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The Cambodian banking sector has rapidly expanded in recent decades, although there are concerns about the performance of Cambodian banks and the country’s banking sector. A paucity of empirical evidence to clarify the real issues in the banking sector also makes it difficult to formulate effective policy measures to address any potential problems. This study provides empirical evidence by estimating the cost function and efficiencies of 34 commercial banks over the period from 2012 to 2015. We find that the average cost efficiency scores range from 0.60 when measuring bank outputs as loan and deposit amounts, and 0.77 when measuring bank outputs as interest and non-interest income, suggesting that if they are operated more efficiently, they could cut costs by 40% in fund mobilization and 23% in profit making while keeping the same output level. We also find that the Cambodian banks have experienced an improvement in efficiency scores over the period for both aspects of banking activities. Furthermore, we find that expanding a branch network into rural areas is inefficient for bank management, and holding excessive liquidity is associated with higher efficiency, but diversification in bank business operations is negatively associated with cost efficiency of Cambodian commercial banks.

In this paper, we define a new class of functions, called exponentially roughly B-invex functions and discuss their properties. Optimality criteria for optimization problems involving these functions are obtained. Efficient solutions of exponentially roughly B-invex multi-objective problem are characterized by weighting approach. Also, sufficient and necessary conditions for a feasible solution to be an efficient solution for the considered multi-objective problem are derived. Finally, the Mond–Weir-type dual problem is considered under the exponentially roughly B-invexity assumption and its results are generalized for the considered optimization problems.

A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. We propose a certificateless proxy signature (CLPS) scheme, and prove it's security under a stronger security model. Although some good results were achieved in speeding up the computation of pairing function in recent years, it is still interesting to design cryptosystem with less pairing operations. Taken into account the computational costs, our scheme only requires 2 pairing operations in delegation and signing, respectively.

A three-detector measuring system making use of a pure-Ge detector combined with two Si(Li) detectors has been developed. The efficiency curve of the pure-Ge detector has been determined easily as relative efficiencies to those of the existing Si(Li) detectors, since this system allows us to analyze a sample with the pure-Ge and the Si(Li) detectors simultaneously under the same irradiating conditions. It is found that detection efficiencies of the pure-Ge detector decrease just above the absorption edge of Ge owing to absorption of X-rays in the dead layer of the detector. Accuracy of the efficiency curve thus obtained was confirmed by analyzing a few samples whose elemental concentrations are known. It is confirmed that a pure-Ge detector can be used in place of a Si(Li) detector for the purpose of analysis of elements Z ≧ 19, since its energy resolution is almost equal to that of a high-performance Si(Li) detector and efficiencies at high energies are far better. Moreover, it becomes possible to detect prompt γ-rays and to analyze light elements such as fluorine, which arouses much interest from the point of view of environmental contamination. Detection limit of fluorine is found to be less than 0.1 ppm for water samples.

A new method has been developed for determining detection efficiency of a Si(Li) detector, which is one of the most important quantities in PIXE analysis. In this method, targets prepared by smashing crystals of several chemical compounds into fine pieces and by sprinkling them onto a thin polypropylene film are measured in same experimental condition as in PIXE analysis, and relative efficiency curves are obtained for two Si(Li) detectors. These results are compared with those from theoretical calculations. New efficiency curves are obtained by regarding thickness of the Be window, the Si dead layer, the gold contact and ice layer as variable parameters and practical thicknesses of them are estimated. It is found that these efficiency curves give quantitatively fairly accurate values when they are used for data analysis from NIST bovine liver even in cases of Na and Mg.

