A systematic method of project selection based on risk and return criteria and according to the mean-semi-deviation behavioral hypothesis

The uncertain problem of Industrial project selection is the topic of discussion in this article. As the unrealistic assumption of certainty is relaxed in this problem, the decision maker is faced with a two-criterion decision model in which justifying between Risk and Return are the main concerns. The concept of Risk has been revised and the “Semi-Deviation” measure has been proposed to represent the risk of a project. Based on the new Mean-Semi-deviation Behavior, and according to Utility and Modern Portfolio theories, a more efficient method of project evaluation will be presented

Empirical multi-wavelength prediction method for very high energy gamma-ray emitting BL Lacs

Aim: We have collected the most complete multi-wavelength ($6.0 - 6.0 \times 10^{-18} cm$) dataset of very high energy (VHE) $\gamma$-ray emitting (TeV) BL Lacs, which are the most numerous extragalactic VHE sources. Using significant correlations between different bands, we aim to identify the best TeV BL Lac candidates that can be discovered by the current and next generation of imaging air Cherenkov telescopes. Methods: We formed five datasets from lower energy data, i.e. radio, mid-infrared, optical, X-rays, and GeV $\gamma$-ray, and five VHE $\gamma$-ray datasets to perform a correlation study between different bands and to construct the prediction method. The low energy datasets were averaged for individual sources, while the VHE $\gamma$-ray data were divided into subsets according to the flux state of the source. We then looked for significant correlations and determined their best-fit parameters. Using the best-fit parameters we predicted the level of VHE $\gamma$-ray flux for a sample of 182 BL Lacs, which have not been detected at TeV energies. We identified the most promising TeV BL Lac candidates based on the predicted VHE $\gamma$-ray flux for each source. Results: We found 14 significant correlations between radio, mid-infrared, optical, $\gamma$-ray, and VHE $\gamma$-ray bands. The correlation between optical and VHE $\gamma$-ray luminosity is established for the first time. We attribute this to the more complete sample and more accurate handling of host galaxy flux in our work. We found nine BL Lac candidates whose predicted VHE $\gamma$-ray flux is high enough for detection in less than 25 hours with current imaging air Cherenkov telescopes.Comment: 10 pages, 2 figures, 4 Table

Applying Metacognitive Strategies in Comprehending English Reading Texts

Comprehending English text is still regarded as hard for students. Metacognitive strategies have been considered effective in overcoming reading difficulties by many researchers. The objective of this study is to describe the application of three types of metacognitive reading strategies (global strategies, problem solving strategies, and support strategies) used by the students of Senior High School (SMAN) 1 Ingin Jaya, Aceh Besar. It is a descriptive qualitative study. Metacognitive Awareness of Reading Strategies Inventory (MARSI) questionnaire suggested by Mokhtari and Reichard (2002) was used to collect the data. The result of the study revealed that the students generally showed moderate awareness of all strategies and held a preference of using Problem Solving Strategies, followed by Support Strategies and Global Strategies respectively. The study also showed that high performance students used the strategies more frequently than low performance students. It can be concluded that the more students aware of using metacognitive reading strategies, the better their performance is in reading skill. Therefore, teaching the students to use metacognitive strategies can be a solution in enhancing students’ reading ability

Unmanned vehicles formation control in 3D space and cooperative search

The first problem considered in this dissertation is the decentralized non-planar formation control of multiple unmanned vehicles using graph rigidity. The three-dimensional formation control problem consists of n vehicles operating in a plane Q and r vehicles that operate in an upper layer outside of the plane Q. This can be referred to as a layered formation control where the objective is for all vehicles to cooperatively acquire a predefined formation shape using a decentralized control law. The proposed control strategy is based on regulating the inter-vehicle distances and uses backstepping and Lyapunov approaches. Three different models, with increasing level of complexity are considered for the multi-vehicle system: the single integrator vehicle model, the double integrator vehicle model, and a model that represents the dynamics of a class of robotics vehicles including wheeled mobile robots, underwater vehicles with constant depth, aircraft with constant altitude, and marine vessels. A rigorous stability analysis is presented that guarantees convergence of the inter-vehicle distances to desired values. Additionally, a new Neural Network (NN)-based control algorithm that uses graph rigidity and relative positions of the vehicles is proposed to solve the formation control problem of unmanned vehicles in 3D space. The control law for each vehicle consists of a nonlinear component that is dependent on the closed-loop error dynamics plus a NN component that is linear in the output weights (a one-tunable layer NN is used). A Lyapunov analysis shows that the proposed distance-based control strategy achieves the uniformly ultimately bounded stability of the desired infinitesimally and minimally rigid formation and that NN weights remain bounded. Simulation results are included to demonstrate the performance of the proposed method. The second problem addressed in this dissertation is the cooperative unmanned vehicles search. In search and surveillance operations, deploying a team of unmanned vehicles provides a robust solution that has multiple advantages over using a single vehicle in efficiency and minimizing exploration time. The cooperative search problem addresses the challenge of identifying target(s) in a given environment when using a team of unmarried vehicles by proposing a novel method of mapping and movement of vehicle teams in a cooperative manner. The approach consists of two parts. First, the region is partitioned into a hexagonal beehive structure in order to provide equidistant movements in every direction and to allow for more natural and flexible environment mapping. Additionally, in search environments that are partitioned into hexagons, the vehicles have an efficient travel path while performing searches due to this partitioning approach. Second, a team of unmanned vehicles that move in a cooperative manner and utilize the Tabu Random algorithm is used to search for target(s). Due to the ever-increasing use of robotics and unmanned systems, the field of cooperative multi-vehicle search has developed many applications recently that would benefit from the use of the approach presented in this dissertation, including: search and rescue operations, surveillance, data collection, and border patrol. Simulation results are presented that show the performance of the Tabu Random search algorithm method in combination with hexagonal partitioning

Bl lac objects - view from the highest energies

Relativistic jets launched by a super-massive black holes are among the most extreme particle accelerators in the Universe. BL Lac objects host a relativistic jet that points very close to our line of sight. They are the most numerous sources in the extragalactic very-high-energy (VHE > 100 GeV) gamma-ray sky and have been suggested to be possible sources of astrophysical neutrinos. Additionally, due to their high brightness, they can be used to study many fundamental problems like the properties of the Universe between us and them. However, in order to do so, we need to know the intrinsic spectrum of many BL Lac objects and the emission mechanisms that cause their variability. In this thesis, some of the long-standing questions about BL Lac objects are addressed using multi-wavelength data. With the aim of increasing the number of the BL Lac objects in the VHE gamma-ray sky, a prediction method needs to be developed. As an outcome, a candidate list of VHE gamma-ray emitting (TeV) BL Lac objects is provided for further observations. Three of these candidates (S2 0109+22, TXS 0210+515, and 1ES 2037+521) were followed by VHE gamma-ray observations. I performed a detailed study of these three sources. In archival data, they had di_erent classi_cations. S2 0109+22 was classi_ed as an intermediate synchrotron peaked source, while the other two were identi_ed as extreme high synchrotron peaked source (EHBL) candidates. Only a handful of both have been detected at VHE gamma rays. S2 0109+22 was detected in a aring state, and during this period the peaks of its spectral energy distribution (SED) moved to higher energies. The two other sources showed no variability and our study con_rmed them as EHBLs. I have also studied the emission models of TeV BL Lac objects. I performed a detailed study of _ve TeV blazars by applying a two-component model which takes into account the observational constraints in the radio and optical bands. I found that such a model can reproduce the observed SEDs. Unlike one-zone models, the model does not require very low magnetic _eld strengths and it does not ignore the radio part of the SED