Scalable on-demand streaming of stored complex multimedia

Previous research has developed a number of efficient protocols for streaming popular multimedia files on-demand to potentially large numbers of concurrent clients. These protocols can achieve server bandwidth usage that grows much slower than linearly with the file request rate, and with the inverse of client start-up delay. This hesis makes the following three main contributions to the design and performance evaluation of such protocols. The first contribution is an investigation of the network bandwidth requirements for scalable on-demand streaming. The results suggest that the minimum required network bandwidth for scalable on-demand streaming typically scales as K/ln(K) as the number of client sites K increases for fixed request rate per client site, and as ln(N/(ND+1)) as the total file request rate N increases or client start-up delay D decreases, for a fixed number of sites. Multicast delivery trees configured to minimize network bandwidth usage rather than latency are found to only modestly reduce the minimum required network bandwidth. Furthermore, it is possible to achieve close to the minimum possible network and server bandwidth usage simultaneously with practical scalable delivery protocols. Second, the thesis addresses the problem of scalable on-demand streaming of a more complex type of media than is typically considered, namely variable bit rate (VBR) media. A lower bound on the minimum required server bandwidth for scalable on-demand streaming of VBR media is derived. The lower bound analysis motivates the design of a new immediate service protocol termed VBR bandwidth skimming (VBRBS) that uses constant bit rate streaming, when sufficient client storage space is available, yet fruitfully exploits the knowledge of a VBR profile. Finally, the thesis proposes non-linear media containing parallel sequences of data frames, among which clients can dynamically select at designated branch points, and investigates the design and performance issues in scalable on-demand streaming of such media. Lower bounds on the minimum required server bandwidth for various non-linear media scalable on-demand streaming approaches are derived, practical non-linear media scalable delivery protocols are developed, and, as a proof-of-concept, a simple scalable delivery protocol is implemented in a non-linear media streaming prototype system

Thermal storage/management system with phase change materials for building

Peer reviewe

Cold storage condensation heat recovery system with a novel composite phase change material

© 2016 Elsevier Ltd. Using condensation heat from cold storage refrigeration systems to provide heat for domestic hot water preparation and industrial hot water supply promotes energy conservation. However, few studies have investigated cold storage condensation heat recovery using phase change materials (PCMs). In this study, a cold storage condensation heat recovery system that uses PCMs has been designed and analysed. According to the principle of energy cascade recycling, different operation modes could be effectively switched to recycle condensation heat. Furthermore, a novel and suitable phase change composite material is developed for cold storage condensation heat recovery, which has a relatively large latent heat, high thermal conductivity, and an appropriate phase change temperature (i.e. 80 °C). With carnauba wax (CW) as the PCM and expanded graphite (EG) as the additive, a composite was developed with an optimal mass ratio of CW:EG = 10:1. The thermal and physical properties and the interior structure of the composite were then investigated using a scanning electron microscope (SEM), thermal constants analyser (Hot Disk), differential scanning calorimeter (DSC), and Fourier transform infrared spectrometer (FT-IR). Furthermore, experiments on the melting and solidification processes and accelerated thermal cycling were also conducted. It was found that at the optimal mass ratio of 10:1, the temperatures of the CW/EG composite in the melting and solidification processes were 81.98 °C and 80.43 °C, respectively, while the corresponding latent heats were 150.9 J/g and 142.6 J/g, respectively. During both processes, CW could retain its original worm-like structure after being completely adsorbed by EG. Compared to only CW, the melting and solidification time of the CW/EG composite were reduced by 81.7% and 55.3%, respectively, while its thermal conductivity was 16.4 times higher. After 1000 runs of accelerated thermal cycling, the endothermic/exothermic phase change temperatures of CW and the CW/EG composite increased by only 0.42%/0.42% and 0.23%/0.27%, respectively, while their endothermic/exothermic latent heats decreased by 4.96%/4.78% and 2.05%/3.44%, respectively. These results indicate that both CW and the CW/EG composite have excellent thermal reliability, while the CW/EG composite exhibits a slightly better performance. Finally, the experiments show that the CW/EG composite has desirable thermal and physical properties such as high thermal conductivity and reliability; Hence, it has good potenti al as a material for facilitating condensation heat recovery from cold storage refrigeration systems

Does central bank independence matter for the location choices of Chinese firms’ foreign investments?

