bluuebunny/crossref_metadata_2025 huggingface dataset:
The design of the idea network management platform
Authors: Penna Manoel Camillo
Published: July 2007

This article describes the design of the IDEA network management platform which is to provide a general solution for constructing network management systems over heterogeneous and distributed environments.
The wrong fallback switch can be costing you money
Authors: Kelly Bob
Published: July 2007

Communications Devices of Clifton, NJ, has a family of AMS switches (Automatic Management Switch) that contains a microcontroller, an additional network management port and a calendar/clock. These cost‐saving features provide the user with programming capability, extensive report generation and a variety of alarm conditions and operating flexibility.
A Detailed Look into Net Expert
Authors: DeSousa Karen E.
Published: July 2007

Net Expert is an integrated network management software package designed to manage and control large, eclectic, multi‐vendor, multi‐protocol wide area networks under a single, uniform user interface, with or without standards.
Global telecommunications tariffs: Using worldnet to design international networks
Authors: Bauer Matthew B.
Published: July 2007

In the USA, where we have enjoyed the fruits of competition in the telecommunications sector for almost ten years, access to timely and accurate tariff information has played a key role in the development of the industry.
Improved Reconfiguration Algorithm for the Dual Ring Network by Token Reversal
Authors: Chakraborty Rabindra Nath , Yaprak Ece
Published: July 2007

An improved algorithm is proposed to further enhance the reliability of the dual‐ring network over the existing reconfiguration algorithm in the case of topological alteration due to link failures. The improvement is caused by accommodating the reversal of token flow instead of the loopback operation.
Management of osi and tcp/ip networks: Integrated management with os/eye*node
Authors: Jones Dr Katherine
Published: July 2007

Managing a network, large or small, is not a trivial task: today's networks contain heterogeneous computers and network devices; deal with different carriers across the wide area; connect widespread sites; and use a variety of different protocols through which to communicate data.
The equipment evaluation process: A methodology for success
Authors: Held Gilbert
Published: July 2007

In this article we will examine the use of a four‐phase approach for performing the equipment evaluation process. By following this approach you will obtain knowledge of evaluation elements to consider as well as a mechanism for combining technical and cost evaluations in order to select a product that represents an optimum level of price and performance.
Applying simulation to network planning and design issues
Authors: Jazwinski Andrew , Laszakovits Brian
Published: July 2007

What is simulation good for and how do you use it? Simulation can be applied to a wide variety of network planning and design issues. This paper describes a number of such issues of interest, suggesting the most relevant simulated performance and the benefits derived from a simulated network performance analysis and then demonstrates the simulation technology through a detailed case study using Plan NetTM.
Connectionless service in an atm‐based network
Authors: Killat U.
Published: July 2007

With the advent of connection‐oriented broadband in the B‐ISDN, the question arises as to how can computers, founding their communication needs on MAC service, profit from the new communication infrastructure? This paper describes the answers by the CCITT to this question and outlines some of the problems to be overcome. Finally, new attempts for the provision of the Connectionless Service are presented.
Token ring network management: Configuration management
Authors: Nilausen Jesper
Published: July 2007

In this fourth article in the series on Token Ring Network Management we will discuss selected areas of relevance to today's Token Ring networking environment.
Token ring network management: Change management
Authors: Nilausen Jesper
Published: July 2007

This article, which is the fifth in the series on Token Ring Network Management, will discuss selected aspects of Change Management that are relevant in today's Token Ring networking environment.
Empowering Net Ware With REXX
Authors: Shepherdson Lew
Published: July 2007

Until now, the full power and flexibility of Net Ware could only be exploited by skilled C programmers using very non‐trivial software development kits with compilers, linkers and debuggers specifically engineered to run under Net Ware. This all changed with the recent addition of REXX into the Net Ware toolkit, which provides administrators, power users, and application developers with access to all the power of Net Ware.
Design and Implementation of a Composite Performance Evaluation Model for Heterogeneous Network Management Applications
Authors: Havel Olga , Patel Ahmed
Published: July 2007

This article examines the place of analytical models in realtime performance management applications. The main objectives are to define, specify and implement a system based on a composite model that provides the optimal software environment for performance analysis and tuning of heterogeneous networks.
Token ring network management: Performance management
Authors: Nilausen Jesper
Published: July 2007

In this sixth (and final) article in the series on Token Ring Network Management we will discuss Performance Management, which is relevant for many parts of the distributed Token Ring environment
Private and Authentic Communication in Passive Optical Networks
Authors: Heister U. , Killat U.
Published: July 2007

Broadband access systems based on Passive Optical Networks (PONs) present a cost‐effective alternative to star‐shaped ones. An inherent weakness of PONs lies in their tree topology. This article identifies the measures necessary to support private and authentic two‐way communication via a passive tree.
Contingency Planning in LAN/WAN Environments
Authors: Jones Katherine
Published: July 2007

When a disaster recovery plan (DRP) is in place in a company, it is often solely for the mainframe; too often no attention is paid to the departmental distributed servers.
Information networks awareness and utilization issues: The case of gulfnet
Authors: Taher Hasan , Bakry Saad Haj , Al‐Dhalaan Abdullah , Al‐Muammar Abdulaziz
Published: July 2007

