Optimization of Welding Input Parameters Using PSO Technique for Minimizing HAZ Width in GMAW

In order to conceive command systems for welding equipment based on intelligence techniques similar to human thinking; it is better to use artificial intelligence methods, for example: Genetic algorithms and particle swarm optimization. Freshly, this latter has received increased attention in many research fields. This paper discuss the application of particle swarm optimization algorithm to optimize the welding process parameters and obtain a better Width of Head Affected Zone (WHAZ) in the welding machine which is gas metal arc welding. The effect of four main welding variables in the gas metal arc welding process, namely welding speed, welding voltage, nozzle-to-plate distance and wire feed speed on the WHAZ are studied. A source code is developed in MATLAB 8.3 to perform the optimization

Improved PSO with Disturbance Term for Solving ORPD Problem in Power Systems

The essential purpose of an energy sys- tem is to provide electricity to its loads effectively and economically, as well as safely and reliably. Therefore, the solutions to the problems of Optimal Power Flow (OPF) and Optimal Reactive Power Dispatch (ORPD) to enable the efficient employment of various energy distributions should be found. Our work focuses on the ORPD issue; it can be formulated as a non-linear con- straint and with single or multiple objectives optimiza- tion problems. Minimizing total losses is one of the main objective functions to solve the ORPD problem. This paper presents the use of an improved particle swarm optimization -with a disturbance term- (called PSO-DT) algorithm, to find the solution of ORPD in the standard IEEE 30-bus power system for reduc- ing electrical power transmission losses. The obtained results demonstrate that the proposed method is more efficient and has a more extraordinary ability to get better solutions compared to the basic PSO method

On efficient models for model checking message-passing distributed protocols

The complexity of distributed algorithms, such as state machine replication, motivates the use of formal methods to assist correctness verification. The design of the formal model of an algorithm directly affects the efficiency of the analysis. Therefore, it is desirable that this model does not add "unnecessary" complexity to the analysis. In this paper, we consider a general message-passing (MP) model of distributed algorithms and compare different ways of modeling the message traffic. We prove that the different MP models are equivalent with respect to the common properties of distributed algorithms. Therefore, one can select the model which is best suited for the applied verification technique. We consider MP models which differ regarding whether (1) the event of message delivery can be interleaved with other events and (2) a computation event must consume all messages that have been delivered after the last computation event of the same process. For generalized MP distributed protocols and especially focusing on fault-tolerance, we show that our proposed model (without interleaved delivery events and with relaxed semantics of computation events) is significantly more efficient for explicit state model checking. For example, the model size of the Paxos algorithm is 1/13 th that of existing equivalent MP models. © 2010 Springer-Verlag

Evaluation of muscle strength and quality in North African patients with chronic hepatitis B: A pilot case control study

ABSTRACTEarly detection of alteration of muscle strength, quantity, and quality, and sarcopenia is useful in non-cirrhotic chronic hepatitis B (NC-CHB) patients. Studies, which explored the handgrip strength (HGS) are scarce with questionable results, and no previous case-control study explored the presence of sarcopenia.The aim of this study was to assess the muscle strength [i.e.; HGS absolute (HGSA), HGSA/body mass index (BMI)], muscle quantity [i.e.; appendicular skeletal muscle (ASM), ASM/height2, ASM/total body weight (TBW), ASM/BMI], and muscle quality [i.e.; HGSA/total muscle mass (TMM), HGSA/ASM] of NC-CHB patients.This was a case-control study. Cases (n = 26) were untreated NC-CHB patients, and controls (n = 28) were ‘apparently’ healthy participants. Muscle mass was estimated via the TMM (kg) and ASM (kg). Muscle strength was evaluated via the HGS data [i.e.; HGSA (kg), HGSA/BMI (m2)]. Six variants of HGSA were determined: highest values for the dominant and non-dominant hands, highest value between the two hands, averages of the three measurements for the two hands, and the average of the highest values of the two hands. Muscle quantity was expressed in three relative variants (ASM/height2, ASM/TBW, and ASM/BMI). Muscle quality was evaluated via relative HGS data adjusted by muscle mass (i.e.; HGSA/TMM, HGSA/ASM). Probable and confirmed sarcopenia were retained in front of low muscle strength, and low muscle strength and muscle quantity or quality, respectively.There were no significant differences between controls and NC-CHB patients in values of muscle i) Strength whatever the HGS’ mode of expression (e.g.; HGSA/BMI: 1.59 ± 0.54 vs. 1.53 ± 0.54 m2, p = 0.622, respectively), ii) Quantity (e.g.; ASM/BMI: 0.79 ± 0.24 vs. 0.77 ± 0.23 m2, p = 0.883), and iii) Quality (e.g.; HGSA/ASM: 2.00 ± 0.25 vs. 2.01 ± 0.41, p = 0.952, respectively). One NC-CHB participant had a confirmed sarcopenia.To conclude, both controls and NC-CHB patients had similar HGS values. Only one NC-CHB patient had a confirmed sarcopenia

