269 research outputs found

    Impact of irreversibility and uncertainty on the timing of infrastructure projects

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    This paper argues that because of the irreversibility and uncertainty associated with Build - Operate - Transfer (BOT) infrastructure projects, their financial evaluation should also routinely include the determination of the value of the option to defer the construction start-up. This ensures that project viability is comprehensively assessed before any revenue or loan guarantees are considered by project sponsors to support the project. This paper shows that the framework can be used even in the context of the intuitive binomial lattice model. This requires estimating volatility directly from the evolution of the net operating income while accounting for the correlation between the revenue and costs functions. This approach ensures that the uncertainties usually associated with toll revenues, in particular, are thoroughly investigated and their impact on project viability is thoroughly assessed. This paper illustrates the usefulness of the framework with data from an actual (BOT) toll road project. The results show that by postponing the project for a couple of years the project turns out to be viable, whereas it was not without the deferral. The evaluation approach proposed therefore provides a better framework for determining when and the extent of government financial support, if any, that may be needed to support a BOT project on the basis of project economics. The analysis may also be applicable to private sector investment projects, which are characterized by irreversibility and a high rate of uncertainty

    A real time demonstrative analysis of lightweight payload encryption in resource constrained devices based on mqtt

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    06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Kısıtlı cihazların kaynakları, yani bellek (ROM ve RAM), CPU ve pil ömrü (varsa) sınırlıdır. Genellikle, veri toplayan sensörler, makinadan makineye (M2M) veya servisleri ve elektrikli ev aletlerini kontrol eden akıllı cihazlar için puanlar. Bu tür aygıtlar bir ağa bağlandığında "nesnelerin Internet'i" nin (IoT) bir parçasını oluştururlar. Message Queue Telemetry Transport (yani MQTT), hafif, açık, basit, istemci-sunucu yayın/abone mesajlaşma taşıma protokolüdür. Güvenilir iletişim için üç Hizmet Kalitesi (QoS) seviyesini destekleyen çoğu kaynak kısıtlamalı IoT cihazı için kullanışlıdır ve verimlidir. Cihazdan Cihaza (D2D) ve nesnelerin Internet'i (IoT) bağlamları gibi kısıtlı ortamlarda iletişim için gerekli olan bir protokoldür. MQTT protokolü, güvenli soket katmanı (SSL) sertifikalarına dayalı taşıma katmanı güvenliği (TLS) dışında somut güvenlik mekanizmalarından yoksundur. Bununla birlikte, bu güvenlik protokollerinin en hafif değildir ve özellikle kısıtlı cihazlar için ağ yüklerini artırır. IoT cihazlarının yaklaşık %70'inde özellikle de istemci tarafında veri şifrelemesi yoktur ve TLS için mükemmel bir alternatif olabilir. Bu tezde, farklı Hizmet Kalitesi (QoS) ve veri yüklerin değişken boyutu için kısıtlı bir cihaz üzerinde MQTT protokolünün ağ performansı üzerindeki etkisini göstermek için bir deney düzeneği tasarlanmıştır. Bu çalışmanın yeni kısmı, yüklerin istemci tarafında şifrelenmesini ve ağ performansı üzerindeki etkisini kapsıyor. Denemelerde, verilere 128-bits ileileri şifreleme standardı (AES) hafif bir şifreleme uygulanmıştır. Mesajlar, farklı yük boyutlarına dayanan bir komisyoncu sunucusu aracılığıyla gerçek kablolu alt uçtakı yayıncılık istemcisi ve düşük uçtakı abone istemcisi üzerinden MQTT'deki üç farklı QoS seviyesini kullanarak aktarılır. Paketler, şifreleme ve şifre çözme işlem süresinin ölçülmesiyle birlikte uçtan uca gecikme, verimlilik ve mesaj kaybı analiz etmek için yakalanır. Deney sonuçlarına göre, şifrelenmemiş (şifresiz metin) yükün daha düşük bir ağ yük etkisine sahip olduğu ve bu nedenle, yüzde kaybı ve mesaj tesliminde, şifreli yüke göre MQTT'yi kullanarak nispeten daha iyi bir ağ performansı ürettiği sonucuna varılmıştır.Constrained devices are limited in resources namely, memory (ROM and RAM), CPU and battery life (if available). They are often used as sensors that collects data, machine to machine (M2M) or smart devices that control services and electrical appliances. When such devices are connected to a network they form what is called "things" and in a whole, they form part of the "Internet of Things" (IoT). Message Queue Telemetry Transport (MQTT) is a common light weight, open, simple, client-server publish/subscribe messaging transport protocol useful and efficient for most resource constrained IoT devices that supports three Quality of Service (QoS) levels for reliable communication. It is an essential protocol for communication in constrained environments such as Device to Device (D2D) and Internet of Things (IoT) contexts. MQTT protocol is devoid of concrete security mechanisms apart from Transport Layer Security (TLS) based on Secure Socket Layer (SSL) certificates. However, this is not the lightest of security protocols and increases network overheads especially for constrained devices. About 70 % of most ordinary IoT devices also lack data encryption especially at the client-end which could have been a perfect alternative for TLS. In this thesis, an experimental setup is designed to demonstrate the effect on network performance of MQTT protocol on a constrained device for different Quality of Service (QoS) and variable size of payloads. The novel part of this study covers client-side encryption of payloads and its effect over network performance. In the experiments, a lightweight encryption of 128-bits Advanced Encryption Standard (AES) is applied on the data. The messages are transferred using the three different QoS levels in MQTT over real wired low-end publish client and low-end subscriber client via a broker server based on different payload sizes. The packets are captured to analyze end-to-end latency, throughput and message loss along with the measurement of encryption and decryption processing time. According to the results of the experiment, it was concluded that, non-encrypted (plaintext) payload have a lower network load effect and hence produces a relatively better network performance using MQTT in terms of percentage loss and message delivery than the encrypted payload

