The effects of qos level degradation cost on provider selection and task allocation model in telecommunication networks

Firms acquire network capacity from multiple suppliers which offer different Quality of Service (QoS) levels. After acquisition, day-to-day operations such as video conferencing, voice over IP and data applications are allocated between these acquired capacities by considering QoS requirement of each operation. In optimal allocation scheme, it is generally assumed each operation has to be placed into resource that provides equal or higher QoS Level. Conversely, in this study it is showed that former allocation strategy may lead to suboptimal solutions depending upon penalty cost policy to charge degradation in QoS requirements. We model a cost minimization problem which includes three cost components namely capacity acquisition, opportunity and penalty due to loss in QoS

A bi-objective genetic algorithm approach to risk mitigation in project scheduling

A problem of risk mitigation in project scheduling is formulated as a bi-objective optimization problem, where the expected makespan and the expected total cost are both to be minimized. The expected total cost is the sum of four cost components: overhead cost, activity execution cost, cost of reducing risks and penalty cost for tardiness. Risks for activities are predefined. For each risk at an activity, various levels are defined, which correspond to the results of different preventive measures. Only those risks with a probable impact on the duration of the related activity are considered here. Impacts of risks are not only accounted for through the expected makespan but are also translated into cost and thus have an impact on the expected total cost. An MIP model and a heuristic solution approach based on genetic algorithms (GAs) is proposed. The experiments conducted indicate that GAs provide a fast and effective solution approach to the problem. For smaller problems, the results obtained by the GA are very good. For larger problems, there is room for improvement

A biobjective genetic algorithm approach to project scheduling under risk

A problem of risk mitigation in project scheduling is formulated as a bi-objective optimization problem, where the expected makespan and the expected total cost are both to be minimized. The expected total cost is the sum of four cost components: overhead cost, activity execution cost, cost of reducing risks and penalty cost for tardiness. Risks for activities are predefined. For each risk at an activity, various levels are defined, which correspond to the results of different preventive measures. Only those risks with a probable impact on the duration of the related activity are considered here. Impacts of risks are not only accounted for through the expected makespan but are also translated into cost and thus have an impact on the expected total cost. An MIP model and a heuristic solution approach based on genetic algorithms (GAs) is proposed and tested. The experiments conducted indicate that GAs provide a fast and effective solution approach to the proble m. For smaller problems, the results obtained by the GA are very good. For larger problems, there is room for improvement

Four payment models for the multi-mode resource constrained project scheduling problem with discounted cash flows

In this paper, the multi-mode resource constrained project scheduling problem with discounted cash flows is considered. The objective is the maximization of the net present value of all cash flows. Time value of money is taken into consideration, and cash in- and outflows are associated with activities and/or events. The resources can be of renewable, nonrenewable, and doubly constrained resource types. Four payment models are considered: Lump sum payment at the terminal event, payments at prespecified event nodes, payments at prespecified time points and progress payments. For finding solutions to problems proposed, a genetic algorithm (GA) approach is employed, which uses a special crossover operator that can exploit the multi-component nature of the problem. The models are investigated at the hand of an example problem. Sensitivity analyses are performed over the mark up and the discount rate. A set of 93 problems from literature are solved under the four different payment models and resource type combinations with the GA approach employed resulting in satisfactory computation times. The GA approach is compared with a domain specific heuristic for the lump sum payment case with renewable resources and is shown to outperform it

The Effects of Recreative Activities on Adjustment Levels of Young People

This study was planned to determine the effect of a series of 8-week recreational activities on the personal, social and general adjustment levels and academic success of high school students (between 14-16 years). The data was collected from a total of 36 students, made up two groups each containing 18 members. They were all recruited voluntarily from students in the first year class of the Mugla Mimar Sinan High School. The data collected were analyzed using the SPSS 21 software and complemented by the Mann Whitney U and Kruskal-Wallis variance analysis techniques. Significant differences (0.01) were found between the pre-test and post-test scores for anti-social inclinations in the experimental group. Significant differences (0.01) also were found between the post-test scores for anti-social inclinations in the experimental and the control groups. Significant differences (0.05) were found between the pre-test and post-test scores for emotional determinants in the experimental group and the pre-test and post-test scores for social adjustment in the experimental group. No significant difference was found between other parameters among the groups. It was concluded at the end of the study that recreation was effective on the adjustment level of the adolescents and that this effect was also noted to positively affect the academic success of the subjects