This article addresses the awareness promotion‐utilization of services problem within the framework of the diffusion of innovation theory, and with respect to information networks, specifically in the case of GULFNET
Adding value to MIBs: A relationship layer for management platforms
Authors: Clemm Alexander
Published: July 2007

The provision of a relationship layer component inside management stations is suggested that simulates advanced relationship concepts by providing an according view on existing, conventional management information.
Managing Diverse Environments with CA‐UNICENTER for UNIX
Authors: Jones Katharine
Published: July 2007

A critical component in selecting platforms to replace or augment proprietary minicomputers or mainframes in the enterprise is their ability to be managed, both as stand‐alone systems and as nodes distributed across a local or wide area network.
The World Trade Center Disaster and the Lessons Learned
Authors: Nachsin Cynthia K.
Published: July 2007

For NYNEX, the lessons learned from the explosion and fire in the World Trade Center were both positive and negative.
Planning Disaster Recovery Protection
Authors: Berman Al
Published: July 2007

The era of the LAN has been marked by local responsibilities and autonomous control. While this may have been acceptable during the early stages of development, it is becoming obvious that there need to be standards and controls placed upon this environment.
A new era in data network security: Protocol‐sensitive encryption
Authors: Peterson Dale G.
Published: July 2007

A protocol‐sensitive security solution becomes a security overlay on top of a data communications network. No modification or access to the data network is required and, if implemented properly, users are unaware that their data is being secured.
Architecture and Performance Comparison of High‐speed Switch Networks
Authors: Haca Anno , Yur Veronique
Published: July 2007

This paper evaluates and analyzes performance of the growable switch, bypass queue switch, and tandem banyan switch in ATM networks.
Recent progress in research and development of crystalline silicon solar cells in Japan
Authors: Saitoh Tadashi , Shimokawa Ryuichi , Hayashi Yutaka
Published: July 2007

Recently, the research and development of crystalline silicon solar cells in Japan has greatly advanced. Fundamental research has been conducted on the recombination and passivation of minority carriers at Si/SiO2 interfaces and in those bulk regions containing grain boundaries. Qualities of silicon feedstock and substrates have been improved and large‐area cell efficiencies using Czochralski single and cast polycrystalline substrates have reached 20% and 17%, respectively, by using low‐cost cell fabrication processes. Such high efficiency values are realized by tenacious improvement of substrate quality and the development of new processes for fabricating solar cells.
Solar cell efficiency tables
Authors: Green Martin A. , Emery Keith
Published: July 2007

One regular feature planned for Progress in Photovoltaics is the publishing of solar cell and module efficiency tables summarizing the highest independently confirmed results for different technologies. These tables are expected to be of interest not only to researchers directly involved in these areas but also to those less directly involved but interested in being kept informed of the latest results with each of the different technologies or interested in an authoritative summary of these results. Other desirable outcomes may be the encouragement of research results and the further simulation of intercomparison of measurements between disignated cell test centres. Guidelines for inclusion of results into these tables are outlined and the first set of tables of results conforming to these guidelines are published.
Recent progress in thin‐film cadmium telluride solar cells
Authors: Chu Ting L. , Chu Shirley S.
Published: July 2007

Cadmium telluride (CdTe) with a room‐temperature bandgap energy of 1.45 eV has been shown to be the most promising low‐cost, thin‐film photovoltaic material for terrestrial applications. Significant progress has been made during the past several years, and thin‐film CdTe solar cells of > 1 cm2 area with conversion efficiencies higher than 12% have been prepared by several techniques. Thin‐film CdTe photovoltaic modules with 10% efficiency have also been produced. They are of the heterojuntion configuration using a transparent conducting semiconductor (TCS) as the window and p‐CdTe as the absorber. In this paper, the potential window materials for thin‐film CdTe solar cells are discussed. Thus far, cadmium sulphide (CdS) with a bandgap energy of 2.42 eV at room temperature has been found to be best suited for efficient CdTe solar cells. the deposition techniques for p‐CdTe films capable of producing efficient solar cells, including close‐spaced sublimation (CSS), electrodeposition, screen printing and spraying, are briefly reviewed, and the characteristics of the resulting solar cells are discussed. It is concluded that the efficiency of thin‐film CdTe solar cells can be increased to 18‐19% in the near‐term, leading to 15‐16.5% efficient modules.
The ‘Alpsolar’ Project—Field testing and optimization of European photovoltaic power plant equipment at high‐elevation and nordic sites
Authors: Nentwich A. , Szeless A.
Published: July 2007

The ‘Alpsolar’ Project, which forms part of the international European ‘Eureka’ programme, is a cooperative venture between three electrical power utilities based in Austria, Finland and Germany. Its main task is the field testing and optimization of remote‐controlled, grid‐connected, photovoltaic (PV) power plants at high‐elevation and nordic sites, with the aim of bringing such plants to commercial viability. This paper describes the background, overall deisgn and operation of the three plants, and reports initial operating experience over 1‐3‐year periods in the areas of solar module, inverter and plant efficiencies; plant availability and electricity yield; monitoring and control; maintenance and repair; and economics.
The role of silicon solar cell fabrication in intermediate‐level PV training
Authors: Marques F. C. , Chambouleyron I.
Published: July 2007

