Lighting,font style,and polarity on visual performance and visual fatigue with electronic paper displays

Visual performance and visual fatigue of electronic paper displays (electrophoretic display and cholesteric liquid crystal display) under ambient illuminances and light sources were studied and compared with paper. Forty-eight participants participated in a character-search task in the experiment. The results showed that search speed depends on the illuminance but not light source. Search speed increased as illumination increased from 300 lx (45.6 sec), 700 lx (44.18 sec) to 1500 lx (43.24 sec). The effect of medium display and polarity on accuracy was also significant. Accuracy was greater for electrophoretic display and positive polarity. However, the effect of illuminance and light source on visual fatigue was not statistically significant. Based on the results of this study, it seems that E-paper displays may need greater illumination (700 lx or higher).     

Tuning and hybrid parallelization of a genetic-based multi-point statistics simulation code

One of the main difficulties using multi-point statistical (MPS) simulation based on annealing techniques or genetic algorithms concerns the excessive amount of time and memory that must be spent in order to achieve convergence. In this work we propose code optimizations and parallelization schemes over a genetic-based MPS code with the aim of speeding up the execution time. The code optimizations involve the reduction of cache misses in the array accesses, avoid branching instructions and increase the locality of the accessed data. The hybrid parallelization scheme involves a fine-grain parallelization of loops using a shared-memory programming model (OpenMP) and a coarse-grain distribution of load among several computational nodes using a distributed-memory programming model (MPI). Convergence, execution time and speed-up results are presented using 2D training images of sizes 100 × 100 × 1 and 1000 × 1000 × 1 on a distributed-shared memory supercomputing facility.     

Intercross scanning control with double driver for micro-LED display

This paper proposes a control chip for micro-light emitting diode (μLED) applied on real-time display system. The μLED control system has the video transmitter and the LED display matrix. The transmitter includes interface control, memory management, image format conversion. For LED display unit, we present the intercross scanning, memory management, PWM output controller, gamma correction for LED brightness control. TheμLED display is controlled by the intercross drivers to reduce the flicker and promote the sweeping speed with two FPGA controllers, where two parallel SPI data is adopted. The micro LED components are mounted on a PCB with mass-transfer techniques successfully. The FPGA controller can drive about 10 k light-emitting diodes with 12-bit colors for displaying system with PWM method. The passive-matrix micro LED (PMLED) driving can achieve 384 refresh rates with 50 MHz clocking frequency. The experiments result low flicker achieved, which the SVM index is only 1.5 with a photometer measurement.     

Performance assessment and tuning for exchange of clinical documents cross healthcare enterprises

BackgroundTo integrate electronic health records (EHRs) from diverse document sources across healthcare providers, facilities, or medical institutions, the IHE XDS.b profile can be considered as one of the solutions. In this research, we have developed an EHR/OpenXDS system which adopted the OpenXDS, an open source software that complied with the IHE XDS.b profile, and which achieved the EHR interoperability.ObjectiveWe conducted performance testing to investigate the performance and limitations of this EHR/OpenXDS system.MethodologyThe performance testing was conducted for three use cases, EHR submission, query, and retrieval, based on the IHE XDS.b profile for EHR sharing. In addition, we also monitored the depletion of hardware resources (including the CPU usage, memory usage, and network usage) during the test cases execution to detect more details of the EHR/OpenXDS system's limitations.ResultsIn this EHR/OpenXDS system, the maximum affordable workload of the EHR submissions were 400 EHR submissions per hour, the DSA CPU usage was 20%, memory usage was 1380 MB, the network usages were 0.286 KB input and 7.58 KB output per minute; the DPA CPU usage was 1%, memory usage was 1770 MB, the network usages were 7.75 KB input and 1.54 KB output per minute; the DGA CPU usage was 24%, memory usage was 2130 MB, the network usages were 1.3 KB input and 0.174 KB output per minute. The maximum affordable workload of the EHR queries were 600 EHR queries per hour, the DCA CPU usage was 66%, the memory usage was 1660 MB, the network usages were 0.230 KB input and 0.251 KB output per minute; the DGA CPU usage was 1%, the memory usage was 1890 MB, the network usages were 0.273 KB input and 0.22 KB output per minute. The maximum affordable workload of the EHR retrievals were 2000 EHR retrievals, the DCA CPU usage was 79%, the memory usage was 1730 MB, the network usages were 19.55 KB input and 1.12 KB output per minute; the DPA CPU usage was 3.75%, the memory usage was 2310 MB, and the network usages were 0.956 KB input and 19.57 KB output per minute.Discussion and conclusionFrom the research results, we suggest that future implementers who deployed the EHR/OpenXDS system should consider the following aspects. First, to ensure how many service volumes would be provided in the environment and then to adjust the hardware resources. Second, the IHE XDS.b profile is adopted by the SOAP (Simple Object Access Protocol) web service, it might then move onto the Restful (representational state transfer) web service which is more efficient than the SOAP web service. Third, the concurrency process ability should be added in the OpenXDS source code to improve the hardware usage more efficiently while processing the ITI-42, ITI-18, and ITI-43 transactions. Four, this research suggests that the work should continue on adjusting the memory usage for the modules of the OpenXDS thereby using the memory resource more efficiently, e.g., the memory configuration of the JVM (Java Virtual Machine), Apache Tomcat, and Apache Axis2. Fifth, to consider if the hardware monitoring would be required in the implementing environment. These research results provided some test figures to refer to, and it also gave some tuning suggestions and future works to continue improving the performance of the OpenXDS.     