INVESTIGATION OF THREE DIMENSIONAL SPATIAL ABILITY LEVELS

Spatial ability is an important factor affecting student achievement in science and mathematics education. In this study, it is aimed to investigate the spatial ability levels of students studying in chemistry department. Molecular model spatial ability test prepared for chemistry education was used in the study. The test measures spatial ability in two dimensions: rotation in space and visualization in the mind. In the research, t-test was used to determine whether there is a difference between the gender, class levels and the spatial ability and sub-dimensions of the molecular model. One-way analysis of variance was used to determine whether there was a difference between the achievement levels of the students and the spatial ability and sub-dimensions of the molecular model. No correlation was found between the gender and molecular model spatial ability and sub-dimensions of the students. There was a significant difference between students' class levels and spatial ability and sub-dimensions. As students' class levels increase, their ability to visualize increases. There was also a significant difference between the students' school achievements and the rotation of the molecular model in space with spatial ability and sub-dimensions and visualization in mind. The higher the grade point average, the more the ability to rotate and model the molecular model in space with its spatial ability and sub-dimensions.  Article visualizations

Context-aware LDA: Balancing Relevance and Diversity in TV Content Recommenders

In the vast and expanding ocean of digital content, users are hardly satisfied with recommended programs solely based on static user patterns and common statistics. Therefore, there is growing interest in recommendation approaches that aim to provide a certain level of diversity, besides precision and ranking. Context-awareness, which is an effective way to express dynamics and adaptivity, is widely used in recom-mender systems to set a proper balance between ranking and diversity. In light of these observations, we introduce a recommender with a context-aware probabilistic graphi-cal model and apply it to a campus-wide TV content de-livery system named “Vision”. Within this recommender, selection criteria of candidate fields and contextual factors are designed and users’ dependencies on their personal pref-erence or the aforementioned contextual influences can be distinguished. Most importantly, as to the role of balanc-ing relevance and diversity, final experiment results prove that context-aware LDA can evidently outperform other al-gorithms on both metrics. Thus this scalable model can be flexibly used for different recommendation purposes

CHEMISTRY WITH METAPHORS: CASE OF KOCAELI (TURKEY) VOCATIONAL SCHOOL

The aim of this study is to investigate the metaphors of chemistry students about chemistry science. For this purpose, a single question was asked to measure their perceptions about chemistry. Qualitative method was adopted in the research. Content analysis was applied to the data obtained. The sample of the study consists of students of Chemistry Program of Kocaeli Vocational School. Data were collected in the fall semester of 2018-2019. 68 students participated in the study. The reliability of the study was found to be 96% according to expert opinion. 32 metaphors were obtained. The metaphors obtained were collected in 7 themes: danger, comprehensive, cumulative, happiness, exploratory, innovative, magical. Only one of the metaphors has been negatively evaluated under the others positive theme. It was observed that “life” metaphor was used the most. Female students produced 25 metaphors and male students produced 11 metaphors. Metaphors for two themes were produced by female students. Female students differ from male students in terms of the metaphors they produce.  Article visualizations

CHEMISTRY STUDENTS' OPINIONS ABOUT TAKING CHEMISTRY EDUCATION AS DISTANCE EDUCATION

The aim of this study is to determine the opinions of the students studying in chemical and chemical processing technologies departments on take chemistry education in the form of distance education. The research sample consists of students studying in chemistry and petrochemical technology programs in Kocaeli Vocational School. It was applied to students studying in related departments in the fall semester of 2018-2019. The sample consists of 149 students. The mixed method has been adopted in the research. Scale and interview questions were prepared with the literature review. The reliability coefficient of the Chemistry Distance Education Scale was 0.945. There was a high correlation between the dimensions of the scale consisting of three dimensions. In quantitative research; a relationship was found between income and chemistry distance education. It was found that students with low income level were eligible for distance education in chemistry. Distance education diminish students' costs of housing and transportation. In addition, there is no relationship between the gender of the students, the type of education, the level of education of the parents, the department and the class. The qualitative research findings are: a large part of the students indicate that the distance education infrastructure is not sufficient. According to the students, chemistry education is considered to be sufficient for theoretical knowledge only as distance education. Students do not want to take laboratory applications as distance education. Distance education cannot eliminate the need to touch materials while adding visuality. It is determined that students are not ready to take chemistry education from distance education as cultural and cognitive.  Article visualizations