Kadir Has Universitesi
http://academicrepository.khas.edu.tr:80
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sat, 08 May 2021 04:30:35 GMT2021-05-08T04:30:35ZEnergy and Sustainable Development from Perspective of Energy Poverty
https://hdl.handle.net/20.500.12469/4012
Energy and Sustainable Development from Perspective of Energy Poverty
Ucal, Meltem Şengün
End of poverty, the number one Sustainable Development Goal, focuses on ending all kinds of poverty all over the world. The elimination of all forms of poverty continues to be the biggest problem facing humanity today. The most important problems that have been encountered since the beginning of the energy use are the increasing risk of deterioration of energy supply, energy production and energy poverty. The problem of energy poverty among them is widely mentioned in the literature. In general, the studies on the subject focus on how the problem is defined worldwide, its size, its consequences, the obstacles to the elimination of the problem and some solution opportunities. The term “energy poverty” can refer to two different socio-economic issues, depending on the geographical scope of its application: energy affordability in higher income and developed states; inadequate access to “modern” energy services in most low income or developing countries”. Poor people pay a high price for the energy they use, either in cash or by labor. In addition, poor households spend more on energy than wealthy people, not only because their income is much smaller, but also because the fuels and equipment they use are much less efficient than modern fuels and equipment. No country has been able to diminish energy poverty to a great extent without increasing energy use. Decreasing the global inequality in energy is key to reducing income, gender and an inequality in other dimensions such as rural/urban income gaps. From this perspective, the importance of the relationship between energy poverty and sustainable development will be discussed by making comparisons by taking the country cases into consideration in the context of energy efficiency and renewable energy. The regional understanding of these concepts will also be discussed in this context.
Fri, 01 Jan 2021 00:00:00 GMThttps://hdl.handle.net/20.500.12469/40122021-01-01T00:00:00ZPhase Shifting Properties of High-Pass and Low-Pass Mixed-Element Two-Ports
https://hdl.handle.net/20.500.12469/4011
Phase Shifting Properties of High-Pass and Low-Pass Mixed-Element Two-Ports
Şengül, Metin Y.; Çakmak, Gökhan; Özdemir, Rabia
n many applications, circuits containing lumped-elements are preferred because of their small sizes. But it is not possible to avoid losses caused by the connections between lumped-elements at high frequencies. However, the use of these connections as circuit elements will improve the performance of the circuit. Therefore, it becomes inevitable to use circuits with mixed (lumped and distributed) elements at high frequencies. In this brief, phase shifting properties of high-pass and low-pass mixed-element two-ports is explained. Then these two-ports are used to form the initial design of high-pass and low-pass sections of a phase shifter. Finally, the initial design performance can be improved by means of commercially available computer-aided design (CAD) tools.
Thu, 01 Apr 2021 00:00:00 GMThttps://hdl.handle.net/20.500.12469/40112021-04-01T00:00:00ZGromov product structures, quadrangle structures and split metric spaces
https://hdl.handle.net/20.500.12469/4010
Gromov product structures, quadrangle structures and split metric spaces
Bilge, Ayşe Hümeyra; Çelik, Derya; Koçak, Şahin; Rezaeinazhad, Arash Mohammadian
Let (X,d) be a finite metric space with elements Pi, i=1,…,n and with distances dij≔d(Pi,Pj) for i,j=1,…,n. The “Gromov product” Δijk, is defined as [Formula presented]. (X,d) is called Δ-generic, if, for each fixed i, the set of Gromov products Δijk has a unique smallest element, Δijiki. The Gromov product structure on a Δ-generic finite metric space (X,d) is the map that assigns the edge Ejiki to Pi. A finite metric space is called “quadrangle generic”, if for all 4-point subsets {Pi,Pj,Pk,Pl}, the set {dij+dkl,dik+djl,dil+djk} has a unique maximal element. The “quadrangle structure” on a quadrangle generic finite metric space (X,d) is defined as a map that assigns to each 4-point subset of X the pair of edges corresponding to the maximal element of the sums of distances. Two metric spaces (X,d) and (X,d′) are said to be Δ-equivalent (Q-equivalent), if the corresponding Gromov product (quadrangle) structures are the same up to a permutation of X. We show that Gromov product classification is coarser than the metric fan classification. Furthermore it is proved that: (i) The isolation index of the 1-split metric δi is equal to the minimal Gromov product at the vertex Pi. (ii) For a quadrangle generic (X,d), the isolation index of the 2-split metric δij is nonzero if and only if the edge Eij is a side in every quadrangle whose set of vertices includes Pi and Pj. (iii) For a quadrangle generic (X,d), the isolation index of an m-split metric δi1…im is nonzero if and only if any edge Eikil is a side in every quadrangle whose vertex set contains Pik and Pil. These results are applied to construct a totally split decomposable metric for n=6.
Tue, 01 Jun 2021 00:00:00 GMThttps://hdl.handle.net/20.500.12469/40102021-06-01T00:00:00ZForecasting time-varying arrivals: Impact of direct response advertising on call center performance
https://hdl.handle.net/20.500.12469/4009
Forecasting time-varying arrivals: Impact of direct response advertising on call center performance
Kıygı-Çallı, Meltem; Weverbergh, Marcel; Franses, Philip Hans
This study investigates manpower planning and the performance of a national call center for scheduling car repairs and responding to road interventions. We model the impact of advertising on the required capacity and develop a forecasting model for incoming calls, where the impact of direct-response advertising is considered. With the estimation results, we forecast the number of incoming calls to the call center. Next, the forecasts are input into the capacity planning simulation module to directly simulate a service process at the highly disaggregated level. This simulation mimics the service level requirements and queue behavior and shows that the call center is operating at a high level of efficiency and performance. We illustrate that advertising may cause a temporary overload of the system and increase the number of abandoned calls, which is suboptimal for call center performance.
Thu, 01 Jul 2021 00:00:00 GMThttps://hdl.handle.net/20.500.12469/40092021-07-01T00:00:00Z