An extensible manufacturing resource model for process integration

Driven by industrial needs and enabled by process technology and information technology, enterprise integration is rapidly shifting from information integration to process integration to improve overall performance of enterprises. Traditional resource models are established based on the needs of individual applications. They cannot effectively serve process integration which needs resources to be represented in a unified, comprehensive and flexible way to meet the needs of various applications for different business processes. This paper looks into this issue and presents a configurable and extensible resource model which can be rapidly reconfigured and extended to serve for different applications. To achieve generality, the presented resource model is established from macro level and micro level. A semantic representation method is developed to improve the flexibility and extensibility of the model

Chabauty--Kim and the Section Conjecture for locally geometric sections

Let $X$ be a smooth projective curve of genus $\geq2$ over a number field. A natural variant of Grothendieck's Section Conjecture postulates that every section of the fundamental exact sequence for $X$ which everywhere locally comes from a point of $X$ in fact globally comes from a point of $X$. We show that $X/\mathbb{Q}$ satisfies this version of the Section Conjecture if it satisfies Kim's Conjecture for almost all choices of auxiliary prime $p$, and give the appropriate generalisation to $S$-integral points on hyperbolic curves. This gives a new "computational" strategy for proving instances of this variant of the Section Conjecture, which we carry out for the thrice-punctured line over $\mathbb{Z}[1/2]$

Performance measurements at varying irradiance spectrum, intensity and module temperature of amorphous silicon solar cells

This paper demonstrates photovoltaic (PV) device performance measurements for energy rating and energy yield calculation derived indoors with an LED-based solar simulator prototype under varying irradiance (G), temperature (T) and spectrum (E), opening the possibility for much faster and more accurate energy yield prediction than previously possible from measurements acquired either indoors or outdoors, with the additional inclusion of spectral influences. The main aspects of the LED-based solar simulator used are described briefly and the measurement method with its requirements is explained in detail. Also presented are the first performance measurements made with an amorphous silicon solar cell; measuring the spectral effects reported in outdoor measurements for the first time in the laboratory. Results show a good agreement with previously reported spectral effects from outdoor measurements and underline the importance to consider all three environmental vectors (irradiance, spectrum and device temperature) for energy yield focused measurements

An LED-based photovoltaic measurement system with variable spectrum and flash speed

Outdoor environmental variability leads to the need of artificial illumination systems for PV module characterisation. The two main solar simulator types in use for this purpose, steady state and flash simulators, each have advantages and disadvantages regarding practicality of use and breadth of applicability. To combine the advantages of both types and eliminate the disadvantages, an LED-based solar simulator has been developed, capable of producing light in variable flash speeds and pulse shapes or as a continuous light for long-term measurements. The system features full control of all light sources allowing variable intensity and spectral distribution during measurements. The paper gives a technical description of the measurement system. The results of the initial qualification tests and initial measurements are included

Advantages in using LEDS as the main light source in solar simulators for measuring PV device characteristics

Advances in photovoltaic technology resulted in increased complexity of device calibration, largely being affected by deviations of test spectrum from natural spectra. While the output spectrum of some solar simulators is adjustable, generally only light intensity and module temperature can be varied. This is due to the light sources used in current simulators. LEDs offer an additional degree of freedom, when using an appropriate combination of wavelengths. This paper presents the advantages of this lighting technology for solar simulation and backs these up through results of the prototype unit developed at the Centre for Renewable Energy Systems Technology. The ability to keep LEDs stable for a long time and dim them with minimal changes in the spectrum allows generation of a spectrum closely matched to AM1.5G standard test spectrum or indeed even realistic variations of the outdoor spectrum. LEDs can be controlled very fast within microseconds or operated continuously, combining a steady state and a flash solar simulator with additional functions such as variable flash frequencies and flash shape. Combined with the life expectancy exceeding 50.000h, LEDs are a strong candidate for solar simulator light sources introducing a significant improvement in calibration lifetime as well as significantly reduced running cost. The usage of LEDs can enhance today’s characteristic measurement functions and even opens possibilities to fully characterise solar cells indoors within a much shorter time than is possible today, over a range of conditions previously only available through outdoor characterisation

Towards an accurate and automated characterisation of multi-junction solar cells

A theoretical approach of automated characterisation of single as well as multi-junction solar cells has been developed. The method will be implemented in CREST’s measurement system. It delivers not only I-V characteristics at reference spectrum but also absolute spectral response of the test cell. Thus it opens the way for inline spectral response measurements. The method requires nothing more than a multisource solar simulator, some basic information about the test cell and a calibrated reference cell. Single- and multi-junction measurement procedures are briefly reviewed; the automatic measurement approach is explained and underlined with real and simulation results