It is demonstrated in this work, that PIXE is a good mass indicator for suspended particles in urban environments. Results are presented for several samplings performed in urban and other environments in Chile and other countries. Aerosols were collected on filters operated by a Stacked Filter Unit (SFU) in the range of particles < 15 µm (PM₁₅) and < 10 µm (PM₁₀), mainly the respirable fraction. For samplings performed in downtown Santiago, the sum of the concentrations of the elements detected by PIXE correlated well with the indices of respirable suspended particles (RSP) measured by gravimetry. There was no high correlation for other samplings, near a crushing plant and near mineral storage. On the average, the sum of the PIXE results for Santiago’s aerosols represents about the 15% of the total mass collected in the respirable fraction. A measurement of collection efficiency for the 0.4 µm Nuclepore filter was performed by means of PIXE and gravimetry. These results were η_PIXE=0.98 and η_balance=0.96, for the PIXE and the gravimetric method.

Efficiency droop and green gap are terms that summarize performance limitations in GaInN/GaN high brightness light emitting diodes (LEDs). Here we summarize progress in the development of green LEDs and report on time resolved luminescence data of polar c-plane and non-polar m-plane material. We find that by rigorous reduction of structural defects in homoepitaxy on bulk GaN and V-defect suppression, higher efficiency at longer wavelengths becomes possible. We observe that the presence of donor acceptor pair recombination within the active region correlates with lower device performance. To evaluate the aspects of piezoelectric polarization we compare LED structures grown along polar and non-polar crystallographic axes. In contrast to the polar material we find single exponential luminescence decay and emission wavelengths that remain stable irrespective of the excitation density. Those findings render high prospects for overcoming green gap and droop in non-polar homoepitaxial growth.

The Tantalum oxide material (Ta₂O₅) as tunnel oxide in comparison with the Silicon dioxide (SiO₂) Tunnel oxide is proposed. The lower bandgap and high refractive index of Ta₂O₅ has several advantages over SiO₂. The Ta₂O₅ is used as Anti-Reflecting coating earlier, but also has capability to behave as the tunneling oxide. In the ultrathin region, the Tantalum oxide (Ta₂O₅) potentially produces extremely high tunneling and high electric field. The greater electrical intensity increases both the transportation of carrier and passivation quality of designed c-Si structure. The carrier selectivity is also increased due to very high capacitive nature. The performance measurement is done in ASTM certified AM1.5G environment using Silvaco ATLAS 2D TCAD tool. The comparison has been made between Ta₂O₅ and SiO₂, to show the advantage of Ta₂O₅ over SiO₂. The lower bandgap of 4.8eV and higher affinity of 3.19 of Ta₂O₅ as compared to SiO₂ proves to be better material as tunneling oxide. The bandgap and electric field region of both the materials have been studied. In first approach to use Ta₂O₅ as tunneling oxide, the power conversion 28.42% is obtained for 0.1nm thickness of the Ta₂O₅. External and internal quantum efficiencies are well above 80% and 90% respectively. The characteristics of the Ta₂O₅ tunneling based solar cell are compared with the previous reported solar cell.

We study the searching efficiency of complex networks considering node's visual range within which a node can see its neighbors and knows the topology. We firstly introduce the network generating models and searching strategies. Using the generating function method, in both random networks and scale-free networks we derive the most-effective-visual-range (MEVR) which means every step of random walkers can find most of new nodes and we also obtain the searching-cost (SC) under visual range. To validate the generating function method, we perform simulations in random networks and scale-free networks. We also explain why the deviation between numerical simulation and theoretical prediction in scale-free networks is much larger than that in random networks. By studying the visual range of nodes in the networks, the results open the possibility to learn about the searching on networks with unknown topologies.

This paper investigates the degree of congestion and efficiency in complex traffic networks, by introducing congestion effects, which can be described by flow-based link cost functions. Different network topologies including random networks, small-world networks and scale-free networks are explored. The impact of different distributions of capacity and origin-destination traffic demand on the degree of congestion and efficiency in complex networks is mainly studied. A phase transition from free flow state to traffic jams can be uncovered. The relationship between congestion and efficiency in complex networks is also discussed.

