Processing large scientific applications generates a huge amount of data, which makes running experiments in the cloud computing environment very expensive and energy-consuming. To find an optimal ...solution to the workflow scheduling problem, several approaches have been presented for scheduling workflow on cloud resources. However, more efficient approaches are needed to improve cloud service delivery. In this paper, an energy-efficient virtual machine mapping algorithm (EViMA) is proposed to improve resource management in the cloud computing environment to achieve effective scheduling that reduces cloud data center energy consumption, execution makespan, and execution cost. This ensures that the requirements of cloud users are met, and improves the quality of services offered by cloud providers. Our proposed mechanism considers the heterogeneity of scheduling from both cloud users’ and workflow applications’ perspectives. Through simulation experiments on real workflow datasets, the proposed EViMA can provide better solutions for both cloud users and cloud providers by reducing energy consumption, execution makespan, and execution cost better than the state-of-the-art.
Sharding is a promising solution to enhance the scalability of blockchain. However, previous sharding systems adopt the lock-based cross-shard protocol to exclusively handle one-shot cross-shard ...transactions, leading to low-efficiency executions and unavailable calls when handling complex cross-shard contracts that introduce multi-shot cross-shard transactions to invoke multiple contracts managed by different shards. In this paper, we aim to enable efficient execution of arbitrarily complex cross-shard contracts in blockchain sharding systems. First, we perform a calling-flow analysis on Ethereum contracts with more than 180 million real-world transactions and find that about <inline-formula><tex-math notation="LaTeX">30\%</tex-math> <mml:math><mml:mn>30</mml:mn><mml:mi mathvariant="normal">%</mml:mi></mml:math><inline-graphic xlink:href="zhang-ieq1-3365929.gif"/> </inline-formula> transactions invoke complex contracts. Then, motivated by the properties of these complex contracts, we propose an off-chain execution model, called ShardCon, to achieve efficient executions for complex cross-shard contracts by decoupling the contract execution from the cross-shard consensus. Next, we introduce a cross-shard contract execution engine and a contract-driven deployment rule to the overheads introduced by off-chain executions. Moreover, to adapt to the multi-chain property of a sharding system, we introduce an off-chain state atomic commit protocol. Finally, we implement a prototype and evaluate it with concrete cross-shard contracts, showing that ShardCon can achieve more than 10x increase in throughput and 2x decrease in confirmation latency than the state-of-the-art sharding systems.
Simple Temporal Networks (STNs) are a well-studied model for representing temporal constraints. They comprise a set of time-points (real-valued variables representing execution times) and binary ...difference constraints among them. Simple Temporal Networks with Uncertainty (STNUs) extend STNs in that some time-points (called contingent) are treated as exogenous variables, whose execution times, bound to fall within a given interval from the corresponding activation time-points (as specified by a “contingent link”), get revealed only during real-time execution. An STNU is dynamically controllable (DC) if there exists a strategy to execute its time-points satisfying all the constraints, regardless of the execution times of contingent time-points revealed during execution.
In this work we present a new system of constraint propagation rules for STNUs, which is sound-and-complete for DC checking. Our system comprises just three rules which, differently from the ones proposed in all previous works, only generate unconditioned constraints. In particular, after applying any of our rules, the network remains an STNU in all respects. Moreover, our completeness proof is short and non-algorithmic, based on the explicit construction of a valid execution strategy. This is a substantial simplification of the theory which underlies all the previous efficient algorithms for DC-checking.
Our analysis also shows: (1) the existence of late execution strategies for STNUs, (2) the equivalence of the notion of DC among several variants of the semantics of STNUs, (3) the existence of a fast algorithm for real-time execution of STNUs, which runs in O(KN) total time in a network with K≥1 contingent links and N≥K time points, considerably improving the previous O(N3)-time bound.
IoT-driven intelligent transportation systems (ITS) have great potential and capacity to make transportation systems efficient, safe, smart, reliable, and sustainable. The IoT provides the access and ...driving forces of seamlessly integrating transportation systems from the physical world to the virtual counterparts in the cyber world. In this paper, we present visions and works on integrating the artificial intelligent transportation systems and the real intelligent transportation systems to create and enhance "intelligence" of IoT-enabled ITS. With the increasing ubiquitous and deep sensing capacity of IoT-enabled ITS, we can quickly create artificial transportation systems equivalent to physical transportation systems in computers, and thus have parallel intelligent transportation systems, i.e. the real intelligent transportation systems and artificial intelligent transportation systems. The evolution process of transportation system is studied in the view of the parallel world. We can use a large number of long-term iterative simulation to predict and analyze the expected results of operations. Thus, truly effective and smart ITS can be planned, designed, built, operated and used. The foundation of the parallel intelligent transportation systems is based on the ACP theory, which is composed of artificial societies, computational experiments, and parallel execution. We also present some case studies to demonstrate the effectiveness of parallel transportation systems.