Based on the eclectic paradigm and institutional theory, we hypothesize that Chinese firms prefer to invest in host countries having a central bank with a level of independence that is comparable to that of the Chinese central bank. Using data of Chinese listed firms from 1999 to 2013, our logit models suggests that all components of central bank independence, namely personnel, policy and financial independence, and priority for price stability, have a significant negative impact on the foreign investment location choices of Chinese firms. The impact of central bank independence on location choices is bigger for non-state-owned enterprises than for state-owned enterprises. The investment location choices of non-state-owned enterprises are negatively associated with the distance between central bank independence in China and that in host countries, while for state-owned enterprises this distance has no effect.</p

ANGIOTENSIN-(1-7)/MAS AXIS AND VASCULAR INFLAMMATION

Atherosclerosis, as a potentially serious condition, has become one of the most prevalent causes of mortality over the world. RAS (Reninangiotensin- system) is recognized to be a key role in the development of atherosclerosis, which considered as a chronic inflammatory disease. Ang II (angiotensin II) is proven to cause atherosclerosis, hypertension and aortic aneurysms. While activation of Mas receptors by Ang-(1-7) [angiotensin-(1- 7)] shows an important role in prevention of atherosclerosis. The activation of Ang-(1-7)/Mas receptor axis counteracts Ang II-induced hypertension, inflammation, fibrosis and apoptosis responses. We have concluded that, the relationship between Ang-(1-7)/Mas axis and vascular inflammation could be the paving-stone of the avoidance and novel treatment for atherosclerosis. The scope of this study is to review the relationship between Ang-(1-7)/Mas axis and vascular inflammation in the development of atherosclerosis

Localized Ridge Wrinkling of Stiff Films on Compliant Substrates

Wrinkling of thin stiff films on thick compliant elastomeric substrates subject to plane strain compression is considered for cases in which the substrate is pre-stretched prior to film attachment. Advanced wrinkling modes are investigated that evolve as the systems are compressed beyond the onset of the primary sinusoidal wrinkling mode. If the substrate pre-stretch is greater than about 40%, an advanced mode in the form of a series of well-spaced ridges separated by relatively flat film is observed in the simulations. Our experiments reveal a localization mode in the form of alternating packets of large and small amplitude wrinkles, but not ridges, while ridge formation has been observed in other recent experiments. Measurements of undulation amplitudes have been made for wrinkle fields of stiff films formed by oxidation of the surface of pre-stretched PDMS substrates. Simulations have been performed with a finite element model and an analytical film/substrate model. The formation of the ridge mode is a consequence of the altered nonlinearity of the substrate produced by the pre-stretch. The role of the tangential substrate stiffness in suppressing localization at the ridges is also highlighted. If there is no substrate pre-stretch, or if the substrate is pre-compressed, the primary sinusoidal mode gives way to an entirely different sequence of advanced modes usually entailing period doubling followed by folding. The nature of substrate nonlinearity that leads to ridges or folds is discussed.Engineering and Applied Science

Neizvjesnost ekonomske politike i prinos na tržištu nekretnina u Njemačkoj na primjeru bootstrap metode