    The Impacts of Banking System Stability on Sustainable Development: Conditional Mean-Based and Parameter Heterogeneity Approaches

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    We explored the impacts of banking system stability on sustainable development for the period 2000-2016 as well pre and post-global financial crisis periods. We employed econometric frameworks of dynamic fixed effects, system GMM and most recent estimator - panel quantile regression with fixed effects to provide robust results from the conditional mean-based and parameter heterogeneity approaches. Our results revealed that, conditioning on other sustainable development determinants, banking system stability have significant impacts on sustainable development as well as empirical evidence of parameter heterogeneity response of sustainable development for countries conditionally distributed on low and high sustainable development path for both short-run and long-run. In addition, we established that, countries distributed on low sustainable development paths gain more from bank stabilization policies compared to countries on middle and higher sustainable development paths. Finally, we established vanishing adverse effects of banking system stability on sustainable development in the post-global financial crisis period

    Methodology and applications of city level CO2 emission accounts in China

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    China is the world's largest energy consumer and CO2 emitter. Cities contribute 85% of the total CO2 emissions in China and thus are considered as the key areas for implementing policies designed for climate change adaption and CO2 emission mitigation. However, the emission inventory construction of Chinese cities has not been well researched, mainly owing to the lack of systematic statistics and poor data quality. Focusing on this research gap, we developed a set of methods for constructing CO2 emissions inventories for Chinese cities based on energy balance table. The newly constructed emission inventory is compiled in terms of the definition provided by the IPCC territorial emission accounting approach and covers 47 socioeconomic sectors, 17 fossil fuels and 9 primary industry products, which is corresponding with the national and provincial inventory. In the study, we applied the methods to compile CO2 emissions inventories for 24 common Chinese cities and examined uncertainties of the inventories. Understanding the emissions sources in Chinese cities is the basis for many climate policy and goal research in the future

    The effects of FDI, economic growth and energy consumption on carbon emissions in ASEAN-5: Evidence from panel quantile regression

