38 research outputs found
Trace formulas for Schrödinger operators on star graphs
We derive trace formulas of the Buslaev–Faddeev type for quantum star graphs. One of the new ingredients is high energy asymptotics of the perturbation determinant
Application of Activity Based Costing in Reverse Logistics Environment: A Case of End-of-life Vehicle Recovery in Turkey
Nowadays, there has been a growing interest in reverse logistics in both theory
and practice due to legislations, economic and ecological benefits, and social
responsibilities. If enterprises incorporating reverse logistics activities to its structure
want to realize the required level of customer service and comply with related
obligations at the lowest total cost, analyzing the actualized reverse logistics activities
and correct determination and reduction of costs of these activities are essential for
them. Traditional accounting methods are inadequate for accurate assignment of
overhead costs. In this paper, an actual application of Activity Based Costing (ABC) to
reverse logistics activities is presented in order to help managers to improve their
understanding of costs that arises from reverse logistics activities. An illustrative case
study in the end-of-life vehicle (ELV) recovery industry in Turkey is presented to
demonstrate the steps of how ABC is applied to reverse logistics systems. The results
enable to efficient management of reverse logistics activities and their costs in an ELV
recovery chain and exhibit which reverse logistics activities performed by a dismantler
cause the highest cost and can be improved. In the case study, products (ELVs) are
evaluated as inputs and the obtained materials from reverse logistics activities are
evaluated as outputs of the system by force of the nature of reverse logistics. Results
show that while most cost of the company (52.7%) was related with the output of B
Group of components/parts (sent to shredders); the minimum cost (12.3%) was realized
for the output of A Group components/parts (sent to recyclers). The remaining 35% of
the costs belong to the C Group of outputs (sent to secondary markets)
The spectral shift function and Levinson's theorem for quantum star graphs
We consider the Schr\"odinger operator on a star shaped graph with edges
joined at a single vertex. We derive an expression for the trace of the
difference of the perturbed and unperturbed resolvent in terms of a Wronskian.
This leads to representations for the perturbation determinant and the spectral
shift function, and to an analog of Levinson's formula
Spectral Inequalities for Quantum Graphs
We review our joint work with Evans Harrell on semiclassical and universal inequalities for quantum graphs. The proofs of these inequalities are based on an abstract trace inequality for commutators of operators. In this article we give a new proof of this abstract trace inequality. Another ingredient in proving semiclassical and universal inequalities is an appropriate choice of operators in this trace inequality. We provide a new approximation method for such a choice
ADAPTATION OF THE ATTITUDE TOWARD SUSTAINABLE DEVELOPMENT SCALE TO TURKISH
This study aimed to adapt the Attitudes toward Sustainable Development Scale (ASDS) to Turkish. To this end,
the ASDS, which has 20 items in the dimensions of environment, economy, society, and education, was translated
into Turkish and piloted in a group of 205 pre-service science teachers. Two items were revised based on the
preliminary findings of the pilot study. Then, the revised instrument was administered to 281 pre-service science
teachers. Confirmatory factor analysis results supported the 4-factor structure. Convergent and discriminant
validity evidence was also obtained for the Turkish version of the ASDS. Additionally, reliability analyses
suggested high internal consistency. The results related to the measurement invariance across gender showed
that the data from both male and female pre-service science teachers lead to equally valid conclusions concerning
attitude toward sustainable development. Overall, the findings suggested that Turkish version of the Attitudes
toward Sustainable Development Scale can be utilized as a valid and reliable instrument to measure and
understand the pre-service science teachers’ attitudes toward sustainable development.</p