Appropriate regionally‐based training is of major importance for improving the market penetration of basic PV systems in developing countries. This communication describes an initiative at a Brazilian university where science and engineering undergraduates are encouraged to fabricate, test, and package crystalline silicon solar cells.
Phased development of high‐concentration photvoltaic modules
Authors: McNaughton W. P. , Cummings R. D. , Dostalek F. J. , Richman R. H.
Published: July 2007

During the 1970s and early 1980s a promising solar cell technology evolved under contract with the Electric Power Research Institute. the work produced a point‐contact photovoltaic cell technology that has established a numer of world record achievements during its 15‐year development. In 1984 a conceptual design was proposed for a cell package, module and array system for use in utility‐scale commercial power production.

Since 1984 the laboratory concept has been moved forward toward commercial application. the design and processing of the cell has progressed from laboratory device research toward a mass‐produced product, with concurrent reduction in cost and improvement in uniformity. A number of inadequacies have been confronted and eliminated.

A progressive design philosophy for the production of cell packages, modules and arrays has been invoked and implemented. an extensive test programme to determine module and array performance and reliability has been put in place. More than 2500 functional high‐concentration cells have been produced in the evolutionary process. Approximately 800 of those cells have been installed in fully operational modules for filed tests. Over 130 modules have been constructed and are in field testing for electrical, structural, thermal or weathering tests. Two full‐sized array structures (each containing 60 instrumented ‘thermal’ modules) have been constructed and continue to undergo field testing for alignment, performance and reliability.

This paper reviews the design, construction and testing of modules, which is a part of the programme that has been central to the overall commercialization effort. the progressive module philosophy is reviwed and key challenges that have confronted the development of a commercial system are discussed. Results are included from more than 6 years of testing, including over 250 000 h of field exposure on individual test modules and over 2 000 000 exposure hours on all modules in the prgramme.
An energy consumption scenario for sizing rural electrification PV systems
Authors: Eyras J. R. , Lorenzo E.
Published: July 2007

This paper submits a systematic analysis of user consumption patterns of several photovoltaic (PV)‐powered rural dwellings in a Mediterranean area of Spain. the measurements have been carried out within the framework of two projects and assessed in contrast with other experiences. This analysis allows a consumption scenario developed previsouly to be tested by means of the classification of families according to the number and age of their members into three types—extended, mean and reduced—with the aim of establishing a few standard cases of optimization for sizing purposes.

Because the use of AC current is indispensable, at least for domestic appliances, the scenario hereby proposed leads to PV system sizes of 160, 320 and 480 Wp for reduced, mean and extended families, respectively, enjoying a level of comfort similar to grid‐conneced systems.
Evaluation of the steady‐state photocarrier grating technique with respect to A‐Si: H and its application to A‐Si1–X GeX: H alloys
Authors: Abel C.‐D. , Bauer G. H.
Published: July 2007

The steady‐state photocarrier grating technique is analysed with respect to deviations from local charge neutrality. We present a generalized expression for the normalized photoresponse β as a function of the grating period as well as of the external electric field; the transport is characterized in the sense of bipolar and ambipolar, diffusion and drift displacement, respectively. Experimental data for undoped a‐Si: H, especially the variation of the β coefficient with the external electric field, are discussed and fitted by the generalized equation. the effective dielectric relaxation time, which takes the trapped photogenerated majority carriers into account, is found to be responsible for ambipolar transport in undoped a‐Si: H in the low electric field regime. Further, the μτ‐products of electrons and holes in a‐Si1‐x Gex: H alloys are deduced experimentally. the low‐gap alloys are an appropriate candidate for photovoltaic applications.
Computer simulation of enhanced output from bifacial photovoltaic modules
Authors: Chieng Y. K. , Green M. A.
Published: July 2007

A bifacial photovoltaic module can collect not only the light falling directly on its front but also light incident on its rear after reflection from natural surroundings, called the albedo reflection, and light scattered from the sky itself. the benefits of such bifacial response are analysed by modifying a standard computer photovoltaic simulation software package (PVFORM version 3.3). Results obtained from computer simulation and field experiments show that, without any special features, there is about a 20% increase in the total annual energy generated by a bifacial panel compared to a monofacial panel. There are also summer peaks caused by the morning and evening light falling directly on the rear side of the panel. This means that the bifacial panel allows extended operation during summer. There is also a slightly smaller reduction in relative output power for the bifacial module on cloudy days.
Optimization of decentralized hybrid electrical energy systems (with photovoltaics) for typical villages in the North Indian plains
Authors: Sodha M. S. , Chandra Ram , Rana Santosh
Published: July 2007