A case report of abdominal wall hydatidosis: An uncommon location

Liver hydatid cyst fistulized in the abdominal wall is rare. The clinical symptoms were often misleading. It often poses a problem of seat diagnosis rather than a problem of its hydatid nature despite the great contribution of modern imagery. We reported this uncommon case to highlight the difficulties of preoperative diagnosis and a better operative approach. 46-year-old men consulted for right flank pain. The clinical exam revealed a right flank subcutaneous mass. An abdominal CT scan showed multicystic lesions on the right flank. The MRI showed multiple cystic lesions on the right flank with several endophytic and exophytic daughter cysts. The patient was operated on. A wide excision was adopted to remove all the cystic lesions. The postoperative follow-up was uneventful. Abdominal subcutaneous hydatid cysts cause a diagnostic problem and the treatment is controversial. Surgery remains the only curative treatment. It avoids the risk of complications such the fistula, infection, and rupture

A Reduction Theorem for Randomized Distributed Algorithms Under Weak Adversaries

International audienceWeak adversaries are a way to model the uncertainty due to asynchrony in randomized distributed algorithms. They are a standard notion in correctness proofs for distributed algorithms, and express the property that the adversary (scheduler), which has to decide which messages to deliver to which process, has no means of inferring the outcome of random choices, and the content of the messages. In this paper, we introduce a model for randomized distributed algorithms that allows us to formalize the notion of weak adversaries. It applies to randomized distributed algorithms that proceed in rounds and are tolerant to process failures. For this wide class of algorithms, we prove that for verification purposes, the class of weak adversaries can be restricted to simple ones, so-called round-rigid adversaries, that keep the processes tightly synchronized. As recently a verification method for round-rigid adversaries has been introduced, our new reduction theorem paves the way to the parameterized verification of randomized distributed algorithms under the more realistic weak adversaries

Formal Verification of Consensus Algorithms Tolerating Malicious Faults

Abstract. Consensus is the paradigmatic problem in fault-tolerant distributed computing: it requires network nodes that communicate by message passing to agree on common value even in the presence of (benign or malicious) faults. Several algorithms for solving Consensus exist, but few of them have been rigorously verified, much less so formally. The Heard-Of model proposes a simple, unifying framework for defining distributed algorithms in the presence of communication faults. Algorithms proceed in communication-closed rounds, and assumptions on the faults tolerated by the algorithm are stated abstractly in the form of communication predicates. Extending previous work on the case of benign faults, our approach relies on the fact that properties such as Consensus can be verified over a coarse-grained, round-based representation of executions. We have encoded the Heard-Of model in the interactive proof assistant Isabelle/HOL and have used this encoding to formally verify three Consensus algorithms based on synchronous and asynchronous assumptions. Our proofs give some new insights into the correctness of the algorithms, in particular with respect to transient faults.