-thread architectures are becoming an affordable solution for high-performance general-purpose workstations and servers. On these machines, the workload is typically constituted of both sequential and parallel applications. Shared-bus shared-memory multithreaded multiprocessor can be used to speed-up the execution of such workload. In this environment, the scheduler takes care of the load balancing by allocating a ready process on the first available processor, thus producing process migration. Process migration and the persistence of private data into different caches produce an undesired sharing, named passive sharing. The copies due to passive sharing produce useless coherence traffic on the bus and coping with such a problem may represent a challenging design problem for these machines. Many protocols use smart solutions to limit the overhead to maintain coherence among shared copies. None of these studies treats passive-sharing directly, although some indirect effect is present while dealing with the other kinds of sharing. Affinity scheduling can alleviate this problem, but this technique does not adapt to all load conditions, especially when the effects of migration are massive. A simple coherence protocol is presented. This protocol eliminates passive sharing using information from the compiler that is normally available in operating system kernels. The performance of this protocol has been evaluated and compared against other solutions proposed in the literature by means of enhanced trace-driven simulation. The performance of the proposed dolution outperforms the other protocols, especially in the case of a multithreaded processor, thus demonstrating its effectiveness in this kind of hardware platform. The complexity of the proposed approach has been evaluated in terms of the number of protocol states, additional bus lines and required software support. The protocol further limits the coherence-maintaining overhead by using information about access patterns to shared data exhibited in parallel applications.

A orla costeira do Estado do Rio de Janeiro, de Maricá a Campos, incluindo a turística Região dos Lagos, vem sofrendo há muito tempo grande impacto devido a interesses antagônicos: especulação imobiliária versus proteção da biodiversidade. Toda essa área abriga manguezais, um frágil ecossistema berço da vida marinha. Intimamente associadas aos manguezais, as restingas costeiras são constituídas por um conjunto de micro-ecossistemas onde se encontra uma vegetação típica. Apesar disso, poucos estudos foram realizados visando o conhecimento da diversidade química dessa vegetação. Neste trabalho, pretendemos resgatar trabalhos fitoquímicos e etnofarmacológicos pioneiros desenvolvidos primeiro na restinga de Maricá e, posteriormente, na restinga do Parque Nacional de Jurubatiba, apontando alguns dados recentes com vistas a usos econômicos potenciais. É apresentado um levantamento dos metabólitos secundários encontrados no gênero Clusia e das atividades farmacológicas e ecológicas associa...

In this article, we present a simulator for cache memory systems on symmetric multiprocessors. This simulator is called SMPCache. It has a full graphic and user-friendly interface, and it operates on PC systems with Windows. The simulator has been conceived as a tool for the teaching of cache memories on multiprocessors systems. This tool is very useful to evaluate and understand different design alternatives: the number of processors, the cache coherence protocols, schemes for bus arbitration, mapping, replacement policies, cache size, memory block size, etc. Our experiences in the last three years have demonstrated to us the bene®ts of the simulator for teaching purposes.

In a combinatorial auction, there has a server, some agents, and some jobs which can be used to reach efficient resource and job allocations among the agents. In our paper, we have shown how any server can achieve maximum throughput as well as maximum profit based on some server constraints where each agent has one or more skills to perform those jobs on a priority basis which can be executed in a whole or partial. This algorithm can effectively distribute the appropriate job allocation among skilled agents with proper acknowledgment to the server after a certain period.

In virtualized servers, with live migration technique pages are copied from one physical machine to another while the virtual machine (VM) is running. The dynamic migration of virtual machines encumbers the data center which in turn reduces the performance of applications running on that particular physical machine. A considerable number of studies have been carried out in the area of performance evaluation during live VM migration.  However, all the aspects related to the migration process have not been examined for the performance assessment. In this paper, we propose a novel approach to evaluate the performance during migration process in different types of coupled machine environment. It is presented here that the state of art VM migration technology requires further improvement in realizing effective migration by monitoring comprehensive performance value. We introduced the parameter, θ, to compare performance value which can be used for controlling and halting unsuccessful mig...

This paper proposes a new adaptable FPGA logic element based on fracturable 6-LUTs, which fundamentally alters the longstanding belief that a 4-LUT is the most efficient area/delay tradeoff. We will describe theory and benchmarking results showing a 15% performance increase with 12% area decrease vs. a standard BLE4. The ALM structure is one of a number of architectural improvements giving Altera's 90nm Stratix II architecture a 50% performance advantage over its 130nm Stratix predecessor.