A hybrid power line and visible light communication system for indoor hospital applications

Modern hospitals are beginning to adopt E-HEALTH as efficient complements to the traditional healthcare services. To support the E-HEALTH services, a locatable, radiation-free and high-capacity communication system is urgently needed in hospitals. Power line communication (PLC) systems can use the ubiquitous power line network to power the light-emitting diode (LED) lamps while serving as the backbone network for the indoor visible light communication (VLC) systems naturally. In this article, a hybrid broadband power line and visible light communication system with orthogonal frequency division multiplexing modulation is proposed for the indoor hospital applications, which gives a brand-new solution to replace the conventional wireless communication systems in hospitals. A general-purpose system model is provided and some basic techniques to enhance system performance are also investigated. Moreover, a feasible demonstration which supports over 48 Mbps data rate within a bandwidth of 8 MHz is implemented in the laboratory.     

MPSoC based on Transport Triggered Architecture for baseband processing of an LTE receiver

Wireless communication over LTE (long term evolution) brings several design challenges to industry and academia, due to its high throughput demand. Specially in the case of hand held mobile devices where the power budget is very limited and high throughput requires more computation power. On the other hand, the industry is struggling for flexible hardware solution, a Software Defined Radio (SDR), to amortize huge costs of hardware changes to suit the continued evolution in wireless standards. In this article, an MPSoC design has been presented for the baseband processing of a 20 MHz LTE system. Transport Triggered Architecture (TTA) has been preferred over conventional DSPs/VLIW architectures as processing element (PE) of MPSoC. Processing tasks are statically scheduled. Synchronization among the PEs is based on polling of a shared memory space. In addition an approach is presented to organize I/O buffer in such a way that the stalling probability of a PE should be reduced to exploit efficiently data and task level parallelism. The total power consumption by all the PEs synthesized on 130 nm technology at 200 MHz and 1.5 V is 105.04 mW. The total energy consumption to process one subframe including carrier recovery is 0.0767 mJ. Our study shows that TTA architecture brings several improvements in conventional SIMD/VLIW architectures. TTA as contrary to other run time designs has a guaranteed performance and lower energy consumption due to the fact that all the data dependency/independency issues are resolved at compile time. Further, it is also true due to the fact that TTA has a reduced register file (RF) traffic, number of RF ports and lower overall cycle count for a given task. To the best of author’s knowledge this article is among the first few published articles on LTE receiver implementation with published figures like time, frequency, power and perhaps the first article explaining further in detail about data access pattern to process an LTE subframe, memory organization, subsystem interconnection, and synchronization.     

Improved design of an extra-high-voltage expansion substation connector through magnetic field analysis

In many countries worldwide, the energy demand is growing faster than the transmission capacity. However, due to environmental constrains, social concerns and financial costs, the construction of new power transmission lines is an arduous task. In addition, power transmission systems are often loaded close to their nominal values. Therefore, improving power transmission system efficiency and reliability is a matter of concern. This work deals with a 400 kV, 3000 A, 50 Hz extra-high-voltage expansion substation connector used to connect two substation bus bars of 150 mm diameter each. This substation connector has four aluminum wires which provide the conductive path between both bus bars. Preliminary tests showed an unequal current distribution through the wires which was mainly attributed to the proximity effect. A three-dimensional finite elements method approach was applied to improve the design and evaluate the electromagnetic and thermal behavior of both the original and improved versions of the connector. Experimental tests made under laboratory conditions have validated the accuracy of the simulation method presented in this paper, which may be a valuable tool to assist the design process of substation connectors, therefore allowing improving both the thermal performance and reliability of the redesigned connectors.     