This paper presents an analysis of an optimal decentralized mix of photovoltaics, biogas generation and biomass gasifier generation, to meet the electrical energy demand of typical villages in the North Indian plains. the optimal mix preserves existing patterns of fertilizer application and cooking and also corresponds to minimum cost. Survey data for four villages have been used for a numerical appreciation of the results. It is seen that the optimal energy strategy consists of meeting as much demand as possible by biogas generators using dung and meeting the rest of the demand by an optimal combination of biomius gasifier generation and photovoltaics. the cost of electrical energy with such decentralized systems lies between Rs. 2.2 per k Wh and Rs. 8.9 per k Wh for different villages (US $1 = Rs. 30). It is seen that locally availble fuel (dung and agricultural waste) is insufficient for electrical generation and the balance has to be met by photovoltaics. Rising electrical demand in coming years means that pliotovoltaics will be an increasingly important component of such optimal systems.
Event report: Sunrayce 93: Collegiate competition introduces American public to photovoltaics
Authors: Basore Paul A.
Published: July 2007

Thirty‐four university teams raced their solar‐powered cars from Texas to Minnesota during the week of the summer solstice, 20‐26 June 1993. the event, called Sunrayce 93, was a dazzling display of creativity and ingenuity by some of the brightest students in North America. Organized by the United States Department of Energy as an educational programme for college‐level science and engineering students, the race also serves to introduce the public to photovoltaics, electric vehicles and energy efficiency.
Considerations in the design of a one‐axis tracking photovoltaic system
Authors: Lorenzo E. , Macagnan M. H.
Published: July 2007

With the growing construction of large grid‐connected photovoltaic plants, the need to maximize energy collection and reduce costs is obvious. the use of tracking systems permits not only the maximization of energy collection but also a gain in the efficiency of DC to AC conversion. Nevertheless, when compared with stationary systems the literature points out some disadvantages, such as increased expense and more shadowing losses (or greater land area requirement). In this work we examine some alternatives regarding the electrical configuration of the panels for north‐south horizontal axis tracking. the choice of the best alternative produces similar results in terms of ground cover ratio, shadowing factor and costs when compared with stationary systems.
Optimum battery configuration for maximum utilization of photovoltaics
Authors: Casacca Margaret A. , Salameh Ziyad M. , Capobianco Maria R. , Losch Ross
Published: July 2007

Various photovoltaic (PV)‐powered battery storage configurations are analysed to determine if the percentage of available energy stored in the battery can be improved. Both deep‐cycle and shallow‐cycle lead‐acid batteries are considered. Computer simulation techniques are used to model the characteristics of the PV array, daily loads and environmental conditions. Three configurations were tested: one 60 ampere‐hour (Ah) battery, two 60 Ah batteries in parallel and two 60 Ah batteries that switch between the PV array and the load. Results show that the conventional PV‐powered configuration, where one battery is charged, wastes enormous amounts of energy by reaching a charged state while the PV array can still provide energy. A dual battery system enables the excess energy to be shunted into the battery under load while concurrently ensuring that one battery is constantly under charge until a full state of charge is achieved.
Silicon solar cells: The ultimate photovoltaic solution?
Authors: Green Martin A.
Published: July 2007

In the past, there has been a tendency to regard silicon cells as a stop‐gap ‘workhorse’, providing a photovoltaic presence in the market but with displacement by a more ideal technology being inevitable. Developments over the past decade encourage a re‐evaluation of this conception.

This paper explores the proposition that, rather than being a stop‐gap, silicon has the potential to become the ultimate photovoltaic solution. Strengths relative to other emerging photovoltaic technologies are outlined, as are three alternative, and possibly complementary, routes for future evolution of the technology. the strengths lie in the presently established market position, the on‐going improvements to the technology and the remaining scope for future improvement and the sustainability of silicon‐based technology. the three possible routes for future evolution are the on‐going development of present bulk substrate approaches, the use of silicon cells in concentrators ranging from low‐concentration stationary systems to high‐concentration tracking systems, and thin‐film silicon technology.
Future use of silicon solar cells in extraterrestrial applications
Authors: Iles Peter A.
Published: July 2007

This paper discusses future extraterrestrial applications for which crystalline silicon solar cells can be used. Current operating requirements for cells in space are discussed, and the range of future space missions is reviewed to select those missions where silicon cells can be used successfully.

The decision to use silicon cells will not be based on technical considerations alone. It is necessary also to consider other factors that will affect the decision, including detailed user requirements, proven performance for production cells and competition from other cell designs. We have indicated some areas of development that will help facilitate the use of silicon cells.
Microcharacterization of CdTe films deposited by close‐spaced sublimation
Authors: Matson R. J. , Hasoon F. S. , Jones K. M. , Al‐Jassim M. M. , Tomlinson R. D.
Published: July 2007

Microcharacterization of the luminescent, structural, electrical and topographical properties of thin films of close‐spaced sublimation (CSS)‐fabricated CdTe was performed. the film morphology was found to be dependent on the film thickness, deposition conditions and post‐deposition treatment. the complementary use of electron beam‐induced current (EBIC) and cathodoluminescence (CL) analysis in the scanning electron microscope demonstrated large inter‐ and intragrain inhomogeneities in the luminescent and electrical properties of the films. Follow‐on plan‐view examinations with the transmission electron microscope revealed varying densities of structural dejects, such as stacking faults and threading dislocations, which could explain the variations observed in the CL and EBIC images. Consisting primarily of experimental observations and comments, this report is phenomenological in nature.
Reduced temperature coefficients for recent high‐performance silicon solar cells
Authors: Zhao J. , Wang A. , Robinson S. J. , Green M. A.
Published: July 2007

