Quantum-Classical Access Networks with Embedded Optical Wireless Links

We examine the applicability of wireless indoor quantum key distribution (QKD) in hybrid quantum-classical networks. We propose practical configurations that would enable wireless access to such networks. The proposed scenarios would allow an indoor wireless user, equipped with a QKD-enabled mobile device, to communicate securely with a remote party on the other end of the access network. QKD signals, sent through wireless indoor channels, are combined with classical ones and sent over the same fiber link to the remote user. Dense wavelength-division multiplexing would enable the simultaneous transmission of quantum and classical signals over the same fiber. We consider the adverse effects of the background noise induced by Raman scattered light on the QKD receivers due to such an integration. In addition, we consider the loss and the background noise that arise from indoor environments. Decoy-state BB84 and measurement-device-independent protocols are employed for the secret key rate analysis

Gas lift optimization and flow instability

Gas lift is an artificial lift method used in the oil industry to lift reservoir fluid to the surface, by supplementing the reservoir pressure when it is depleted or insufficient. During oil production, this method can be affected by two-phase (gas-liquid) flow instability within the production tubing, which results in a reduction in the total oil recovered. There are three main flow instabilities caused by, the density wave oscillation, the casing heading pressure and the flow perturbation within the two-phase flow regime. Within this investigation of the flow structure, behaviours and instability of two-phase flow have been investigated experimentally using a high-speed motion imaging with a dedicated processing package “Dynamic studio 2015a” in a vertical transparent pipe (ID: 66 mm, Length: 2 m) thus simulating the prototype sizing of the common artificial gas lift. Numerically a Computational Fluid Dynamics (CFD) models were used with air and water as the working fluids for various cases. The experimental results demonstrated that initial bubble size plays a major role in the development and instability of the upward two-phase flow in the vertical pipe. A new Multiple Nozzle Injection Technique (MNIT) with the aim of reducing initial bubble size and distribution across the simulated vertical column was also utilised, thereby stabilising the gas lift system. Thus the present findings are compared with the current Single Nozzle Injection Technique (SNIT) (or so- called sharp-edge) that are utilised in normal gas lift operation. It has thus been manifested that the new method has the potential to increase the total oil production rate from gas lifted wells. It was found that this new injection technique reduced the overall average bubble size from 7.01 to 5.47 mm and the average overall minimum bubble size from 1.23 to 1.03 mm. The average large bubble size of the Taylor bubble was also reduced from 44.07 to 39.95 mm in the simulated pipe. This perceived to increase in production rate from 40 to 43.05 l/min, which give overall increment of 7.5% at different operating conditions. This is in comparison with the single orifice injection technique at the same operating conditions. Throughout this investigation, water was used as working fluid since the column of corresponding water in the petroleum production tubing has the highest hydrostatic pressure 0.20 bar compared with crude oil. Hence, during the gas lift process crude oil will be less cumbersome to produce than water. Moreover, it was found that when using the Multiple Nozzle Injection Technique the distribution of gas bubbles could changed from the middle of the vertical pipe (core peaking) to across the entire pipe area (wall peaking). This minimised the two-phase flow development and flow instability, even when the mixture velocity was increased. This was due to a reduction in the coalescence process of the gas bubbles as a result of improved bubble distribution when compared with the Single Nozzle Injection Technique with the same dimensions. The numerical three-dimensional CFD model using the multi-fluid volume of fluid (VOF) gas-lift with the same dimensions and operating conditions compared qualitatively with bubble distribution similar to those found by experimental trials. In addition, the pressure drop long the simulated test section was calculated numerically. It was also found that the pressure drop was reduced from 0.18 bar to 0.11 bar when the new MNIT was used as compared with the SNIT that are normally used in gas lift operation practise