The purpose of this investigation is to research the causal link between economic policy uncertainty (EPU) and the housing returns (HR) in Germany. In the estimated vector autoregressive models, we test its stability and find the short-run relationship between HR and EPU is unstable. As a result, a time-varying approach (bootstrap rolling window causality test) is utilized to revisit the dynamic causal link, and we find EPU has no impact on HR due to the stability of the real estate market in Germany. HR does not have significant effects on EPU in most time periods. However, significant feedback in several sub-periods (both positive and negative) are found from HR to EPU, which indicates the causal link from HR to EPU varies over time. The empirical results do not support the general equilibrium model of government policy choices that indicate EPU does not play a role in the real estate market. The basic conclusion is that the real estate market shows its stability due to the social welfare nature and the rational institutional arrangement of the real estate in Germany, and the real estate market also shows its importance that it has significant effect on the economic policy choice in some periods when negative external shocks occur.Svrha ovog istraživanja je ispitati uzročno-posljedičnu vezu između neizvjesnosti ekonomske politike (NEP) i prinosa na tržištu nekretnina (PTN) u Njemačkoj. U vektorskim auto-regresijskim modelima testirana je stabilnost odnosa NEP-a i PTN-a i utvrđeno je da je kratkoročni odnos između NEP-a i PTN-a nestabilan. Kao rezultat, metoda kliznog vremenskog okvira promatranja podataka (bootstrap test kauzalnosti) koristi se da bi se preispitala dinamična uzročno-posljedična veza (veza kauzalnosti) i utvrđeno je da NEP nema utjecaja na PTN zahvaljujući stabilnosti tržišta nekretnina u Njemačkoj. U većini vremenskih razdoblja, PTN nema značajan utjecaj na NEP. Međutim, značajne povratne informacije u nekoliko pod-razdoblja (i pozitivne i negativne) ukazuju na kauzalnu vezu PTN-a prema NEP-u koja varira tijekom vremena. Empirijski rezultati ne podupiru model opće ravnoteže vladine politike izbora što ukazuje na to da NEP ne utječe na tržište nekretnina. Temeljni zaključak je da tržište nekretnina pokazuje svoju stabilnost zahvaljujući socijalnoj skrbi i racionalnom institucijskom uređenju tržišta nekretnina u Njemačkoj, a isto tako i tržište nekretnina pokazuje da ima značajan utjecaj na ekonomsku politiku izbora u nekim razdobljima kod pojave negativnih vanjskih šokova

Coupled Cooling Method and Application of Latent Heat Thermal Energy Storage Combined with Pre-cooling of Envelope: Sensitivity Analysis and Optimization

This document is the Accepted Manuscript version of the following article: Xiangkui gao, Yanping Yuan, Hongwei Wu, and Xudong Zhao, ‘Coupled Cooling Method and Application of Latent Het Thermal Energy Storage Combined with Pre-cooling of Envelope: Sensitivity Analysis and Optimization’, Process Safety and Environmental Protection, first published online 9 March 2017. Under embargo. Embargo end date: 9 March 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ The version of record is available online at doi: http://dx.doi.org/10.1016/j.psep.2017.03.005 © 2017 Elsevier Ltd. All rights reserved.Cooling system for mine refuge chamber provides comfortable environment for miners to avoid heat damage. The existing cooling systems have their own application scopes and limitations. The coupled cooling method of Latent Heat Thermal Energy Storage (LHTES) combined with Pre-cooling of Envelope (PE) is a new free cooling method which is suitable for high-temperature, passive, impact and other harsh environment. Then, to improve the thermal comfort and reduce energy consumption, the effect of the pre-cooling temperature, melting temperature of PCM, aspect ratio and amounts of PCM unit on the indoor temperature are investigated in a systematic manner. Furthermore, the system is optimized and the generalized results for the evaluation parameter are given. Analysis of the results may lead to following main conclusions: (i) the method really controls the indoor temperature and the saving amount of PCM is more than 50% compared to the traditional LHTES systems; (ii) the Temperature Control(TC) performance of PCM would drop significantly if it melts more than 80%; (iii) under current operating conditions, the optimal melting temperature is about 29 °C and the aspect ratio of PCM unit is 60:500; (iv) per 1 °C the pre-cooling temperature dropped, 19% the actual amount of PCM decreased for the case studied.Peer reviewedFinal Accepted Versio