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- Yüksek Lisans TeziAçık Erişim2022OECD ülkelerinin COVID-19 pandemi yönetim etkinliklerinin değerlendirilmesi
Adem Yavuz Erdem
Performans analizi, sektörlerin, kaynaklarını belirledikleri hedefler doğrultusunda verimli ve etkin bir şekilde kullandıklarının göstergesi olan bir kavramdır. Sektör performanslarını karşılaştırmak için kullanılan yöntemlerden biride etkinlik analizidir. Etkinlik analizlerinde, parametrik olan ve parametrik olmayan gibi yöntemler uygulanmaktadır. Bu çalışmada sistemlerin etkinliklerinin ölçülmesinde kullanılan, birden çok ve birbirinden ayrık girdi ve çıktı değişkenlerini aynı potada değerlendirme kabiliyetine sahip olan ve parametrik olmayan, göreli etkinlik değerlendirme modeli veri zarflama analizi kullanılmıştır. Çalışmanın amacı; OECD ülkelerinin Covid-19 pandemi yönetim etkinliklerinin veri zarflama analizi (VZA) ile performans değerlendirmesini gerçekleştirmektir. Lindo paket programı kullanılarak etkinlik analizleri sonucunda karar verme birimlerine (KVB) ait göreli etkinlik değerleri tespit edilmiş, göreli etkin çıkmayan KVB' ler için referans kümeleri belirlenmiştir. Analizde girdi olarak; 1000 kişiye düşen doktor sayısı, hemşire sayısı, hasta yatağı sayısı ve sağlık harcamalarının GSYİH içindeki yüzdelik payı kullanılmıştır. Çıktı olarak ise; milyon kişi başına test sayısı, milyon kişi başına iyileşen vaka sayısı ve her 100 kişiye uygulanan Covid-19 aşı doz sayısı kullanılmıştır. Analizde çıktı yönelimli CCR ve BCC modelleri, bağlama bağlı VZA ile kullanılarak uygulanmış ve her seferinde etkin olmayan KVB' lere tekrar model çalıştırılmıştır. 1. seviye analiz sonucunda 37 KVB' nin 20' si etkin çıkmıştır. 2. seviyede etkin olmayan 17 KVB' nin 15' i etkin çıkmıştır. 3. ve son seviyede ise kalan 2 KVB' nin göreli en etkin olmayan KVB' ler olduğu görülmüştür. Her seviye sonunda etkin olmayan KVB' lere referans olan etkin KVB' lerin yoğunluk değerleri kullanılarak çıktı değişkenlerine hedef değerler belirlenmiş ve hesaplanan değişim yüzdeleri baz alınarak karar vericiler ve politika belirleyiciler için yol gösterici tavsiyelerde bulunulmuştur. Anahtar Kelimeler: Veri zarflama analizi, verimlilik, etkinlik, OECD, Covid-19.
- MakaleAçık Erişim2018Scopus SJRQ2The assessment of knowledge economy efficienccomparing Turkey with the European Union countries; [Procjena učinkovitosti ekonomije znanja: Usporedba turske s državama Europske Unije]
Ayan, Tuba Yakıcı; Pabuçcu, Hakan
Knowledge economy is an economy that produces, distributes and uses information. Nowadays, investment in quality information rather than capital inputs is becoming more and more important for countries to develop and to be able to compete with each other. The increasing speed in the creation and spreading of knowledge has made it a crucial component in economic development. It is a fact that the countries that make large investments in information factors experience a fast and sustainable growth and are the most dynamic and competitive countries in the world. In this paper, we use context dependent DEA to measure the relative efficiency of the European Union (EU) countries’, including Turkey, knowledge economy policy based on 2016 data. In addition, we implement factor-specific DEA in order to identify achievable targets in short term for each output of countries. Four outputs and three inputs were used in the analysis. The results showed that Germany is clearly ahead of other countries such as France, England, Malta and the Netherlands. Turkey, on the other hand, separates from other countries and is the least efficient one. The reason for this separation is that Turkey produces less output than expected relative to its facilities. Another conclusion of the paper is that the countries’ patent applications and high-tech exports are more inefficient than other knowledge economy outputs.