The PERC cell (passivated emitter and rear cell) and PERL (passivated emitter and rear locally‐diffiused) cell have recently demonstrated improved cell performance owing to the high quality of surface passivation and high bulk carrier lifetimes. the effect of temperature on the performance of these cells is reported. As anticipated, owing to higher open‐circuit voltages these cells should have a lower temperature sensitivity of performance. the PERL cells demonstrated a normalized efficiency temperature variation of −2632 ppm °C−−1, which is the lowest ever reported for a silicon cell. However, PERC cells with a similarly high open‐circuit voltage showed a higher temperature sensitivity owing to the bulk resistance component, which limits the performance of PERC cells.
Photovoltaics as a demand‐side management technology: An analysis of peak‐shaving and direct load control options
Authors: Byrne John , Hegedus Steven , Wang Young‐Doo
Published: July 2007

For photovoltaic (PV) technology to play an increasing role in the utility sector at its present price, the technology needs to be developed in a manner that is consistent with, and takes advantage of, the economics of the demand‐side management (DSM) market. High‐value applications in this direction are for photovoltaics to perform a DSM function either as a direct load control (DLC) device or as a peak‐shaving option, which has the effect of raising the end‐use efficiency of customers' electrical equipment. This paper describes two PV‐DSM applications involving a water heater and an air conditioner studied at a residential PV test facility, Solar One House, located on the campus of the University of Delaware. A single 55‐W PV module directly connected to an electric water heater was found to offset standby and mixing losses, resulting in a 2°C increase in water temperature at the end of the afternoon compared to the standard DLC (grid‐disconnected) case. A conservatively sized PV array without storage could meet the house air‐conditioning load over 97% of the time from noon to 3 p.m., but only 69% from 3 p.m. to 6 p.m. If a PV system is combined with an air‐conditioning cycling program, success rates for supply of an air‐conditioning load are greatly increased, meeting almost 100% of the load between noon and 3 p.m. and 85% during 3 p.m. to 6 p.m. Furthermore, our results suggest that a modest‐size PV array with storage could significantly shave peak air‐conditioning loads during 3 p.m. to 6 p.m., thus reducing the peak demand faced by a utility. Preliminary analyses support the economic compatibility of a PV system as a DLC device or a peak‐shaving tool.
The MONOCHESS project: Goals and results to date
Authors: Luque A.
Published: July 2007

The MONOCHESS consortium, formed in the framework of the JOULE programme of the European Union, is presented. Its goal is the cooperation between laboratories and companies for the development of cheaper monocrystalline silicon 1‐sun and concentration cells. Objectives and key results already achieved are described.
High‐eficiency silicon solar cells: Si/SiO2, interface parameters and their impact on device performance
Authors: Aberle A. G. , Glunz S. W. , Stephens A. W. , Green M. A.
Published: July 2007

This article presents the first measurements of the parameters of the Si/SiO2, interfaces employed on the record‐efficiency silicon solar cells made at the University of New South Wales (UNSW). the UNSW oxides are characterized by very low values of the surface state density (∼4 × 10−9cm−−2eV‐−−1), low values for the positive fixed oxide charge density (∼7 × 10−10cm−−2) and a pronounced asymmetry in the capture cross‐sections of electrons and holes. Using the microwave‐detected photoconductance decay method, we verify experimentally that these oxide parameters produce a strong dependence of the effective surface recombination velocity at oxidized p‐type silicon surfaces on the excess electron concentration within the wafer. In high‐performance silicon solar cells, this phenomenon produces a long‐wavelength spectral response that strongly depends on the bias light intensity, a characteristic ‘hump’ in the dark current‐voltage characteristics and fill factors that are lower than would be expected from the high open‐circuit voltages of 700 mV.
Accelerated publication 16.4% total‐area conversion efficiency thin‐film polycrystalline MgF2/ZnO/CdS/Cu(In,Ga)Se2/Mo solar cell
Authors: Contreras Miguel A. , Gabor Andrew M. , Tennant Andrew L. , Asher Sally , Tuttle John , Noufi Rommel
Published: July 2007

This communication reports an MgF2/ZnO/CdS/Cu(In,Ga)Se2/Mo/glass polycrystalline solar cell with a confirmed total‐area conversion efficiency of 16.4%. the thin‐film Cu(In,Ga)Se2absorber was fabricated by computer‐controlled physical vapor deposition (PVD) from the elemental sources. the resulting absorber has a Gal/In compositional grading that we refer to as a notch. Capacitance‐voltage (C‐V) measurements also reveal a graded doping profile in the region near the electronic p‐n junction. the enhanced device performance is characterized by an open‐circuit voltage (Voc) of 660 mV and a particularly high fill factor (FF) of 78.7%.
Solar photovoltaics in Sri Lanka: A short history
Authors: Gunaratne Lalith
Published: July 2007

With a significant unelectrified rural population, Sri Lanka has followed the evolution of solar photovoltaic (PV) technology in the West very closely since the 1970s as terrestrial applications for photovoltaics were developed. It was not until 1980 that the Sri Lankan government embarked on the promotion of solar photovoltaics for rural domestic use when the Ceylon Electricity Board formed the Energy Unit.