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    This study investigates the impact of foreign direct investment (FDI), economic growth and energy consumption on carbon emissions in five selected member countries in the Association of South East Asian Nations (ASEAN-5), including Indonesia, Malaysia, the Philippines, Singapore and Thailand. This paper employs a panel quantile regression model that takes unobserved individual heterogeneity and distributional heterogeneity into consideration. Moreover, to avoid an omitted variable bias, certain related control variables are included in our model. Our empirical results show that the effect of the independent variables on carbon emissions is heterogeneous across quantiles. Specifically, the effect of FDI on carbon emissions is negative, except at the 5th quantile, and becomes significant at higher quantiles. Energy consumption increases carbon emissions, with the strongest effects occurring at higher quantiles. Among the high-emissions countries, greater economic growth and population size appear to reduce emissions. The results of the study also support the validity of the halo effect hypothesis in higher-emissions countries. However, we find little evidence in support of an inverted U-shaped curve in the ASEAN-5 countries. In addition, a higher level of trade openness can mitigate the increase in carbon emissions, especially in low- and high-emissions nations. Finally, the results of the study also provide policymakers with important policy recommendations

    Comparative study on finance‐growth nexus in Malaysia and Indonesia: Role of institutional quality

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    The impact of financial development (FD) on economic growth in the context of Malaysia and Indonesia has been examined in this study regarding the role of the financial crisis and strategic changes in the institutional setup. Autoregressive distributed lags and threshold regression were applied, and time series data were analyzed for the period between 1984 and 2017 revealing that FD promoted the economic growth in both economies during this period. A nonlinear analysis also revealed that FD and economic growth follow an inverted U‐shape relation in the case of Malaysia whereas, in Indonesia, it followed a U‐shape relation. It was discovered that not all measures of FD promote economic growth. For instance, market capitalization was profound in the Malaysian economy while credit to the private sector and money supply was conducive for the Indonesian economy. The analysis demonstrated that the Asian and global financial crisis adversely affected economic growth in the case of Indonesia due to poor institutional quality (IQ), whereas in Malaysia it was relatively safe from the adversity brought about by the financial crisis due to the presence of IQ and good corporate governance. However, a positive change in IQ was found to have a much greater impact on augmenting economic growth rather than playing a mediating role in connection with FD and economic growth in Malaysia. In the context of Indonesia however, IQ was found to impede economic growth but played a positive and significant mediating role in the nexus of FD and economic growth. The spill‐over analysis revealed that Malaysian FD is positively associated with Indonesian economic growth while Indonesian FD is negatively associated with the Malaysian economy. This study provided all economic and anecdotal explanations in supporting the results of this study

    Environmental implications of increased US oil production and liberal growth agenda in post-Paris Agreement era

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    Contextualising on the internationally low oil prices era and historically high oil production in USA and refusal to honour the commitments under Paris Agreement (COP: 21), this study investigates the role of education, oil prices and natural resources on energy demand and CO2 emissions in the USA for the period of 1976–2016. In so doing, we employed a bounds testing approach to cointegration accounting for structural breaks in the series. Key findings suggest the presence of a long-run association between underlying variables. The abundance of natural resources and economic growth of the US economy seem to weigh on environmental quality by increasing energy consumption and carbon emissions. Oil prices show a negative association with energy consumption as well as carbon emissions suggesting that a low oil prices regime can lead to an increase in carbon emissions and energy consumption. Interestingly, education seems to play an important role by reducing energy consumption and carbon emissions, resultantly improving the US environmental quality. Our findings have profound environmental implications in terms of efforts to tackle climate change and meeting the Paris agreement (COP: 21) ambitions with reality and USA policy stance

    Money: A Market Microstructure Approach

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    The current discussion about the future of the financial system draws heavily on a set of theories known as the ‘New Monetary Economics’. The New Monetary Economics predicts that deregulation and financial innovation will lead to a moneyless world. This paper uses a market microstructure approach to show that a common medium of exchange that serves as unit of account will remain a necessary instrument to reduce transaction costs. This finding is supported by empirical evidence from foreign exchange markets
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