122,038 research outputs found
Getting rid of store-buffers in TSO analysis
No full textWe propose an approach for reducing the TSO reachability analysis of concurrent programs to their SC reachability analysis, under some conditions on the explored behaviors. First, we propose a linear code-to-code translation that takes as input a concurrent program P and produces a concurrent program P? such that, running P? under SC yields the same set of reachable (shared) states as running P under TSO with at most k context-switches for each thread, for a fixed k. Basically, we show that it is possible to use only O(k) additional copies of the shared variables of P as local variables to simulate the store buffers, even if they are unbounded. Furthermore, we show that our translation can be extended so that an unbounded number of context-switches is possible, under the condition that each write operation sent to the store buffer stays there for at most k context-switches of the thread. Experimental results show that bugs due to TSO can be detected with small bounds, using off-the-shelf SC analysis tools
Lazy TSO reachability
No full textS.267-282We address the problem of checking state reachability for programs running under Total Store Order (TSO). The problem has been shown to be decidable but the cost is prohibitive, namely non-primitive recursive. We propose here to give up completeness. Our contribution is a new algorithm for TSO reachability: it uses the standard SC semantics and introduces the TSO semantics lazily and only where needed. At the heart of our algorithm is an iterative refinement of the program of interest. If the program's goal state is SC-reachable, we are done. If the goal state is not SC-reachable, this may be due to the fact that SC underapproximates TSO. We employ a second algorithm that determines TSO computations which are infeasible under SC, and hence likely to lead to new states. We enrich the program to emulate, under SC, these TSO computations. Altogether, this yields an iterative under-approximation that we prove sound and complete for bug hunting, i.e., a semi-decision procedure halting for positive cases of reachability.We have implemented the procedure as an extension to the tool Trencher [1] and compared it to the Memorax [2] and CBMC [14] model checkers
I will if you will : towards sustainable consumption
No full textReport is summarised in 'I will if you will : towards sustainable consumption : a summary'.The Sustainable Consumption Roundtable (Great Britain), a joint initiative between the National Consumer Council and the Sustainable Development Commission, explored the challenge of UK consumption rates which, if reproduced globally, would require three planets' worth of resources. Globally we are already ‘living beyond our means’ to the tune of around 20%, despite the fact that a significant proportion of the world receive significantly less than their fair share.Publisher PD
ANALISIS DAN PERANCANGAN KATALOG PRODUK MOBIL PADA PT. ASTRA INTERNATIONAL TSO, TBK BERBASIS MULTIMEDIA
Get PDFANALISIS DAN PERANCANGAN KATALOG PRODUK MOBIL PADA PT. ASTRA INTERNATIONAL TSO, TBK BERBASIS MULTIMEDI
Role of the TSO in public information/debate openness, transparency
No full textLicensing of a nuclear facility in Finland includes Government resolution, construction and operating li-censes, and parliament approval. STUK is requested to give its opinion on acceptability from safety point of view. Then it needs assistance from its technical support organisations. In this role the TSO should not participate public debate. It should only "tell the facts" if asked by the customer. If the TSO needs to work for both the regulator and the utility the TSO must be able to demonstrate independence and impar-tiality. There are, however, opportunities for the TSO to inform the public on general level, e.g., if it conducts research in various energy sectors and is well established. It can publish background informa-tion for layman on different types of phenomena, opportunities, threats, future views etc. The paper dis-cusses the TSO's public role mainly based on the experience of cooperation between VTT and STUK
Verification Techniques for TSO-Relaxed Programs
Get PDFKnowing the extent to which we rely on technology one may think that correct programs are nowadays the norm. Unfortunately, this is far from the truth. Luckily, possible reasons why program correctness is difficult often come hand in hand with some solutions. Consider concurrent program correctness under Sequential Consistency (SC). Under SC, instructions of each program's concurrent component are executed atomically and in order. By using logic to represent correctness specifications, model checking provides a successful solution to concurrent program verification under SC. Alas, SC’s atomicity assumptions do not reflect the reality of hardware architectures. Total Store Order (TSO) is a less common memory model implemented in SPARC and in Intel x86 multiprocessors that relaxes the SC constraints. While the architecturally de-atomized execution of stores under TSO speeds up program execution, it also complicates program verification. To be precise, due to TSO’s unbounded store buffers, a program’s semantics under TSO might be infinite. This, for example, turns reachability under SC (a PSPACE-complete task) into a non-primitive-recursive-complete problem under TSO. This thesis develops verification techniques targeting TSO-relaxed programs. To be precise, we present under- and over-approximating heuristics for checking reachability in TSO-relaxed programs as well as state-reducing methods for speeding up such heuristics. In a first contribution, we propose an algorithm to check reachability of TSO-relaxed programs lazily. The under-approximating refinement algorithm uses auxiliary variables to simulate TSO’s buffers along instruction sequences suggested by an oracle. The oracle’s deciding characteristic is that if it returns the empty sequence then the program’s SC- and TSO-reachable states are the same. Secondly, we propose several approaches to over-approximate TSO buffers. Combined in a refinement algorithm, these approaches can be used to determine safety with respect to TSO reachability for a large class of TSO-relaxed programs. On the more technical side, we prove that checking reachability is decidable when TSO buffers are approximated by multisets with tracked per address last-added-values. Finally, we analyze how the explored state space can be reduced when checking TSO and SC reachability. Intuitively, through the viewpoint of Shasha-and-Snir-like traces, we exploit the structure of program instructions to explain several state-space reducing methods including dynamic and cartesian partial order reduction
