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Algorithms and architectures for decimal transcendental function computationChen, Dongdong 27 January 2011 (has links)
Nowadays, there are many commercial demands for decimal floating-point (DFP) arithmetic operations such as financial analysis, tax calculation, currency conversion, Internet based applications, and e-commerce. This trend gives rise to further development on DFP arithmetic units which can perform accurate computations with exact decimal operands. Due to the significance of DFP arithmetic, the IEEE 754-2008 standard for floating-point arithmetic includes it in its specifications. The basic decimal arithmetic unit, such as decimal adder, subtracter, multiplier, divider or square-root unit, as a main part of a decimal microprocessor, is attracting more and more researchers' attentions. Recently, the decimal-encoded formats and DFP arithmetic units have been implemented in IBM's system z900, POWER6, and z10 microprocessors.<p>
Increasing chip densities and transistor count provide more room for designers to add more essential functions on application domains into upcoming microprocessors. Decimal transcendental functions, such as DFP logarithm, antilogarithm, exponential, reciprocal and trigonometric, etc, as useful arithmetic operations in many areas of science and engineering, has been specified as the recommended arithmetic in the IEEE 754-2008 standard. Thus, virtually all the computing systems that are compliant with the IEEE 754-2008 standard could include a DFP mathematical library providing transcendental function computation. Based on the development of basic decimal arithmetic units, more complex DFP transcendental arithmetic will be the next building blocks in microprocessors.<p>
In this dissertation, we researched and developed several new decimal algorithms and architectures for the DFP transcendental function computation. These designs are composed of several different methods: 1) the decimal transcendental function computation based on the table-based first-order polynomial approximation method; 2) DFP logarithmic and antilogarithmic converters based on the decimal digit-recurrence algorithm with selection by rounding; 3) a decimal reciprocal unit using the efficient table look-up based on Newton-Raphson iterations; and 4) a first radix-100 division unit based on the non-restoring algorithm with pre-scaling method. Most decimal algorithms and architectures for the DFP transcendental function computation developed in this dissertation have been the first attempt to analyze and implement the DFP transcendental arithmetic in order to achieve faithful results of DFP operands, specified in IEEE 754-2008.<p>
To help researchers evaluate the hardware performance of DFP transcendental arithmetic units, the proposed architectures based on the different methods are modeled, verified and synthesized using FPGAs or with CMOS standard cells libraries in ASIC. Some of implementation results are compared with those of the binary radix-16 logarithmic and exponential converters; recent developed high performance decimal CORDIC based architecture; and Intel's DFP transcendental function computation software library. The comparison results show that the proposed architectures have significant speed-up in contrast to the above designs in terms of the latency. The algorithms and architectures developed in this dissertation provide a useful starting point for future hardware-oriented DFP transcendental function computation researches.
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Temperature robust programmable subthreshold circuits through a balanced force approachDegnan, Brian Paul 18 January 2013 (has links)
The subthreshold region of operation has simple physics which allows for a balanced-force approach to behavioral modeling that has shown to be robust to temperature, and a model that encapsulates MOSFET behavior across all operational regions has been developed. The subthreshold region of operation also allows for injection of charge onto floating nodes that allows for persistent storage that can be used in a variety of applications. The combination of charge storage and device modeling has allowed for the development of programmable circuits for digital applications.
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Floating Bodies in the Absence of GravityKemp, Todd Murray January 2011 (has links)
The study of infinitely long cylinders of constant cross-section floating in an infinite fluid bath in zero-gravity environments has primarily been focused on bodies whose cross-sections are strictly convex and sufficiently smooth. In this thesis, our efforts are concentrated on the consideration of bodies that are only convex and piecewise smooth. These types of bodies are seldom considered in current literature. We have worked with a series expansion of the energy function in order to determine when configurations of a given body will be in equilibrium, stable or otherwise. We have proven that any convex body with a straight side cannot float in a stable equilibrium with the fluid interface intersecting the interior of the straight side in a single point. This fact is then used to prove necessary and sufficient conditions for stable equilibrium of polygons, bodies whose cross-sections are comprised of only straight sides. We illustrate these conditions with several examples.
In the latter portion of the thesis, we turn our attention to bodies in three dimensions. While past research has again been focused on strictly convex bodies, we began to consider bodies that do not meet these requirements by examining bodies of revolution. A condition for stability with respect to vertical variations of bodies of revolution is derived. We conclude with several examples of bodies of revolution, some of which interestingly relate back to an analogous two-dimensional shape.
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Adaptive Analog VLSI Signal Processing and Neural NetworksDugger, Jeffery Don 26 November 2003 (has links)
Research presented in this thesis provides
a substantial leap from the study of interesting
device physics to fully adaptive analog networks
and lays a solid foundation for future development
of large-scale, compact, low-power adaptive parallel
analog computation systems.
