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Kinematic Design of a Translational Parallel Manipulator with Fine Adjustment of Platform Orientation  [PDF]
Masataka Tanabe,Yukio Takeda
Advances in Mechanical Engineering , 2010, DOI: 10.1155/2010/485358
Abstract: We present a kinematic design of a translational parallel manipulator with fine adjustment capability of platform orientation. In order to clarify possible kinematic structures for it, structural synthesis of fully decoupled mechanism and partially decoupled mechanism both with six degrees of freedom (dof) was carried out based on the synthesis results of translational and rotational parallel mechanisms with three dof. All possible kinematic structures were obtained. Of these, one partially decoupled mechanism was selected and a kinematic design of a prototype manipulator was done. Its characteristics in terms of workspace, singularity, orientation adjustment capability, and coupling characteristics between translational and rotational displacement were discussed with experimental results regarding fine adjustment capability of platform orientation. 1. Introduction A parallel manipulator that has three degrees of freedom (dof) and outputs translational motion without changing its orientation is called a “translational parallel manipulator.” A translational parallel manipulator has potential for use in assembly, machining, and coordinate measurements. The manipulator is composed of a base, platform, and multiple connecting chains arranged in parallel between the base and platform. Many researchers in recent years have shown interest in translational parallel manipulators and mechanisms. The kinematic conditions for the connecting chain to obtain translational motion of the platform have been investigated [1, 2]. Various kinematic structures for translational parallel manipulators have also been investigated [3, 4]. Further, optimization taking into consideration the manipulator’s workspace has been done [5–7]. Translational parallel mechanisms have been applied to medical robots [8] and micromanipulators [9]. The errors in the output pose of a manipulator caused by dimensional errors, such as these in links, can be classified into two groups. The first group contains errors that can be compensated for by calibration or full closed-loop control. Such errors are called “compensatable errors” [10, 11]. The tolerance requirements with respect to these compensatable errors depend on calibration or the performance of the controller, and these are not usually severe. The second group contains errors that cannot be compensated for by any means, either during or prior to manipulation. Such errors are called “uncompensatable errors” [10, 11]. They depend on kinematic structures and parameters and tolerances. In designing and controlling a lower-dof parallel
The cancer translational research informatics platform
Patrick McConnell, Rajesh C Dash, Ram Chilukuri, Ricardo Pietrobon, Kimberly Johnson, Robert Annechiarico, A Jamie Cuticchia
BMC Medical Informatics and Decision Making , 2008, DOI: 10.1186/1472-6947-8-60
Abstract: caTRIP has been developed as an N-tier architecture, with three primary tiers: domain services, the distributed query engine, and the graphical user interface, primarily making use of the caGrid infrastructure to ensure compatibility with other tools currently developed by caBIG. The application interface was designed so that users can construct queries using either the Simple Interface via drop-down menus or the Advanced Interface for more sophisticated searching strategies to using drag-and-drop. Furthermore, the application addresses the security concerns of authentication, authorization, and delegation, as well as an automated honest broker service for deidentifying data.Currently being deployed at Duke University and a few other centers, we expect that caTRIP will make a significant contribution to further the development of translational research through the facilitation of its data exchange and storage processes.In order to have an impact in society, discoveries in cancer research need to be translated into knowledge that can be directly applied to treatment and prevention. These discoveries usually start within the basic sciences, from experiments developed at the molecular level, slowly progressing to clinical research. Although this translational process is at the very basis of our ability to generate new biomedical knowledge, to date few tools have been developed to successfully link the basic and clinical science fields in a way that researchers from both arenas can easily make connections. More specifically, cancer research would benefit from the development of applications that can aggregate clinical and molecular data in a repository that is user-friendly, easily accessible, as well as compliant with regulatory requirements of privacy and security.In alignment with the requirements outlined above, the Duke Comprehensive Cancer Center (DCCC), in collaboration with SemanticBits LLC, has developed the Cancer Translational Research Informatics Platform (c
Frequency Optimization Objective during System Prototyping on Multi-FPGA Platform  [PDF]
Mariem Turki,Zied Marrakchi,Habib Mehrez,Mohamed Abid
International Journal of Reconfigurable Computing , 2013, DOI: 10.1155/2013/853510