Modern processors use branch prediction and speculative execution to maximize performance. For example, if the destination of a branch depends on a memory value that is in the process of being read, ...CPUs will try to guess the destination and attempt to execute ahead. When the memory value finally arrives, the CPU either discards or commits the speculative computation. Speculative logic is unfaithful in how it executes, can access the victim's memory and registers, and can perform operations with measurable side effects. Spectre attacks involve inducing a victim to speculatively perform operations that would not occur during correct program execution and which leak the victim's confidential information via a side channel to the adversary. This paper describes practical attacks that combine methodology from side channel attacks, fault attacks, and return-oriented programming that can read arbitrary memory from the victim's process. More broadly, the paper shows that speculative execution implementations violate the security assumptions underpinning numerous software security mechanisms, including operating system process separation, containerization, just-in-time (JIT) compilation, and countermeasures to cache timing and side-channel attacks. These attacks represent a serious threat to actual systems since vulnerable speculative execution capabilities are found in microprocessors from Intel, AMD, and ARM that are used in billions of devices. While makeshift processor-specific countermeasures are possible in some cases, sound solutions will require fixes to processor designs as well as updates to instruction set architectures (ISAs) to give hardware architects and software developers a common understanding as to what computation state CPU implementations are (and are not) permitted to leak.
Recent transient execution attacks have demonstrated that attackers may leak sensitive information across security boundaries on a shared CPU core. Up until now, it seemed possible to prevent this by ...isolating potential victims and attackers on separate cores. In this paper, we show that the situation is more serious, as transient execution attacks can leak data across different cores on many modern Intel CPUs.We do so by investigating the behavior of x86 instructions, and in particular, we focus on complex microcoded instructions which perform offcore requests. Combined with transient execution vulnerabilities such as Micro-architectural Data Sampling (MDS), these operations can reveal internal CPU state. Using performance counters, we build a profiler, CROSSTALK, to examine the number and nature of such operations for many x86 instructions, and find that some instructions read data from a staging buffer which is shared between all CPU cores.To demonstrate the security impact of this behavior, we present the first cross-core attack using transient execution, showing that even the seemingly-innocuous CPUID instruction can be used by attackers to sample the entire staging buffer containing sensitive data - most importantly, output from the hardware random number generator (RNG) - across cores. We show that this can be exploited in practice to attack SGX enclaves running on a completely different core, where an attacker can control leakage using practical performance degradation attacks, and demonstrate that we can successfully determine enclave private keys. Since existing mitigations which rely on spatial or temporal partitioning are largely ineffective to prevent our proposed attack, we also discuss potential new mitigation techniques.
Industry 4.0 dictates the end of traditional centralized applications for production control. Its vision of ecosystems of smart factories with intelligent and autonomous shop-floor entities is ...inherently decentralized. Responding to customer demands for tailored products, these plants fueled by technology enablers such as 3D printing, Internet of Things, Cloud computing, Mobile Devices and Big Data, among others create a totally new environment. The manufacturing systems of the future, including manufacturing execution systems (MES) will have to be built to support this paradigm shift.
•We compared meta-analyses of movement imagery, observation, and execution.•Subcortical structures were most commonly associated with imagery and execution.•Conjunctions identified a consistent ...premotor-parietal-somatosensory network.•These data inform basic and translational work using imagery and observation.
Several models propose Motor Imagery, Action Observation, and Movement Execution recruit the same brain regions. There is, however, no quantitative synthesis of the literature that directly compares their respective networks. Here we summarized data from neuroimaging experiments examining Motor Imagery (303 experiments, 4902 participants), Action Observation (595 experiments, 11,032 participants), and related control tasks involving Movement Execution (142 experiments, 2302 participants). Comparisons across these networks showed that Motor Imagery and Action Observation recruited similar premotor-parietal cortical networks. However, while Motor Imagery recruited a similar subcortical network to Movement Execution, Action Observation did not consistently recruit any subcortical areas. These data quantify and amend previous models of the similarities in the networks for Motor Imagery, Action Observation, and Movement Execution, while highlighting key differences in their recruitment of motor cortex, parietal cortex, and subcortical structures.
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