The investigation described here started with
observation of this potential learning capability
and led to the first derivation and characterization of
the floating-gate pFET correlation learning rule.
Starting with two synapses sharing the same error signal,
we progressed from phase correlation experiments
through correlation experiments involving harmonically related sinusoids,
culminating in learning the Fourier series coefficients
of a square wave cite{kn:Dugger2000}.
Extending these earlier two-input node experiments to the general case
of correlated inputs required dealing with
weight decay naturally exhibited by the learning rule.
We introduced a source-follower floating-gate synapse
as an improvement over our earlier source-degenerated floating-gate synapse
in terms of relative weight decay cite{kn:Dugger2004}.
A larger network of source-follower floating-gate synapses was fabricated
and an FPGA-controlled testboard was designed and built.
This more sophisticated system provides an excellent
framework for exploring applications to multi-input, multi-node
adaptive filtering applications.
Adaptive channel equalization provided
a practical test-case illustrating the use
of these adaptive systems in solving real-world problems.
The same system could easily be applied to noise and echo cancellation
in communication systems and system identification tasks in
optimal control problems.
We envision the commercialization of these adaptive analog VLSI
systems as practical products within a couple of years.
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Dynamic analysis on an offshore floating raft for oyster aquacultureLee, Kuan-Ying 02 July 2010 (has links)
The purpose of this study is to investigate the hydrodynamic properties of an oyster floating raft system under environmental loadings. The floating raft system is an important facility for raising oyster in the near shore area of Tainan, Taiwan. The reasons for this kind of oyster culture being main income source for local fish farmers are as the following features: (1) low cost for the farming system, (2) easily to be installed in the field, and (3) easily to be harvested. Due to the raft structure could not withstand the impact of heavy storms; most of the oyster rafts are towed into harbor to avoid damage before the onset of typhoon. Since some unexpected violent sea states may occur and severely affect the integrity of raft system, the investigation of the hydrodynamic properties of a floating raft system is essential for oyster culture in the open sea. This study includes two parts: numerical simulation and physical modeling. In numerical simulation, a lumped mass method with a Morison type of relative motion equation are adopted to calculate the drag and inertial forces on raft components and then are equally divided to the associated nodes to form a system of motion equations based on Newton¡¦s second law. Through the fourth-order Runge-Kutta method, the dynamic performance of the oyster raft system can be obtained. To verify the numerical model, a physical model was carried out in a wave tank (35x1x1.2 m), and the results of dynamic performance of numerical model show good agreement with measurements.
A case study of an in situ oyster farming system located near-shore of Tainan region is analyzed by the developed numerical model to investigate the maximum mooring tension, the optimal gap between rafts, and the required length of mooring line. These specifications are crucial to the shell fish farmers for their floating raft system to be survived in the strong currents and waves. The results showed that the optimum configuration for a raft system generated the lowest mooring tension is as the follows: the space between oyster rafts is about a length of oyster raft; the length of mooring line is three times of the water depth, which is consistent with the present practice of shell fish farmers adopting 3~4 times of water depth; the appropriate embedment anchor weight is 70 kg but the anchorage should be the type used by the farmers in Penghu county. Finally, this work intends to offer a guideline for the installation of oyster raft systems in the field, and anticipate minimizing the damage during the unexpected heavy sea states.
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Simulation and Measurement of ESD Test for Electronic DevicesChiu, Kuan-Ming 21 June 2004 (has links)
The trends of present design in electronic systems are towards high speed, small size, and lower voltage levels. Due to these trends, the influence of ESD becomes a more serious problem for an EMC designer. How to precisely evaluate the effect of ESD by measurement and simulation, and try to solve these questions quickly is the most important topic at present.
In this thesis we introduce several measurement approaches to ESD. We try to find the equivalent circuit model of the ESD gun operated in our lab, and construct the simulation model by Agilent ADS software. Good agreement between simulation and measurement demonstrates the correctness of the model for this ESD gun. By combining the simulation model of ESD gun with equivalent circuit of DUT extracted by Ansoft Q3D software, it is found this method can evaluate the ESD phenomena of DUT fast and precisely. In addition, with this method some phenomena restricted by measurement can be studied. Finally two real products including a PDA (floating system) and the mainboard in the desktop computer system (grounding system) are discussed in detail.
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Investigation of ESD Protection Devices in High-speed Digital SystemJan, Yi-Lun 03 July 2005 (has links)
In the trends of high clock rate, lower voltage, small volume, and portable requirement for present electric products, the noise immunity of high speed digital circuit becomes a critical factor for system designer. ESD problem becomes more and more important for electric products because of the triboelectricity caused by human body and synthetic material. It¡¦s an important issue for designer to understand the ESD phenomena in grounding and floating system accurately.