The effect of LED lighting on color discrimination and preference of elderly people

The purpose of this study is to find out the effects of light‐emitting diode (LED) lighting on elderly people's color discrimination and preference, to improve the lighting environment for elderly people. In this study, experiments were conducted under LED lighting with two different spectra (with color‐correlated temperature [CCT] of 2800K and 6000K), and three different illuminance levels (30lx; 100lx; 1000lx). Six elderly observers (aged 55–65 years) participated in the experiments and were exposed to each lighting condition to finish one trial of a color discrimination test (Farnsworth–Munsell 100‐Hue Test) and a 7‐scale, 6‐item preference evaluation test. We conclude that elderly people perform better in color discrimination with higher CCT of LED light sources, which compensate for their decreased lens transmission at short wavelength. Their performance also increases with higher illuminance (30lx‐1000lx) of LED lighting. Meanwhile, they prefer higher illuminance, which makes them find the lighting environment more comfortable, brighter, and better for reading; but for CCT, although they feel a higher CCT is better for reading, they still have different tastes regarding CCT of light sources. © 2011 Wiley Periodicals, Inc.     

Characterisation of PZT thin film micro-actuators using a silicon micro-force sensor

This paper reports on the measurements of displacement and blocking force of piezoelectric micro-cantilevers. The free displacement was studied using a surface profiler and a laser vibrometer. The experimental data were compared with an analytical model which showed that the PZT thin film has a Young's modulus of 110 GPa and a piezoelectric coefficient d_31,f of 30 pC/N. The blocking force was investigated by means of a micro-machined silicon force sensor based on the silicon piezoresistive effect. The generated force was detected by measuring a change in voltage within a piezoresistors bridge. The sensor was calibrated using a commercial nano-indenter as a force and displacement standard. Application of the method showed that a 700 μm long micro-cantilever showed a maximum displacement of 800 nm and a blocking force of 0.1 mN at an actuation voltage of 5 V, within experimental error of the theoretical predictions based on the known piezoelectric and elastic properties of the PZT film.     

A high-throughput and high-capacity IPv6 routing lookup system

With the growing number of routing entries, IP routing lookup has become the major performance bottleneck in backbone routers. In this paper, a complete hardware-based routing lookup system is proposed to achieve high-throughput and high-capacity for IPv6. The proposed system is a cache-centric, hash-based architecture that contains a routing lookup application specific integrated circuit (ASIC) and a memory set. A hash function is used to reduce lookup time for the routing table and ternary content addressable memory (TCAM) effectively resolves the collision problem. The gate count of the ASIC, excluding the binary content addressable memory (BCAM), is about 5306 gates, using an in-house 0.18 μm CMOS single-poly six-metal standard cell library. The results of post-layout simulations show that the ASIC operates in 3.6 ns so that the routing lookup system approaches 260 Mega lookups per second (Mlps), which is sufficient for 100 Gbps networks. The memory density is good, with each routing entry requiring only 64 bits. Moreover, the routing table only needs 10.24 KB on-chip BCAM, 20.04 KB off-chip TCAM and 29.29 MB DRAM for 3.6 M routing entries in the proposed system.     

Miniature orthogonal optical scanning mirror excited by torsional piezoelectric fiber actuator

A novel optical scanner excited by a torsional piezoelectric fiber actuator is presented. The device consists of a piezoelectric fiber actuator generating torsional and longitudinal vibrations simultaneously and a specially designed metal frame transforming the two vibrations to orthogonal deflections of the mirror. Theoretical and experimental studies were performed on the structure. The changing trends of the vibration modes and resonant frequencies were obtained from finite element simulations. Samples with 1 mm × 1 mm mirrors were fabricated from PZT hollow fibers with a diameter of 1 mm and a stainless steel sheet with a thickness of 50 μm. A horizontal scanning angle of 17.9° and a vertical scanning angle of 2.6° were achieved at 6780 and 10,330 Hz under an applied voltage of 400 V_p–p.     

Clerk agent promotes consumers’ ethical purchase intention in unmanned purchase environment

This study examined the effect of the presence of an artificial individual in a purchase environment on purchase intention for products with fair-trade labels among Japanese consumers. By manipulating the presence of an artificial individual, we assessed consumers’ intentions to purchase fair-trade products under two different experimental unmanned purchase environments: the agent condition, in which task instructions were given by a female clerk-like computer graphic agent throughout the task (N = 118), and the control condition in which task instructions were given through a text box (N = 106). Results demonstrated that participants under the agent condition valuated fair trade higher than those under the control condition, although participants in both the agent and the control conditions were instructed that their responses would remain anonymous. These findings suggest that the implication of the presence of an artificial individual, such as a clerk-like agent in an unmanned purchase environment, enhances the ethicality of purchase intentions as with manned purchase environments.     