Abstract: Multi-FPGA hardware prototyping is becoming increasingly important in the system on chip design cycle. However, after partitioning the design on the multi-FPGA platform, the number of inter-FPGA signals is greater than the number of physical connections available on the prototyping board. Therefore, these signals should be time-multiplexed which lowers the system frequency. The way in which the design is partitioned affects the number of inter-FPGA signals. In this work, we propose a set of constraints to be taken into account during the partitioning task. Then, the resulting inter-FPGA signals are routed with an iterative routing algorithm in order to obtain the best multiplexing ratio. Indeed, signals are grouped and then routed using the intra-FPGA routing algorithm: Pathfinder. This algorithm is adapted to deal with the inter-FPGA routing problem. Many scenarios are proposed to obtain the most optimized results in terms of prototyping system frequency. Using this technique, the system frequency is improved by an average of 12.8% compared to constructive routing algorithm. 1. Introduction With the ever increasing complexity of system on chip circuits, the software and hardware developers can no longer wait for the fabrication phase to test their designs [1]. Currently, it is estimated that 60 to 80 percent of an ASIC design is spent in performing verification [2]. FPGA-based prototyping is an important step in the creation of the final product and it is the key to the success of marketing in time. The key advantage of FPGA-based prototyping is the ability to run at high speed (sometimes at almost real-time speed) a cycle-accurate, bit-accurate model of the SoC [3]. The availability of automatic FPGA mapping tools has streamlined the design conversion process, making the path from ASIC design to FPGA implementation more straightforward. When the logic capacity of a single FPGA is less than the size of the design under test, a multi-FPGA platform is used to map the entire design. Because the silicon area overhead of FPGA versus ASIC technology has been measured to be about 40x [4], FPGA programming technology requires that an ASIC logic design be partitioned across multiple FPGA devices to achieve the necessary device logic capacity. The number of FPGAs depends on the size of the prototyping system, ranging from a few [5] up to 60 FPGAs [6]. In order to map the design into a multi-FPGA board, a partitioning tool decomposes the design into pieces that will fit within the logic resources of individual FPGA devices. Partitioning is often performed to
Integration of a Balanced Virtual Manikin in a Virtual Reality Platform aimed at Virtual Prototyping  [PDF]
Antoine Rennuit,Alain Micaelli,Xavier Merlhiot,Claude Andriot,Fran?ois Guillaume,Nicolas Chevassus,Damien Chablat,Patrick Chedmail
Computer Science , 2007,
Abstract: The work presented here is aimed at introducing a virtual human controller in a virtual prototyping framework. After a brief introduction describing the problem solved in the paper, we describe the interest as for digital humans in the context of concurrent engineering. This leads us to draw a control architecture enabling to drive virtual humans in a real-time immersed way, and to interact with the product, through motion capture. Unfortunately, we show this control scheme can lead to unfeasible movements because of the lack of balance control. Introducing such a controller is a problem that was never addressed in the context of real-time. We propose an implementation of a balance controller, that we insert into the previously described control scheme. Next section is dedicated to show the results we obtained. Finally, we propose a virtual reality platform into which the digital character controller is integrated.
A Prototyping Virtual Socket System-On-Platform Architecture with a Novel ACQPPS Motion Estimator for H.264 Video Encoding Applications  [cached]
Yifeng Qiu,Wael Badawy
EURASIP Journal on Embedded Systems , 2009, DOI: 10.1155/2009/105979
Abstract: H.264 delivers the streaming video in high quality for various applications. The coding tools involved in H.264, however, make its video codec implementation very complicated, raising the need for algorithm optimization, and hardware acceleration. In this paper, a novel adaptive crossed quarter polar pattern search (ACQPPS) algorithm is proposed to realize an enhanced inter prediction for H.264. Moreover, an efficient prototyping system-on-platform architecture is also presented, which can be utilized for a realization of H.264 baseline profile encoder with the support of integrated ACQPPS motion estimator and related video IP accelerators. The implementation results show that ACQPPS motion estimator can achieve very high estimated image quality comparable to that from the full search method, in terms of peak signal-to-noise ratio (PSNR), while keeping the complexity at an extremely low level. With the integrated IP accelerators and optimized techniques, the proposed system-on-platform architecture sufficiently supports the H.264 real-time encoding with the low cost.
A Prototyping Virtual Socket System-On-Platform Architecture with a Novel ACQPPS Motion Estimator for H.264 Video Encoding Applications  [cached]
Qiu Yifeng,Badawy Wael
EURASIP Journal on Embedded Systems , 2009,
Abstract: H.264 delivers the streaming video in high quality for various applications. The coding tools involved in H.264, however, make its video codec implementation very complicated, raising the need for algorithm optimization, and hardware acceleration. In this paper, a novel adaptive crossed quarter polar pattern search (ACQPPS) algorithm is proposed to realize an enhanced inter prediction for H.264. Moreover, an efficient prototyping system-on-platform architecture is also presented, which can be utilized for a realization of H.264 baseline profile encoder with the support of integrated ACQPPS motion estimator and related video IP accelerators. The implementation results show that ACQPPS motion estimator can achieve very high estimated image quality comparable to that from the full search method, in terms of peak signal-to-noise ratio (PSNR), while keeping the complexity at an extremely low level. With the integrated IP accelerators and optimized techniques, the proposed system-on-platform architecture sufficiently supports the H.264 real-time encoding with the low cost.
