An approach for solving multi-objective assignment problem with interval parameters
, Available Online, July 31
Kayvan Salehi PDF (296 K)
Abstract: This paper presents a multi-objective assignment problem (MAP) with interval parameters. Here, the model concentrates on three criteria: total cost, total profit and total operation time of assignment. The proposed model is classified as a nonlinear programming, in which it is difficult to solve. Hence, the model is converted into crisp linear programming problem by applying a substitution variables approach. In addition, a weighted min-max method is applied to transform the multi-objective problem into a single objective optimization problem. Finally, several numerical examples are provided to illustrate the implementation of the proposed approach. The results clearly provide some evidences that the proposed approach was easier to contrast compared with other approaches. The results also indicate that decision makers’ preferences over various objectives could influence on solutions.
Keywords: Assignment problem, Interval number, Weighted min-max method, Integer programming
The impact of leadership styles on organizational culture in Mapsa company
, Available Online, July 29
Dariush Gholamzadeh, Azadeh Tahvildar Khazaneh and Manijeh Salimi Nabi PDF (296 K)
Abstract: This paper examines the effect of leadership styles on organizational culture by testing a hypothesized model. A quantitative survey using questionnaire was conducted among 93 employees from diverse work units of Mapsa Company in October 2012. They filled out multifactor leadership questionnaire and the Denison organizational culture survey. Results of structural equation modeling (SEM) showed that Transformational and Transactional leadership styles could positively influence on organizational culture. Laissez-fair leadership has a negative effect on organizational culture. In conclusion, transformational leadership style was recommended to balance all four traits of Denison’s organizational culture.
Keywords: Leadership Styles, Transformational Leadership, Transactional Leadership, Laissez-faire Leadership, Organizational Culture
Improved AODV route recovery in mobile ad-hoc networks using a genetic algorithm
, Available Online, July 18
Ahmad Maleki and Mehdi Sadeghzadeh PDF (296 K)
Abstract: An important issue in ad-hoc on-demand distance vector (AODV) routing protocols is route failure caused by node mobility in the MANETs. The AODV requires a new route discovery procedure whenever a route breaks and these frequent route discoveries increase transmission delays and routing overhead. The present study proposes a new method for AODVs using a genetic algorithm to improve the route recovery mechanism. When failure occurs in a route, the proposed method (GAAODV) makes decisions regarding the QOS parameter to select source or local repair. The task of the genetic algorithm is to find an appropriate combination of weights to optimize end-to-end delay. This paper evaluates the metrics of routing overhead, average end-to-end delay, and packet delivery ratio. Comparison of the new algorithm and AODV (RFC 3561) using a NS-2 simulator shows that GAAODV obtains better results for the QOS parameters.
Keywords: Mobile ad-hoc networks, AODV, Route recovery mechanisms, Genetic algorithm, NS-2 simulator
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