Ever since 2005, there has been an intensification in the outflows of Portuguese nationals, characterized by the transformation in the institutional context in which they occur, the emergence new destination countries, and the simultaneous resurgence of flows to traditional destinations. This article, applying data gathered from France and the UK, enhances the comprehension of contemporary Portuguese intra-EU migratory flows. It shows how this emigration is characterized by continuities and discontinuities with previous flows and by similarities and dissimilarities in the socio demographic characteristics of emigrants and their migratory paths and strategies. One proportion of these flows emerges as qualitatively different from past economic migration flows as regards both migrant demographic features and their migration processes. We may ascribe another proportion to the traditional economic migration framework that has enabled migrants to extend their opportunity structure beyond the national context in response to the obstructions experienced within national borders.

Given paper contain proposed approached for task scheduling which is done on a group of computers. Analysis of process data part by dividing them into number of fixed part & merge into single set that as good as previous original data set. Parallelism an approach for doing jobs in amount of time i.e very fast. The paper contain dynamic approach for process migration using thread level paradigm. Creating a thread of process into number of task, that leads to reduce total execution time of process. An algorithm is used to calculate PCB for decision purpose to achieve load balancing. Fair share approach is considered to allocating task to every processor using preemption strategy. The MPI[4] [10]is used for process communication. This system has defined to reduce total execution time on onboard & between board times. Open knoppix & MOSIX platform(Middleware) are used to show the results. Prime number calculation code is used to show parallel architecture like SIMD computer. Cluster com...

Given paper contain proposed approached for task scheduling which is done on a group of computers. Analysis of process data part by dividing them into number of fixed part & merge into single set that as good as previous original data set. Parallelism an approach for doing jobs in amount of time i.e very fast. The paper contain dynamic approach for process migration using thread level paradigm. Creating a thread of process into number of task, that leads to reduce total execution time of process. An algorithm is used to calculate PCB for decision purpose to achieve load balancing. Fair share approach is considered to allocating task to every processor using preemption strategy. The MPI[4] [10]is used for process communication. This system has defined to reduce total execution time on onboard & between board times. Open knoppix & MOSIX platform(Middleware) are used to show the results. Prime number calculation code is used to show parallel architecture like SIMD computer. Cluster com...

Given paper contain proposed approached for task scheduling to achieve load balancing which is done on a group of computers. The processor idles due to large set of data, on the multiprocessor computer. Consideration of process data part by dividing them into number of fixed part & merge into single set that as good as previous original data set. Parallelism an approach for doing jobs in amount of time i.e. very fast. The paper contains dynamic approach for process migration using thread level paradigm. Creating a thread of process into number of task, that leads to reduce total execution time of process. An algorithm is used to calculate PCB for decision purpose to achieve load balancing. We are taking CPU and MEMORY parameter in this approach. Fair share approach is considered to allocating task to every processor using preemption strategy. The MPI is used for process communication. This system has defined to reduce total execution time on onboard & between board times. Open knopp...

Given paper contain proposed approached for task scheduling to achieve load balancing which is done on a group of computers. Consideration of process data part by dividing them into number of fixed part & merge into single set that as good as previous original data set. Parallelism an approach for doing jobs in amount of time i.e. very fast. The paper contains dynamic approach for process migration using thread level paradigm. Creating a thread of process into number of task, that leads to reduce total execution time of process. An algorithm is used to calculate PCB for decision purpose to achieve load balancing. We are taking CPU and MEMORY parameter in this approach. Fair share approach is considered to allocating task to every processor using preemption strategy. The MPI is used for process communication. This system has defined to reduce total execution time on onboard & between board times. Open knoppix & MOSIX platform (Middleware) are used to show the results. Prime number calculation code is used to show parallel architecture like SIMD computer. Cluster computing is way of resource managing & scheduling strategy.

Providing a distributed cooperative environment is a challenging task, which requires a middleware infrastructure that provides, among others, management of distributed shared data, synchronization, consistency, recovery, security and privacy support. In this paper, we present the ECADeG project which proposes a layered architecture for developing distributed cooperative environments running on top of a desktop grid middleware that can encompass multiple organizations. We also present a particular cooperative environment for supporting scientific research focused at the health domain which uses the services supplied by the ECADeG architecture in order to allow researchers to share access to multiple institutions databases, visualize and analyze data by means of data mining techniques, edit research documents cooperatively, exchange information through forums and chats, etc.. Such a rich cooperative environment helps thus the establishment of partnerships between health care professionals and their institutions.

In a combinatorial auction, there has a server, some agents, and some jobs which can be used to reach efficient resource and job allocations among the agents. In our paper, we have shown how any server can achieve maximum throughput as well as maximum profit based on some server constraints where each agent has one or more skills to perform those jobs on a priority basis which can be executed in a whole or partial. This algorithm can effectively distribute the appropriate job allocation among skilled agents with proper acknowledgment to the server after a certain period.