Since then, solar photovoltaics has attracted the private sector, where several companies have been operating at different levels with varying degrees of success‐Vidya Silpa, agents for Arco and now Showa, selling solar photovoltaic systems on a small scale; Power & Sun (now S.P.&L. Co. Ltd) with its solar photovoltaic module assembling facility and a marketing operation; Sunpower Systems, agents for BP Solar Australia, focusing on institutional systems; and BP Solar Australia working on government‐funded projects‐so that private solar photovoltaic promoters have now gained valuable experience in a variety of dissemination methodologies.

In addition, Australian and Sri Lankan government‐funded pilot projects such as the Pansiyagama 1000 home programme and the Uva Infrastructure Project with 74 large‐scale solar photovoltaic systems for rural hospitals and water pumping schemes‐ both administered by the National Housing Development Authority (NHDA) ‐have given all the local promoters further valuable insight into how and how not to promote solar photovoltaics.

The establishment of community‐based solar photovoltaic programmes by non‐governmental organizations, such as the Sarvodaya Shramadana Society and the newly formed Solanka Associates, has developed a novel approach to bridge the gap between this state‐of‐the‐art technology and the remotely located end‐users.

The developments in the Sri Lankan solar photovoltaic scene have attracted the attention of the World Bank. to quote from a paper presented by Loretta Schaeffer, Program Manager of the Bank's Asia Alternative Energy Unit in Washington at the Solar Energy Forum‐SOLTECH'93‐held on 28th April 1993 in Washington, DC: ‘The Bank may get involved in providing PV‐powered household systems throughout the country as there is a strong private sector involvement and use of proven local experience in systems design, development, installation, operation and maintenance’.

Even though 70% of the 3.3 million homes are unelectrified, acceptance of solar photovoltaics as a viable alternative by policy makers is yet to be fully realized in Sri Lanka. the main obstacle has been the relatively high cost of photovoltaics. In spite of this, the private sector companies, certain government agencies (such as the NHDA) and the non‐government organizations view photovoltaics as a technology that could meet the basic needs for electricity of the rural people who, otherwise, would be left in the dark.
Studies of the micro‐ and nanostructure of polycrystalline CdTe and CuInSe2using atomic force and scanning tunneling microscopy
Authors: Moutinho H. R. , Hasoon F. S. , Kazmerski L. L.
Published: July 2007

Atomic force microscopy (AFM) and scanning tunneling microscopy (STM) have been used to study the micro‐ and nanostructure of CdTe and CuInSe2thin films used for photovoltaic cells. Topographic images are comparable with those reported previously using conventional scanning electron microscopy (SEM)—to the limit of spatial resolution of the SEM technique. For higher magnifications, nanoscale structures and features have been observed for the first time with AFM and STM, and these observations have implications for the suitability and preparation of these semiconductors for high‐efficiency solar cell realization.
Accelerated publication 30.2% efficient GaInP/GaAs monolithic two‐terminal tandem concentrator cell
Authors: Friedman D. J. , Kurtz Sarah R. , Bertness K. A. , Kibbler A. E. , Kramer C. , Olson J. M. , King D. L. , Hansen B. R. , Snyder J. K.
Published: July 2007

The Ga0.5In0.5P/GaAs monolithic two‐terminal tandem cell has been adapted for concentrator operation. the adaptation involves changes in the grid design, top‐cell base thickness and top‐cell emitter thickness. the prototype concentrator device has demonstrated an efficiency exceeding 30% in the concentration range of 115‐260 suns, making this the first two‐terminal monolithic cell to exceed 30% efficiency.
Solar cell efficiency tables (version 5)
Authors: Green Martin A. , Emery Keith , Bücher Klaus , King David L.
Published: July 2007

Updated tables showing an extensivé listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and several new entries since July 1994 are briefly described.
New insights gained through pilot production of high‐eficiency silicon solar cells
Authors: Honsberg C. B. , Wenham S. R.
Published: July 2007