Towards dynamical network biomarkers in neuromodulation of episodic migraine  [PDF]
Markus A. Dahlem,Sebastian Rode,Arne May,Naoya Fujiwara,Yoshito Hirata,Kazuyuki Aihara,Jürgen Kurths
Quantitative Biology , 2013, DOI: 10.2478/s13380-013-0127-0
Abstract: Computational methods have complemented experimental and clinical neursciences and led to improvements in our understanding of the nervous systems in health and disease. In parallel, neuromodulation in form of electric and magnetic stimulation is gaining increasing acceptance in chronic and intractable diseases. In this paper, we firstly explore the relevant state of the art in fusion of both developments towards translational computational neuroscience. Then, we propose a strategy to employ the new theoretical concept of dynamical network biomarkers (DNB) in episodic manifestations of chronic disorders. In particular, as a first example, we introduce the use of computational models in migraine and illustrate on the basis of this example the potential of DNB as early-warning signals for neuromodulation in episodic migraine.
Translational Neurodegeneration, a platform to share knowledge and experience in translational study of neurodegenerative diseases
Shengdi Chen, Jialin C Zheng
Translational Neurodegeneration , 2012, DOI: 10.1186/2047-9158-1-1
Abstract: Indeed, the prevalence of neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD), has increased significantly as global populations age. Specifically, the number of cases of dementia in the developed world is projected to rise from 13.5 million in 2000 to 21.2 million in 2025, and to 36.7 million in 2050[1]. Currently, the number of deaths caused by AD is only next to the number of deaths caused by stroke. As the prevalence of AD grows, so does the cost to a nation. For PD, the second most common neurodegenerative disease after AD, more than 4 million people suffer from this devastating disease worldwide and that will double in the next 25 years [2]. To date, PD is still an incurable progressive neurological disorder that seriously impairs the quality of life.The discovery and application of levodopa (L-dopa) is one of the best examples of translational research for neurodegenerative diseases. In 1910s, L-dopa was first isolated from seedlings of Vicia faba; and in 1938, L-dopa decarboxylase was discovered, which can produce dopamine (DA) from L-dopa. In 1959, DA was found enriched in the basal ganglia; and in 1960, a severe striatal DA deficit was demonstrated in PD patients. These major discoveries and a deepening understanding of the neurochemistry of DA and the neuropathology of PD led to the concept of "DA replacement" with L-dopa. In 1961, L-dopa was tried in PD patients by i.v. treatment. In 1967, oral administration of L-dopa was reported to produce dramatic improvements in PD patients with increasing amounts over long periods [3]. However, the main side effects of increasing L-dopa administration, i.e., dyskinesias and motor fluctuations, became apparent. This clinical finding confused doctors and patients, and a solution was needed. In 1970s, the key cause was found. L-dopa decarboxylase degraded L-dopa to DA in peripheral blood, which can not across the blood-brain barrier. These findings led to the first L-dopa combi
Fools gold? Developer dilemmas in a closed mobile application market platform  [PDF]
Joni Salminen,Jose Teixeira
Computer Science , 2014, DOI: 10.1007/978-3-642-39808-7_11
Abstract: In this paper, we outline some potential conflicts that platform owners and software developers face in mobile application markets. Our arguments are based on comments captured in specialized online discussion forums, in which developers gather to share knowledge and experiences. The key findings indicate conflicts of interests, including 1) intra-platform competition, 2) discriminative promotion, 3) entry prevention, 4) restricted monetization, 5) restricted knowledge sharing, 6) substitution, and 7) strategic technology selection. Opportunistic platform owners may use their power to discriminate between third-part software developers. However, there are also potential strategic solutions that developers can apply; for example diversification (multi-homing), syndication and brand building.
Neuromodulation: present and emerging methods  [PDF]
Song Luan,Ian Williams,Konstantin Nikolic,Timothy G. Constandinou
Frontiers in Neuroengineering , 2014, DOI: 10.3389/fneng.2014.00027
Abstract: Neuromodulation has wide ranging potential applications in replacing impaired neural function (prosthetics), as a novel form of medical treatment (therapy), and as a tool for investigating neurons and neural function (research). Voltage and current controlled electrical neural stimulation (ENS) are methods that have already been widely applied in both neuroscience and clinical practice for neuroprosthetics. However, there are numerous alternative methods of stimulating or inhibiting neurons. This paper reviews the state-of-the-art in ENS as well as alternative neuromodulation techniques—presenting the operational concepts, technical implementation and limitations—in order to inform system design choices.
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