In this thesis, a reliable setup for the ESD measurement is proposed both in grounding and floating systems. ESD behavior and protection devices are studied in detail and a corresponding SPICE model is built up for simulation validation.
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The Analysis of Emergency Department Utilization under Implementing Different Point-values of FeesLian, Shoou-Yang 28 April 2006 (has links)
Abstract
Hospital global budget payment of national health insurance in Taiwan starts from July 1, 2002. The payment of emergency department has fixed point-value from July 1 , 2002 to December 31,2003 ( one point of hospital global budget payment equals one NT dollar) .
But the payment of emergency department becomes floating point-value, shared with out patient department from January 1,2004. Hospital global budget payment of national health insurance in Taiwan suppressed excessive medical supply through the mechanism of floating point-value. The emergency department of hospital in Taiwan can¡¦t refused patient¡¦s visiting by the regulation of law.
We collect the figure of people¡¦s medical utility in emergency department of one regional hospital with 653 beds in Kaohsiung city from July 1 , 2002 to December 31,2003.( one point of hospital global budget payment equals one NT dollar)then the same data also collected from January 1,2004.to July 31,2005.( floating point-value),analyzed by T test.
The research result indicates that : the numbers of patient¡¦s transfer to emergency department increased (p value: ¡Õ¡Õ0.05), the numbers of triage1,2 at emergency department increased (p value : ¡Õ¡Õ0.05), the numbers of emergency visiting each month increased (p value:0.036), the growth of admission don¡¦t have statistic significance (p value:0.509).
Key word: global budget payment¡Bfloating point-value¡Btransfer¡Btriage
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A novel Poly-Si TFT process method for overcoming Self-heating effect and Floating body effectWu, Chu-Lun 31 July 2006 (has links)
In this thesis, we present a new Poly - Si TFT process method to overcome Self - heating effect and Floating body effect. The main drawback of a conventional Poly - Si TFT is the existence of self - heating effect and floating body effect. The self - heating effect leads to drain current reduced and the floating body effect leads to premature device breakdown and kink effects. Here, we utilize all kinds of different isolation technologies to form non - continuing buried layer. Between the non - continuing buried layer there are pass ways, which contact the active region and the substrate directly. Because of conventional LOCOS isolation technology has longer bird¡¦s beak, the familiar method of SILO and PBL isolation technologies are used to reduce bird¡¦s beak. Also, we use STI isolation technology to build up non - continuing buried layer, which can control the width of pass way more easily. It is proved from
the measurement that the pass way can slow down the self - heating effect and the floating body effect successfully.
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Experimental Study on floating Platform for Cage Aquaculture¡ÐWave Energy Transformation AnalysisLi, Sheng-tai 30 August 2006 (has links)
This research focuses not only on the interaction between the floating platform for cage aquaculture and the waves but also on the incident wave¡¬s energy transformation. The floating platform was simulated with a 1:30 physical scale model in the hydrodynamic laboratory. A total four wave gages and one load cell were used in this study: two wave gages installed in the upstream of the platform, one gage in the net cage and one gage in the downstream side of the platform; while one load cell measuring the mooring line tension at the anchor. All of the measurements were recorded in the data acquisition system for further analyzing reflected waves, transmitted waves, the wave height in the net cage, and the correspondent mooring line tensions. Furthermore, the movement of the platform and volume deformation of the fish net are recorded by the video camera, and then analyzed by the image processing method. First, the true color images were transferred into grayscale images, and then passed through mean filter, noise filter and median filter step by step. Finally, a weighted-algorithm was used to calculate the coordinates of the desired point form the resulted image matrix. Thus, the motion of the floating platform and the volume deformation of the fish net can be obtained by analyzing the variation of these points captured through the image processing procedure.
For the ability of resistance to wave attack for a floating platform, it often estimated by inspecting the reflection and transmission coefficients of the platform. Besides the function of wave resistance ability, the stability of the floating platform, maximum tension in the mooring lines and the net volume deformation coefficient are also important factors for optimum design of a cage platform.
According to the results of this research, we conclude some important facts as below: (1) For short-period waves, the net mesh size and twine diameter have influenced the magnitude of reflected waves and the motion of platform; and it makes little difference in the transmission coefficients, wave height ratios inside of net cage, and the maximum tension force in the mooring cable. (2)With the respect of transmitted wave coefficients: the wave transmission phenomena are not obvious for short-period waves, but these phenomena will gradually increase when the incident wave periods are getting longer. (3)Under the pure wave test condition, the net volume deformation coefficients are about 1% only, which means that the deformation of the fish net does not change at all, and it may be due to the overweight of the bottom frame. (4) Tension-leg type mooring system seems able to provide better stability of the platform than catenary type mooring system.
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