In the presence of buoyancy, multiple diffusion coefficients, and porous media, the dispersion of solutes can be remarkably complex. The lattice-Boltzmann (LB) method is ideal for modeling dispersion in flow through complex geometries; yet, LB models of solute fingers or slugs can suffer from peculiar numerical conditions (e.g., denormal generation) that degrade computational performance by factors of 6 or more. Simple code optimizations recover performance and yield simulation rates up to ~3 million site updates per second on inexpensive, single-CPU systems. Two examples illustrate limits of the methods: (1) Dispersion of solute in a thin duct is often approximated with dispersion between infinite parallel plates. However, Doshi, Daiya and Gill (DDG) showed that for a smooth-walled duct, this approximation is in error by a factor of ~8. But in the presence of wall roughness (found in all real fractures), the DDG phenomenon can be diminished. (2) Double-diffusive convection drives "salt-fingering", a process for mixing of fresh-cold and warm-salty waters in many coastal regions. Fingering experiments are typically performed in Hele-Shaw cells, and can be modeled with the 2D (pseudo-3D) LB method with velocity-proportional drag forces. However, the 2D models cannot capture Taylor–Aris dispersion from the cell walls. We compare 2D and true 3D fingering models against observations from laboratory experiments.

Exploiting the computing power of the diversity of resources available on heterogeneous systems is mandatory but a very challenging task. The diversity of architectures, execution models and programming tools, together with disjoint address spaces and different computing capabilities, raise a number of challenges that severely impact on application performance and programming productivity. This problem is further compounded in the presence of data parallel irregular applications.

This paper presents a framework that addresses development and execution of data parallel irregular applications in heterogeneous systems. A unified task-based programming and execution model is proposed, together with inter and intra-device scheduling, which, coupled with a data management system, aim to achieve performance scalability across multiple devices, while maintaining high programming productivity. Intra-device scheduling on wide SIMD/SIMT architectures resorts to consumer-producer kernels, which, by allowing dynamic generation and rescheduling of new work units, enable balancing irregular workloads and increase resource utilization.

Results show that regular and irregular applications scale well with the number of devices, while requiring minimal programming effort. Consumer-producer kernels are able to sustain significant performance gains as long as the workload per basic work unit is enough to compensate overheads associated with intra-device scheduling. This not being the case, consumer kernels can still be used for the irregular application. Comparisons with an alternative framework, StarPU, which targets regular workloads, consistently demonstrate significant speedups. This is, to the best of our knowledge, the first published integrated approach that successfully handles irregular workloads over heterogeneous systems.

We present an implementation of Global-Flush Primitives using counters. This implementation costs comparable to the most lightweight implementation of causal ordering. Thus, at a comparable cost, the presented implementation enriches functionality compared to causal ordering; as Global-Flush Primitives permit making an assertion about messages sent in the past of sending m, in the future of sending m, about both, or neither, where the past and the future of an event is defined using the relation "happened before." Using Global-Flush, a message can be sent to any subset of processes specified as a parameter.

From 1979, the Singapore government started to transform the nature of secondary education in Singapore. In 1979, nine schools were chosen as Special Assistance Plan (SAP) schools. After the call towards reforming the school system in the 1980s, the development of Independent schools evolved. In 1994, a new category — the autonomous school — was established. Besides reforming the school structure, in 1992, the "ST Schools 100" (first published by The Straits Times on 19 August 1992) started to rank the top 50 schools in the Special/Express stream and the top 40 schools in the Normal stream, along with separate tables listing the top value-added schools in both streams. Until quite recently, this ranking scheme had been endorsed by the Ministry of Education since 1992 and published on their website annually since 1995. This paper looks at how these new initiatives have affected secondary school outcomes. Comprising a panel data set of 30 of the top 50 schools in Singapore over the 1991–2001 period, the study looks at the technical efficiency of schools as a response to the introduction of new initiatives using two methodologies. The first baseline approach is that of a Corrected Ordinary Least Squares (COLS) multiple-output distance function. The second methodology used is the technical efficiency frontier effects model as described by Battese and Coelli (1995) and Coelli and Perelman (1996) which is a maximum likelihood estimation technique.