Design of embedded TCAM based longest prefix match search engine

The content addressable memory (CAM) based solutions are very useful in network applications due to its high speed parallel search mechanism. This paper presents a novel Ternary CAM (TCAM) based NAND Pseudo CMOS–Longest Prefix Match (NPC–LPM) search engine. The proposed system provides a simple hardware based solution using novel 11T TCAM cell structures and NPC word line technique, for network routers. The experiments were performed on 256 × 128 NPC–LPM system under 0.13 μm technology. The simulation result shows that the proposed design provides low power dissipation of 5.78 mW and high search speed of 315 MSearches/s under 1.3 V supply voltage. The presented NPC–LPM system meets the speed requirement of Optical Carrier (OC) 3072 with line-rate of 160 Gb/s in Ethernet networking and IPv6 protocol. The experimental results also show that the proposed system improves power-performance by 65%.     

Glucose concentration control of a fed-batch mammalian cell bioprocess using a nonlinear model predictive controller

A non-linear model predictive controller (NMPC) was investigated as a route to delivering improved product quality, batch to batch reproducibility and significant cost reductions by providing a means for better controlling the bioreactor environment in a Chinese hamster ovary (CHO) mammalian cell fed-batch process.A nonlinear fundamental bioprocess model was developed to represent the CHO mammalian cell fed-batch bioprocess under study. This developed nonlinear model aided in the configuration and tuning of a NMPC through off-line simulation. The tuned NMPC was applied to a 15 L pilot-plant bioreactor for glucose concentration fixed set-point control. Traditionally, bioprocesses are characterized by long critical process parameter (CPP) measurement intervals (24 h). However, advances in PAT have helped increase CPP measurement frequency. An in situ Kaiser RXN2 Raman spectroscopy instrument was used to monitor the glucose concentration at 6 min intervals.Glucose concentration control of a bioreactor is not a trivial task due to high process variability, measurement noise and long measurement intervals. Nevertheless, NMPC proved successful in achieving closed loop fixed set-point control in the presence of these common bioprocess operation attributes.     

Simulation of solid thermal explosion and liquid thermal explosion of dicumyl peroxide using calorimetric technique

Dicumyl peroxide (DCPO), is produced by cumene hydroperoxide (CHP) process, is utilized as an initiator for polymerization, a prevailing source of free radicals, a hardener, and a linking agent. DCPO has caused several thermal explosion and runaway reaction accidents in reaction and storage zone in Taiwan because of its unstable reactive property. Differential scanning calorimetry (DSC) was used to determine thermokinetic parameters including 700 J g^–1 of heat of decomposition (ΔH_d), 110 °C of exothermic onset temperature (T₀), 130 kJ mol^–1 of activation energy (E_a), etc., and to analyze the runaway behavior of DCPO in a reaction and storage zone. To evaluate thermal explosion of DCPO with storage equipment, solid thermal explosion (STE) and liquid thermal explosion (LTE) of thermal safety software (TSS) were applied to simulate storage tank under various environmental temperatures (T_e). T_e exceeding the T₀ of DCPO can be discovered as a liquid thermal explosion situation. DCPO was stored under room temperature without sunshine and was prohibited exceeding 67 °C of self-accelerating decomposition temperature (SADT) for a tank (radius = 1 m and height = 2 m). SADT of DCPO in a box (width, length and height = 1 m, respectively) was determined to be 60 °C. The TSS was employed to simulate the fundamental thermal explosion behavior in a large tank or a drum. Results from curve fitting demonstrated that, even at the earlier stage of the reaction in the experiments, ambient temperature could elicit exothermic reactions of DCPO. To curtail the extent of the risk, relevant hazard information is quite significant and must be provided in the manufacturing process.     

Synchronizing generalized monotonic automata

In an earlier paper, we have studied reset words for synchronizing automata whose states admit a stable linear order. Here we show that the same bound on the length of the shortest reset word persists for synchronizing automata satisfying much weaker stability restriction. This result supports our conjecture concerning the length of reset words for synchronizing automata accepting only star-free languages.     