Examination of results from the pilot production of buried‐contact solar cells (BCSC) allows several new insights into the effects of the substrate resistivity, the differences between upright and inverted pyramid texturing, the reflection after encapsulation and the doping level at which the emitter begins to dominate the overall recombination. A lower substrate resistivity in conjunction with thicker wafers reduces the effects of a high back surface recombination velocity and allows both higher voltages and efficiencies. In BCSCs with low substrate resistivities, the voltage is not limited by the back but by the emitter diffusion and the dislocation formation at the surface. Contrary to previous reports, best results have been realized with upright pyramids rather than inverted pyramids. In addition, the relative performance of the upright pyramids improves after encapsulation owing to the less than optimal unencapsulated reflection of these surfaces in the regions of the pyramid peaks where oxide layers are too thin to gain benefits as an antireflection layer. Recent results also indicate that the contributions to the dark saturation current from both the heavily phosphorus‐diffused region beneath the metal contact and the more lightly diffused top surface emitter are less than indicated previously. Finally, comparison between experimentally obtained voltages and those predicted through modelling with PC‐1D provides an estimate of the bulk material lifetimes in the pilot line cells.
Optical properties of intrinsic silicon at 300 K
Authors: Green Martin A. , Keevers Mark J.
Published: July 2007

An updated tabulation is presented of the optical properties of intrinsic silicon relevant to solar cell calculations. the absorption coeficient, refractive index and extinction coeficient at 300 K are tabulated over the 0.25‐1.45 μm wavelength range at 0.01 μm intervals.
17% Eficient thin‐film silicon solar cell by liquid‐phase epitaxy
Authors: Blakers A. W. , Weber K. J. , Stuckings M. F. , Armand S. , Matlakowski G. , Carr A. J. , Stocks M. J. , Cuevas A. , Brammer T.
Published: July 2007

Thin‐film silicon solar cells are promising candidates for meeting the requirements of high efficiency combined with low cost. We use liquid‐phase epitaxy to grow thin silicon films on highly doped substrates. A solar cell made on this material has been measured independently to have an efficiency of 17.0%. an important step in obtaining these high cell efficiencies is the removal of most of the heavily doped substrate on which the epitaxial layer is grown.
Estimation of the effects of an intensive solar intervention in the historical centre of jaén (Spain)
Authors: Almonacid G. , Nofuentes G. , Aguilar J. D. , De Casa J. La , Garrido A.
Published: July 2007

This paper is directed at evaluating the theoretical potential of an intensive solar intervention in the historical centre of the city of Jaén (Spain). Using the outputs of a solar intervention proposal comprising biomass, photovoltaics and solar thermal domestic hot water (DHW) over a 50‐building sample (in which those suitable for solar measures have been selected by evaluating each one over a collection of parameters), energy savings, environmental benefits and economic aspects of the envisaged actions are extrapolated over the entire historical centre. A saving of about 70% of conventional source energy annual consumption and a decrease of some 70% and 73% of CO2 and SOx annual releases, respectively, could be reached with respect to the present situation. Besides, an amount of conventionally generated electricity equivalent to the yearly photovoltaic‐generated electricity would require 131500 m3 of water a year, which is a rather significant feature for a dry climate like that of the city. the unitary cost of energy in the new scenario would be 60.7 pta kWh‐1 for photovoltaics, 329.9 pta m‐3 for DHW using solar thermal installations and 4.6 Pta kWh‐1 for biomass heating (1 US$ = 132.7 pta; 1 ECU = 160.9 pta).
Accelerated publication 17.1% efficient Cu(In,Ga)Se2‐based thin‐film solar cell
Authors: Tuttle J. R. , Contreras M. A. , Gillespie T. J. , Ramanathan K. R. , Tennant A. L. , Keane J. , Gabor A. M. , Noufi R.
Published: July 2007

We report a world‐record, total‐area efficiency of 17.1% for a polycrystalline thin‐film Cu(In,Ga)Se2‐based photovoltaic solar cell. the incorporation of Ga to raise the absorber bandgap has been accomplished successfully and in such a manner that an open‐circuit voltage of 654 mV and a fill factor of greater than 77% have been achieved. We describe briefly the deposition process, the device structure, and the device performance characteristics.
Anti‐herpes simplex virus activities ofEugenia caryophyllus(Spreng.) Bullock & S. G. Harrison and essential oil, eugenol
Authors: Tragoolpua Y. , Jatisatienr A.
Published: July 2007

In this study, an extract from the flower buds ofEugenia caryophyllus(Spreng.) Bullock & S. G. Harrison and the essential oil, eugenol, were evaluated for their anti‐herpes simplex virus properties on standard HSV‐1(F), standard HSV‐2(G) and ten HSV isolates. The plaque reduction assay showed that HSV‐1(F), HSV‐2(G), two HSV‐1 isolates (2, 30) and four HSV‐2 isolates (1, 2, 3, 21) were inhibited byE. caryophyllus. Only HSV‐1 isolates 1 and 30 were inhibited by eugenol. Thus, strains or isolates of viruses may affect the range of inhibition. Moreover, particles of HSV standard strains were directly inactivated byE. caryophyllusand eugenol. The total virus yield of HSV standard strains and isolates at 30 h also declined after treatment withE. caryophyllusand eugenol. TheE. caryophyllusextract exerted higher antiviral replication on HSV‐2(G) than on HSV‐1(F). The inhibition of the viral yield of HSV‐1 isolates was higher than standard HSV‐1(F) and standard HSV‐2(G) was also inhibited more than most of the HSV‐2 isolates. The anti‐HSV activity of eugenol against HSV‐1(F) and HSV isolates was stronger than with theE. caryophylluscrude extract. However, the percentage inhibition was more pronounced on HSV‐1(F) than on HSV‐2(G). Moreover, HSV‐1(1) and HSV‐2(1, 32) could not replicate when eugenol was included in the assay. Copyright © 2007 John Wiley & Sons, Ltd.
Simulations of the consequences of tongue surgery on tongue mobility: implications for speech production in post‐surgery conditions
Authors: Buchaillard Stéphanie , Brix Muriel , Perrier Pascal , Payan Yohan
Published: July 2007

Background

We studied the ability of a three‐dimensional (3D) biomechanical model of the oral cavity to predict the consequences of tongue surgery on tongue movements, according to the size and location of the tissue loss and the nature of the flap used by the surgeon.