By the end of the 1990s, the Singaporean government had recognised the need to open up its banking sector so as to remain competitive in the global economy. The Monetary Authority of Singapore (MAS) thus began deregulation of the banking sector in 1999 to strengthen the competitiveness of local banks relative to their foreign competitors through mergers. This paper employs a nonparametric Malmquist productivity index to provide measure of productivity, technological change and efficiency gains over the period 1995–2005. The findings reveal some total factor productivity growth associated with deregulation and scale efficiency improvement largely from mergers amongst the local banks.

It has been stated that the meaning of higher efficiency is equivalent to being more competitive and profitable for enterprise operations. Using insights from fundamental analysis, the purpose of this study is to investigate the relative operational performance and market efficiency of liner shipping firms. The paper applies Data Envelopment Analysis (DEA) to calculate an efficient frontier that corresponds to the optimal relationship between financial data and market value. Stocks at the frontier are optimally priced in the market. Stocks falling behind the frontier are valued less favorably. The models developed incorporate inputs and outputs related to operating performance and market efficiency consistent with the prior financial accounting literature. Our sample consists of 18 major (leading) international liner shipping firms that have been found to exhibit average market efficiency and a high degree of operational performance.

We develop a simple model with endogenous rural–urban migration to analyze the implications of migration restrictions for economic welfare. The model reveals that a combination of an efficient urban bias in public service provision and internal migration restrictions can raise social welfare. Our results suggest that migration restrictions should be carefully assessed as a policy choice rather than immediately dismissed as suboptimal. However, even when restrictions raise social welfare, they increase urban households’ welfare at the expense of rural households’ welfare, creating an equity tradeoff for policy-makers to consider.

Given considerable changes in the Vietnamese banking environment brought about by significant reforms towards liberalization during the last two decades, this study investigates the evolution of competition and efficiency, compares the competition and efficiency of state-owned banks to joint-stock banks, and then tests the “quiet life” hypothesis in this industry over the period 2000–2014. This study employs the efficiency-adjusted Lerner index (i.e., market power) to capture competition, and the cost efficiency estimated by a Fourier-flexible function stochastic frontier analysis (SFA) to capture bank efficiency. This study firstly finds a slight improvement of competition and cost efficiency in the Vietnamese banking sector over the analysis period. Secondly, there are no significant differences in competition and cost efficiency level between state-owned and joint-stock banks. Thirdly, a positive causality running from competition to cost efficiency is documented, providing evidence of supporting the “quiet life” hypothesis. Finally, positive efficiency effects of the banks’ capital ratio and size are found, while insignificant impacts of the growth of GDP per capita and 2007 global financial crisis were observed. The results are strongly robust to a variety of tests. The findings suggest pro-competition, pro-capitalization and pro-size expansion policies in the Vietnamese banking sector if targeting at improving the cost efficiency of Vietnamese banks.

We investigate the impact of organizational form on operational efficiency using a large sample covering manufacturing and non-manufacturing sectors in the United States over 30 years. We quantify operational efficiency using various measures, and find robust evidence that segments of diversified firms are operationally more efficient than their single-segment industry peers. The difference is more noticeable in industries where financing needs are high due to greater growth potential and where access to external markets is constrained due to higher information asymmetry.

The reallocation of resources from low- to high-productivity firms can generate large aggregate productivity gains. The paper uses data from the Malaysian manufacturing censuses of 2005 and 2010 to measure the country’s hypothetical productivity gains if all misallocation within industries are removed. Comparing the results across the two census waves, we conclude that efficiency gaps (that is, the degree of misallocation) in Malaysia have narrowed by one-fifth. The efficiency gaps, however, appear to be over 40%, indicating a substantial room for improvement. This is important, particularly if total factor productivity growth is expected to support future economic growth. The analysis in this paper accounts only for resource misallocation within sectors. There may be other, possibly large, resource misallocation across sectors. Closing those gaps could boost total factor productivity and gross domestic product growth even further.