Some Ethical Ideals of the <i>Tso-chuan</i>
No full textIf the traditional opinion were correct which ascribes the Tso-chuan to Tso Ch'iu-ming, a contemporary of Confucius, his work would be of the utmost importance as a source of historical information, though even in that case we might well doubt whether all the incidents which it relates are genuinely historical and might wonder how many of the speeches in which it abounds were the composition of Tso Ch'iu-ming himself. If, on the other hand, those scholars are right who assign it to the Han dynasty, while of less importance as a record of fact, the Tso-chuan is still one of the most valuable of the works which have come down to us from Chinese antiquity, part of its significance on that supposition being that it illustrates what were believed at the time of its composition early in the Christian era to have been the ethical ideals which were acknowledged in the period to which Confucius himself belonged.</jats:p
Congestion management in coupled TSO and DSO networks
No full textThis paper proposes a three-stage coordination methodology to optimally manage congestion in day-ahead operation planning for Transmission Systems (TS) and Distribution Systems (DSs). The first stage provides the day-ahead model (DAM) results for the power units in the TS, and Energy Storage Systems (ESSs) and Electric Vehicles (EVs) in the DSs. The second stage applies the DAM results to the modelled TS to reveal any congestion issues. If congestion is depicted the need for congestion management (CM) by the Transmission System Operator (TSO) arises. Thus, the TSO performs an AC Optimal Power Flow (OPF) analysis, under power loss minimization, to provide the redispatch schedule in the TS and quantify the power transactions between TSO and the Distribution System Operators (DSOs). Finally, the DSOs examine if they can deliver these power transactions without congestion in their DSs, by applying AC OPF to minimize power losses. If this is not possible, then a relaxation scheme is applied to these power transactions in order to define the maximum DSO flexibility without congestion in the DS. The proposed methodology is applied to the simulated Greek TS and the results indicate that it can optimally redispatch the available assets with a coordinated interaction between TSO-DSO(s)
Involuntary Admissions, and Treatments (TSO) for Individuals Suffering from Schizophrenia: A Reflection on Patient Safety, and Quality of Care
Get PDF Introduction: Since the Italian Mental Health Act of 1978, public attention on the outcomes of Involuntary Hospital Treatment (TSO) for people struggling with Schizophrenia (SCZ) has increased. The practice is controversial because it goes against the Human Rights standards. Against this background, the author investigates factors linked to coercive measures, and personal experiences of acute care. He hypothesizes that limitation of freedom negatively affects the quality of the therapeutic relationship (TR). Materials, and Methods: Semi structured qualitative interviews (QIs) of individuals (n = 20) who were eligible for inclusion if the following criteria applied: [1] DSM-V diagnosis of Schizophrenia; [2] Having received at least one TSO; [3] Being outpatients; and [4] having emotional, and cognitional stability. The interview text was transcribed verbatim and analyzed by means of a phenomenological method. Results. The cohort described TSO as an unwelcome, and intrusive practice. Even if clinicians often justified the admissions, only a few patients gave an account of being told why their agency was eroded. Moreover, TSO damages Self-confidence, and trust in public services. Inasmuch, to prevent distress and avoid an outflow of so-called psychiatric refugees, the Italian government needs to improve joint crisis plans between patients, families, and medical equips. Discussion. The Republic of Italy does not have asylums but community-centers, and psychiatric wards within general hospitals. The Law No. 833 of 23 December 1978 established the possibility of a TSO for a period of 1-7 days in the simultaneous presence of [1] Psychiatric conditions that require urgent therapy; [2] Patient’s refusal of assistance; and [3] Circumstances that do not consent other less-invasive strategies. To author’s knowledge, this is one of the few qualitative reflections done on the pros and cons of adult Psychiatry, in Italy. The survey adds valuable information regarding degree, and predictors of loss of autonomy, dignity, and the possibility of interpersonal contact.
Keywords: Schizophrenia, TSO, Human Rights, Therapeutic Relationship, Law No. 833
TSO-DSO interface flow pricing: A bilevel study on efficiency and cost allocation
No full textIn the context of increasing distributed flexibility, enhanced TSO-DSO coordination is needed when procuring and activating flexibility. The literature shows that pricing the changes in the power flow over the TSO-DSO interfacing substation leads to optimal flexibility procurement cost in sequential TSO-DSO flexibility markets. This paper proposes a bilevel model, considering a TSO leader which sets interface flow prices freely, and DSO-followers in a Stackelberg game. This game-theoretical approach allows for the identification of regulatory risks and the testing of regulatory mechanisms. Based on two case studies, results show that, if left unregulated, the strategic TSO creates significant cost allocation distortions, creating unwanted financial transfers from DSOs to the TSO. However, when acting strategically, the TSO also activates (or leads to the activation of) economical flexibility providers, having as a reference the first-best option, namely the Common Coordination Scheme (CS). Leveraging on these results, a cap and floor mechanism is proposed, limiting unwanted cost allocation distortions and retaining incentives for efficient flexibility activations. Results showcase that a Fragmented CS with regulated interface flow prices could be an efficient second-best compared to the Common CS, outperforming other regulatory options found in the literature
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