AtıfScopus2WoS2
İncele - MakaleYalnız künye2017Scopus SJRQ3EFFECTS OF AMBIENT CONDITIONS ON PERFORMANCE OF GAS TURBINE COGENERATION CYCLES
Karaali, Rabi; Öztürk, Ilhan Tekin
In this paper, effects of the ambient conditions on performance of cogeneration cycles are analyzed by Using exergy analysis method. These cogeneration cycles are the simple cycle, the air preheating cycle, the air-fuel preheating cycle and the inlet air cooling cycle. Also; these cycles are evaluated thermodynamically for different air and fuel mass ratio and the performance of these cycles are compared. The electrical power generation increases about 10-15 % by decreasing the inlet air temperature of the compressor from 25 degrees C to 0 degrees C. However, the thermal power decreases about 10 % with decreasing inlet air temperature. During the summer, the electric power can be easilyincreased 2-7 % by injecting water into the inlet air of the compressor. The exergetic efficiency of cycles is decreased 11-13 %; by decreasing the compressor inlet air pressure from 101.3 kPa to 70.18 kPa. But this change decreases the electric power generation about 25 %. The highest exergy efficiency is obtained for the air-fuel preheated cycle. The simple cycle is the best among the four cycles to obtain high heat rate and heat exergy. The effects of all ambient conditions on these cycles are considered simultaneously, analyzed and compared With each other in this study.
AtıfWoS3İncele - MakaleAçık Erişim2017Scopus SJRQ2Efficiency improvement of gas turbine cogeneration systems; [Poboljšanje učinkovitosti kogeneracijskih sustava plinske turbine]
Karaali, Rabi; Öztürk, İlhan Tekin
In this study eight methods are evaluated for a gas turbine cogeneration cycle to improve the efficiency. These methods are increasing gas turbine inlet air temperature, cooling the inlet air of the compressor, air preheating, fuel preheating, increasing compressor inlet air pressure, increasing air excess rates, steam injection, and humidification of the inlet air of the compressor. These methods are studied in order to compare their effects on the performance of the systems. The effects of these methods on the exergetic efficiency depend on the kind of the cogeneration cycle. By combining recuperation, preheating fuel and steam injection methods high efficiency can be achieved. The combined methods give the best results under variable heat demands of the market. An appropriate combination of the efficiency improvement methods may increase the exergetic efficiency about 20 %. The results show that efficiency improvement methods must be applied together whenever it is possible.
AtıfScopus8WoS6OpenAlex15İncele - MakaleAçık Erişim2016Scopus SJRQ1A novel roof type heat recovery panel for low-carbon buildings: An experimental investigation
Cuce, Pinar Mert; Cuce, Erdem; Riffat, Saffa
Energy saving and its efficient utilization is of prime interest in today's world due to the limited energy resources and growing significance of environmental issues. Despite the intensive efforts to narrow the gap between conventional energy sources (wood, coal, gas, oil, etc.) and renewables, renewable energy resources currently supply only about 14% of total world energy demand. In this regard, energy management and optimization are considered compulsory as much as the clean energy generation. Recent works indicate that the buildings play a significant role on global energy consumption. They are responsible for about 40% of global energy demand. Among the different building types, domestic buildings have the largest share with 63% and most of energy is utilized for heating, ventilation and air conditioning (HVAC) systems in those buildings. Energy consumption levels of buildings can be notably reduced through waste heat recovery in HVAC systems. There are several attempts in literature addressing the possibility of decreasing energy consumption of buildings via waste heat recovery technologies. The heat recovery technologies are cost effective and user friendly applications. The use of heat recovery systems aims at mitigating the energy consumption for HVAC applications as well as the greenhouse gas emissions, and hence decreasing the adverse effects of global warming on the Earth. It is well-documented in literature that the heat recovery systems are very promising for domestic applications. In this paper, experimental results of a novel heat recovery system developed for low-carbon buildings are presented. The proposed heat recovery system consists of a plate-type heat exchanger, blower fans and ducts. The parallel-flow arrangement is used to run the system. The system is designed as under roof application. The aim of the system is to recover waste heat and to preheat fresh air using stale air. The experiments of the system are carried out in winter season in Kent, UK. The study aims to investigate the coefficient of performance (COP) of the system as well as the heat recovery efficiency. The results show that the heat recovery efficiency of the proposed system is around 89% while the COP is 4.5. The proposed system can be used in both winter and summer conditions without requiring additional work. Its labor cost is extremely low, so it is cost-effective and user friendly.
AtıfScopus28WoS23OpenAlex31İncele