P2P-based resource discovery in dynamic grids allowing multi-attribute and range queries

A key point for the efficient use of large grid systems is the discovery of resources, and this task becomes more complicated as the size of the system grows up. In this case, large amounts of information on the available resources must be stored and kept up-to-date along the system so that it can be queried by users to find resources meeting specific requirements (e.g. a given operating system or available memory). Thus, three tasks must be performed, (1) information on resources must be gathered and processed, (2) such processed information has to be disseminated over the system, and (3) upon users’ requests, the system must be able to discover resources meeting some requirements using the processed information. This paper presents a new technique for the discovery of resources in grids which can be used in the case of multi-attribute (e.g. {OS = Linux & memory = 4 GB}) and range queries (e.g. {50 GB < disk-space < 100 GB}). This technique relies on the use of content summarisation techniques to perform the first task mentioned before and strives at the main drawback found in proposals from literature using summarization. This drawback is related to scalability, and is tackled by means of using Peer-to-Peer (P2P) techniques, namely Routing Indices (RIs), to perform the second and third tasks.Another contribution of this work is a performance evaluation conducted by means of simulations of the EU DataGRID Testbed which shows the usefulness of this approach compared to other proposals from literature. More specifically, the technique presented in this paper improves on the scalability and produces good performance. Besides, the parameters involved in the summary creation have been tuned and the most suitable values for the presented test case have been found.     

Mechanical design and characterization of a resonant magnetic field microsensor with linear response and high resolution

A resonant magnetic field microsensor based on Microelectromechanical Systems (MEMS) technology including a piezoresistive detection system has been designed, fabricated, and characterized. The mechanical design for the microsensor includes a symmetrical resonant structure integrated into a seesaw rectangular loop (700 μm × 450 μm) of 5 μm thick silicon beams. An analytical model for estimating the first resonant frequency and deflections of the resonant structure by means of Rayleigh and Macaulay's methods is developed. The microsensor exploits the Lorentz force and presents a linear response in the weak magnetic field range (40–2000 μT). It has a resonant frequency of 22.99 kHz, a sensitivity of 1.94 V T^?1, a quality factor of 96.6 at atmospheric pressure, and a resolution close to 43 nT for a frequency difference of 1 Hz. In addition, the microsensor has a compact structure, requires simple signal processing, has low power consumption (16 mW), as well as an uncomplicated fabrication process. This microsensor could be useful in applications such as the automotive sector, the telecommunications industry, in consumer electronic products, and in some medical applications.     

A magnetoelectric energy harvester and management circuit for wireless sensor network

This paper presents an electromagnetic energy harvesting scheme by using a composite magnetoelectric (ME) transducer and a power management circuit. In the transducer, the vibrating wave induced from the magnetostrictive Terfenol-D plate in dynamic magnetic field is converged by using an ultrasonic horn. Consequently more vibrating energy can be converted into electricity by the piezoelectric element. A switching capacitor network for storing electricity is developed. The output of the transducer charges the storage capacitors in parallel until the voltage across the capacitors arrives at the threshold, and then the capacitors are automatically switched to being in series. More capacitors can be employed in the capacitor network to further raise the output voltage in discharging. For the weak magnetic field environment, an active magnetic generator and a magnetic coil antenna under ground are used for producing an ac magnetic field of 0.2–1 Oe at a distance of 25–50 m. In combination with the supply management circuit, the electromagnetic energy harvester with a rather weak power output (about 20 μW) under an ac magnetic field of 1 Oe can supply power for wireless sensor nodes with power consumption of 75 mW at a duration of 620 ms.     

Two LCOS full color projector with efficient LED illumination engine

LED-based projectors have numerous advantages compared to traditional projectors, but their light output is limited by the limited brightness of the LEDs. With an efficient illumination engine design we can build an LED projector with a moderate light output and with superior properties. In this paper we present a compact LED projector with two ‘Liquid Crystal On Silicon’ panels and four LEDs (R, 2 × G, B). We use two panels instead of the classical three panels and will still have the same performance and moreover a reduced volume and cost. The illumination system consists of a custom made monolithic component (GTLP) that is combining many functions. We have also integrated some methods to increase the brightness of the LEDs by pulsing them. Additional methods, such as using an extra PBS to combine both color channels, are implemented to increase the contrast. After investigating the promising simulation results (119 lm D65 light with very high contrast and uniformity), we built a demonstrator setup. Our demonstrator produces a moderate light output (37.3 lm) on screen with a sufficient contrast ratio and a very good uniformity. In spite of semi color sequential working, the color breakup and crosstalk are negligible. The difference in performance and possible improvements will be discussed in the paper.