Optimizing selection of competing features via feedback-directed evolutionary algorithms

Software that support various groups of customers usually require complicated configurations to attain different functionalities. To model the configuration options, feature model is proposed to capture the commonalities and competing variabilities of the product variants in software family or Software Product Line (SPL). A key challenge for deriving a new product is to find a set of features that do not have inconsistencies or conflicts, yet optimize multiple objectives (e.g., minimizing cost and maximizing number of features), which are often competing with each other. Existing works have attempted to make use of evolutionary algorithms (EAs) to address this problem. In this work, we incorporated a novel feedback-directed mechanism into existing EAs. Our empirical results have shown that our method has improved noticeably over all unguided version of EAs on the optimal feature selection. In particular, for case studies in SPLOT and LVAT repositories, the feedback-directed Indicator-Based EA (IBEA) has increased the number of correct solutions found by 72.33% and 75%, compared to unguided IBEA. In addition, by leveraging a pre-computed solution, we have found 34 sound solutions for Linux X86, which contains 6888 features, in less than 40 seconds.No Full Tex

Characteristics of Traffic Flow at Nonsignalized T-Shaped Intersection with U-Turn Movements

Most nonsignalized T-shaped intersections permit U-turn movements, which make the traffic conditions of intersection complex. In this paper, a new cellular automaton (CA) model is proposed to characterize the traffic flow at the intersection of this type. In present CA model, new rules are designed to avoid the conflicts among different directional vehicles and eliminate the gridlock. Two kinds of performance measures (i.e., flux and average control delay) for intersection are compared. The impacts of U-turn movements are analyzed under different initial conditions. Simulation results demonstrate that (i) the average control delay is more practical than flux in measuring the performance of intersection, (ii) U-turn movements increase the range and degree of high congestion, and (iii) U-turn movements on the different direction of main road have asymmetrical influences on the traffic conditions of intersection

Current Situation and Developing Countermeasures of Postgraduate Innovation Center in China

Innovation is the driving force to promote the development of our nation. Postgraduate education, as an important approach to cultivate high-level talents, is a major part of the national innovation system. The establishment of the Postgraduate Innovation Center has an important significance for the cultivation of innovative talents in colleges and universities. This paper expounds the connotation and characteristics of Postgraduate Innovation Center and analyzes its current situation, operation mode, function orientation, institution settings and the innovative products. The paper also points out the problems in the current situation of the Postgraduate Innovation Center and finds the factors which restrict the development of the center. Finally, the paper puts forward some corresponding countermeasures

Optimizing selection of competing services with probabilistic hierarchical refinement

Recently, many large enterprises (e.g., Netflix, Amazon) have decomposed their monolithic application into services, and composed them to fulfill their business functionalities. Many hosting services on the cloud, with different Quality of Service (QoS) (e.g., availability, cost), can be used to host the services. This is an example of competing services. QoS is crucial for the satisfaction of users. It is important to choose a set of services that maximize the overall QoS, and satisfy all QoS requirements for the service composition. This problem, known as optimal service selection, is NP-hard. Therefore, an effective method for reducing the search space and guiding the search process is highly desirable. To this end, we introduce a novel technique, called Probabilistic Hierarchical Refinement (ProHR). ProHR effectively reduces the search space by removing competing services that cannot be part of the selection. ProHR provides two methods, probabilistic ranking and hierarchical refinement, that enable smart exploration of the reduced search space. Unlike existing approaches that perform poorly when QoS requirements become stricter, ProHR maintains high performance and accuracy, independent of the strictness of the QoS requirements. ProHR has been evaluated on a publicly available dataset, and has shown significant improvement over existing approaches.No Full Tex

2,2′-[1,1′-(Propane-1,3-diyldioxy­dinitrilo)diethyl­idyne]diphenol

The title compound, C19H22N2O4, was synthesized by the reaction of 2′-hydroxy­acetophenone with 1,3-bis­(amino­oxy)propane in ethanol. Intra­molecular O—H⋯N and weak C—H⋯O hydrogen bonds stabilize the three-dimensional structure. A twofold rotation axis passes through the molecule