Method

The core of our model consists of a 3D biomechanical model representing the tongue as a finite element structure with hexahedral elements and hyperelastic properties, in which muscles are represented by specific subsets of elements. This model is inserted in the oral cavity including jaw, palate and pharyngeal walls. Hemiglossectomy and large resection of the mouth floor are simulated by removing the elements corresponding to the tissue losses. Three kinds of reconstruction are modelled, assuming flaps with low, medium or high stiffness.

Results

The consequences of these different surgical treatments during the activation of some of the main tongue muscles are shown. Differences in global 3D tongue shape and in velocity patterns are evaluated and interpreted in terms of their potential impact on speech articulation. These simulations have been shown to be efficient in accounting for some of the clinically observed consequences of tongue surgery.

Conclusion

Further improvements still need to be done before being able to generate patient‐specific models easily and to decrease the computation time significantly. However, this approach should represent a significant improvement in planning tongue surgery systems and should be a very useful means of improving the understanding of muscle behaviour after partial resection. Copyright © 2007 John Wiley & Sons, Ltd.
Bifurcations and chaotic behavior in a simple model of the economic long wave
Authors: Rasmussen Steen , Mosekilde Erik , Sterman John D.
Published: July 2007

This paper presents a formal stability analysis of a simplified Kondratieff wave model. For normal parameter values the model has a single unstable equilibrium point which, combined with nonlinear constraints in the model's table functions, creates a characteristic limit cycle behavior. For other parameter values, the model generates damped oscillations instead of the limit cycle or overwhelms the nonlinear constraints and exhibits sustained exponential growth or total collapse.

By linear stability analysis we first determine the conditions for a Hopf bifurcation, the transition from a stable to an unstable equilibrium. Using global analysis, we outline the phase portrait of a fully developed limit cycle. By the same method we examine the conditions under which the nonlinear functions fail to contain the system so that exponential runaway or collapse occurs. We then develop a DYNAMO program to calculate the Lyapunov exponents of the system during a simulation and discuss how these can be measures of the divergence or convergence of nearby trajectories. Finally, we illustrate how subsequent period doublings and chotic behavior can occur if the model is driven exogennously by a weak sine wave, representing, for instance, the shorterm business cycle.
Aggregation in system dynamics
Authors: Rahn R. Joel
Published: July 2007

Stochastic aspects of systems have generally been ignored in most system dynamics studies except for purposes of sensitivity testing. Yet any model that claims to be more than simply a phenomenological description of a system must treat the underlying stochasticity explicitly in terms of its contribution to the dynamics. Recent work in chemical, biological, and hydrodynamic systems has shown that the aggregation of stochastic effects can lead to novel behavior (self‐organization in dissipative systems).

In this paper, an analogy between models of these physical systems and system dynamics models is developed, in which dynamic models are seen to be an approximation (to lowest order in an expansion in system size) to a stochastic model for the system. The theoretical results derived for the physical system models are evaluated for their application to system dynamics models. A research strategy to elaborate this approach to analyzing a more general class of systems is proposed.
Algorithmic control modules for system dynamics models
Authors: Wolstenholme E. F.
Published: July 2007

This paper describes a framework for policy analysis and design in soft, complex systems based on the transfer to such systems of control modules developed for harder (more easily quantified), simpler systems. The framework is demonstrated by outlining the development of a dynamic allocation algorithm within a system dynamics model of an engineering system and describing its application in a much larger scale management system. The potential use of this algorithm is demonstrated in two other systems, and a generalized form is presented that highlights its isomorphic qualities. It is suggested that this framework, which treats the physical and control structure of a system as a unified whole, can provide a useful contribution to policy analysis.
The dynamics of a fledgling high‐technology growth market: Understanding and managing growth cycles
Authors: Morecroft John D. W.
Published: July 2007

This paper presents a system dynamics model of the fledgling market for automated storage and retrieval AS/RS systems based on a case study of a leading firm in the industry. The model examines how marketing effort, capacity expansion, and industry reputation interact to produce growth cycles of eight to nine years' duration in demand and capacity for AS/RS systems. A series of partial model simulations is used to explain how the growth cycles are generated by the feedback structure and behavioral assumptions of the model. A policy experiment is presented to show how a mature firm in the industry can influence the growth cycles to improve its financial performance. Finally, the feedback structure governing market diffusion and capacity expansion is generalized to other high‐technology products and markets.