Financial situation of PN17 companies listed in the Malaysian Stock Exchange

A Practice Note 17 (PN17) Company is a listed company in the Malaysian Stock Exchange that is financially distressed or does not have a core business or has failed to meet minimum capital or equity (Less than 25% of the paid up capital). Financial ratio analysis method can be used to detect the failure of this company. As of 9th August 2010, there are still thirty four companies listed on Malaysian Stock Exchange classified under PN17 List. These companies have entered into PN 17 list in accordance with existing standards. There are also investors who do not know the status of these listed companies. A real and full attention has not been given yet for these companies. Analytical studies and scientific researches are almost still lacking on PN17 Companies listed in the Malaysian Stock Exchange. The aims of this research work is to examine the differences between the financial liquidity ratios (Current, Quick, Cash Ratio) and Altman's Z-score in determining the financial failure of companies, that is using financial ratios and Altman Z Score to examine whether there is different between PN17 companies and Non-PN17 listed in the Malaysian Stock Exchange. It also aimed to determine whether are all the PN17 Companies listed in the Malaysian Stock Exchange financial failure companies, to explore and report the financial situation of companies listed on Malaysian Stock Exchange. The available data collected from the library of Malaysian Stock Exchange covering the period from 2003 to 2009 were used in the analysis. This study answered the research questions formulated. Financial Liquidity ratios and Altman Z-score can be used to detect financial distress of companies, and it is important to compare ratios with the industry average or with a competitor in the same sector. Not all the PN17 Companies are financial failure Companies, It was found that there are financial difficulties companies still listed among the Non-PN17 list. Companies should emphasize on the issue of accounting disclosure

The strategic role of GCC Islamic banks in Malaysia: a knowledge transfer perspective

The recent trend in the field of strategic management has been to emphasize the role of knowledge management as a basis of the competitive advantage of organizations. Historically, the searches for MNCs performance have been oriented around that knowledge is power. In organizations, this expression has become even more relevant than other social settings. Knowledge is a major factor that differentiates successful organizations from the unsuccessful ones. This study aims to investigate the strategic role in knowledge transfer, as well as to review the effect of strategic role as the constituent factor of knowledge transfer which contributes to the success of Islamic banking and financial knowledge performance in GCC Islamic banks subsidiaries in Malaysia. The data were collected through sending out questionnaires to 5 leaders of Upper Managers in GCC Islamic banks in Malaysia, administered 2-items of strategic roles namely: Contributor and Implementer. The respondents’ answers were subjected to SPSS. After that, semi-structured interviews were conducted with respondents. The results indicated that there is positive and significant influence of strategic leadership on knowledge transfer process. GCC Islamic banks subsidiaries in Malaysia are standing at the great extent level of strategic role from knowledge transfer perspective. In addition, the two factors named contributor and implementer lead to achieve the strategic role between headquarter and its subsidiary. The conclusion of this research paper recommended the advanced empirical research studies in future to develop a conceptual unifying model of Islamic banking and financial knowledge transfer within Islamic banks

Impact of climate change on hydropower production in Sacramento River hydrologic region

Project (M.S., Civil Engineering (Water Resources Engineering))--California State University, Sacramento, 2015.California has the most extensive water supply systems in the country. California reservoirs, more than 1000 reservoirs, play a major role in meeting the state???s water demand (ACWA, 2013). These reservoirs require careful planning and management in order to achieve the optimal balance between different demand sectors. Some of these reservoirs contribute to the state???s power supply through different hydropower plants. Beside some hydraulic and design parameters, the amount of produced hydropower is determined by amount of released water and the available storage. The amount of released water from any reservoir is a function of many factors, such as: climate, precipitation and inflows, demands and environmental requirements downstream. \ud This study examines the implication of Climate Change and Warming on Hydropower production in Sacramento River hydrological region. A simulation model of the study area is built using Water Elevation and Planning System (WEAP). Three main reservoirs for hydropower generation in the study area were included: Shasta Reservoir, Oroville Reservoir, and Folsom Reservoir. Snowpack in west upper slope of the Sierra Nevada Mountains plays a major role in the hydrology of Sacramento River basin. Studies, (Franco et al. 2011) and (Rheinheimer et al. 2014), have shown a possible increase in the California???s air temperature from 1.5 oC to 6 oC, with an expected greater impact on the upper Sierra Nevada Mountains. To assess the impact of such possible increase in air temperature, three warming scenarios were developed. The historical climate data (1964-2014) was collected for each catchment. Then for future projections (2014-2064), three air temperature increase scenarios were developed. The scenarios are 0 oC (no change, for comparison), 2 oC, 4 oC and 6 oC. Air temperature was the only parameter changed, other parameters such as precipitation remained unchanged. The result obtained from the model shows that the increase in air temperature can yield a considerable change in hydropower production. Under 6 oC increase scenario, the reduction in the total hydropower supply over the 50 years (2015-2064) was 9.43% for Shasta, 6.76% Oroville, and 6.44% for Folsom reservoir.Civil Engineering (Water Resources Engineering

Transfer of Islamic banking knowledge from GCC Islamic bank headquarter to its subsidiary in Malaysia

The Gulf Cooperation Council (GCC) Islamic banks' subsidiaries which have invested in Malaysia have seen the going gets tough. They are strapped by paltry returns and stymied by stiff competition from the local Malaysian banks. Since the increasing competition and the slowdown of the economy have encouraged multinational banks to seek new ways to improve their internal efficiency and their performance, it has given the pivotal importance of knowledge transfer for the competitiveness of multinationals, but the process of transferring knowledge effectively across dispersed units of International Islamic banks has only attracted little and rather fragmented research interest. Thus, there is hardly evidence about how this large-scale knowledge transfer has been achieved and what knowledge has actually been transferred to the GCC Islamic banks investing in Malaysia. Therefore, the aim of this research study is to develop a comprehensive Islamic banking knowledge transfer framework that serves as a basis for future research agenda. The study focused on the cases of the Islamic banks' subsidiaries in Malaysia that are fully owned by GCC Islamic banks. The respondents were the experts who are well aware of their business to answer the survey questionnaire. This study is mixed method type of research study. A survey questionnaire was used as a guideline to compose specific questions related to the conceptual model. This is followed by interviews that were conducted with the respondents to investigate the model’s constructs and then to analyse the generated propositions in order to address the main research questions. This study tested the research propositions and found that, the integration between HQ bank and its subsidiary bank, the strategic role and the ability of the subsidiary bank to engage in Islamic banking knowledge transfer are related to the development of Islamic banking knowledge transfer capabilities. Besides that, the development of Islamic banking knowledge transfer capabilities, as well as organizational and cultural distances between HQ bank and its subsidiary bank are related to the Islamic banking knowledge transfer performance. In short, the findings of this research study have not only contributed to the literature, but also provided valuable information to both managers and policy makers on the matter of transferring the knowledge of Islamic banking. The study recommends the top management to implement KT practices that need to be made known and felt by all levels of bank units' members. Managers have to pay attention to the development of communication technologies, personal contacts, training efforts and relations of trust between the employees, because it is an important factor for a successful knowledge transfer process. Finally, the findings of this study are useful, but need to be strengthened by future research work

Quantum and classical communications on shared infrastructure

Future communications networks not only should enable massive exchange of classical bits, but also the transmission of quantum bits on which many quantum applications rely. This will be the key to offering quantum technologies in a cost-efficient way, and it should encompass the integration of quantum and classical networks at the core of existing optical communications networks, as well as at the access end of such networks. In this work, we cover a range of proposals that enable such an integration for one of the imminent applications of quantum technologies, i.e., quantum key distribution (QKD), by which users can securely exchange a secret key for their cryptographic needs. This will include using wavelength division multiplexing techniques to send quantum and classical data on the same fiber as well as wireless access for QKD users to passive optical networks. In each case, we explore optimal arrangements to find the best way forward for an amicable coexistence

Finite-Key Effects in Quantum Access Networks with Wireless Links

The finite-key effects in quantum access networks are studied. We consider a quantum-classical network where each user is equipped with a certain wavelength to exchange secure keys, using quantum key distribution techniques, and another one to exchange classical data. Users are connected to the central office via a passive optical network. The quantum users are connected to the fiber links via an indoor wireless channel. We investigate the regimes of operation within which a secure key can be exchanged in a reasonable amount of time. We find out that by properly designing the system, it is possible to run both quantum and classical systems at their full capacity

Wavelength assignment in quantum access networks with hybrid wireless-fiber links

We propose a low-complexity near-optimal wavelength allocation technique for quantum key distribution access networks that rely on wavelength division multiple access. Such networks would allow users to send quantum and classical signals simultaneously on the same optical fiber infrastructure. Users can be connected to the access network via optical wireless or wired links. We account for the background noise present in the environment, as well as the Raman noise generated by classical channels, and calculate the secret key generation rate for quantum channels in the finite-key setting. This allows us to examine the feasibility of such systems in realistic scenarios when the secret key exchange needs to be achieved in a limited time scale. Our numerical results show that, by proper choice of system parameters for this noisy system, it is possible to exchange a secret key in tens of seconds. Moreover, our proposed algorithm can enhance the key rate of quantum channels, especially in high-noise and/or high-loss regimes of operation