Lesser Bear: A lightweight process library for SMP computers—scheduling mechanism without a lock operation

We have designed and implemented a lightweight process (thread) library called ‘Lesser Bear’ for SMP computers. Lesser Bear has thread‐level parallelism and high portability. Lesser Bear executes threads in parallel by creating UNIX processes as virtual processors and a memory‐mapped file as a huge shared‐memory space. To schedule thread in parallel, the shared‐memory space has been divided into working spaces for each virtual processor, and a ready queue has been distributed. However the previous version of Lesser Bear sometimes requires a lock operation for dequeueing. We therefore proposed a scheduling mechanism that does not require a lock operation. To achieve this, each divided space forms a link topology through the queues, and we use a lock‐free algorithm for the queue operation. This mechanism is applied to Lesser Bear and evaluated by experimental results. Copyright © 2002 John Wiley & Sons, Ltd.     

CGLIB—a constraint‐based graphics library

CGLIB is a high‐level graphics library for B‐Prolog, a constraint logic programming system. The library provides primitives for creating and manipulating graphical objects and a set of constraints including not‐overlap, grid, table and tree constraints that facilitate the specification of the layouts of objects. The library adopts a construct called action rules which is available in B‐Prolog for creating agents and programming interactions among agents or between agents and the user. The library is a fully working system implemented in B‐Prolog, Java and C. It can be used in many areas such as drawing editors, interactive user interfaces, document authoring, animation, information visualization, intelligent agents and games. The high‐level abstraction of the library and the use of constraints and action rules in the specification of layouts and behaviors can significantly enhance the productivity of the development of graphics. We demonstrate through several examples the effectiveness of the library as a tool for developing graphics‐rich and interactive user interfaces. Copyright © 2003 John Wiley & Sons, Ltd.     

Object‐process based graphics recognition class library: principles and applications

We have developed a Graphics Class Library (GCL) for graphics recognition using the object‐process methodology and object‐oriented implementation. The purpose of the library is to supply generic code for graphics recognition algorithms to be used as ready made and easily extendible components in future systems. The library consists of reusable classes of graphic objects that appear in engineering drawings as well as in other classes of line drawings. A generic integrated graphics recognition algorithm is at the basis of the library, serving useful standard operations required for graphics recognition applications. Copyright © 1999 John Wiley & Sons, Ltd.     

Low‐cost wearable low‐vision aid using a handmade retinal light‐scanning microdisplay

Abstract— The Wearable Low Vision Aid (WLVA) is a portable system that uses machine vision to track potential walking hazards for the visually impaired. A scanning fiber display couples a laser diode to a vibrating optical fiber that projects a virtual image onto the retina to display warning icons that the visually impaired can recognize. Initial low‐vision subject testing has given promising results for this low‐cost assistive device.     

Interface and bulk effects for bias—light‐illumination instability in amorphous‐In—Ga—Zn—O thin‐film transistors

Abstract— Positive‐current‐bias (PB) instability and negative‐bias—light‐illumination (NBL) instability in amorphous‐In—Ga—Zn—O (a‐IGZO) thin‐film transistors (TFTs) have been examined. The channel‐ thickness dependence indicated that the Vth instability caused by the PB stress is primarily attributed to defects in the bulk a‐IGZO region for unannealed TFTs and to those in the channel—gate‐insulator interface for wet‐annealed TFTs. The interface and bulk defect densities (Dit and Nss, respectively) are Dit = 4.8 × 10¹¹ cm^?2/eV and Nss = 7.0×10¹⁶ cm^?3/eV for the unannealed TFT, which increased to 5.2×10¹¹ cm^?2/eV and 9.8×10¹⁶ cm^?3/eV, respectively, by the PB stress test. These are reduced significantly to Dit = 0.82×10¹¹ cm^?2/eV and Nss = 3.2×10¹⁶ cm^?3/eV for the wet‐annealed TFTs and are unchanged by the PB stress test. It was also found that the photo‐response of a‐IGZO TFTs begins at 2.3 eV of photon excitation, which corresponds to subgap states observed by photoemission spectroscopy. The origin of the NBL instability for the wet‐annealed TFTs is attributed to interface effects and considered to be a trap of holes at the channel‐gate—insulator interface where migration of the holes is enhanced by the electric field formed by the negative gate bias.     

Enhancement of blue‐light‐emission properties for OLED displays by using a polarized light‐recycling structure

Abstract— The blue‐light‐emission properties of organic light‐emitting‐diode (OLED) displays must be enhanced to meet the requirements for color purity and luminous efficiency because few blue‐light‐emitting materials meet these requirements. This is particularly true for polymeric and phosphorescent light‐emitting materials. To attain the required purity and efficiency, a polarized‐light‐recycling structure for blue light that is called a blue enhanced circular polarizer (BECP) has been developed. The principle of the structure and the fabricated prototype device is described and it is shown that the structure increases blue‐light intensity and color purity, improves efficiency, provides a wide color gamut, and limits ambient‐light reflection.     

Reduced‐cost microwave filter modeling using a two‐stage Gaussian process regression approach

A technique for the reduced‐cost modeling of microwave filters is presented. Our approach exploits variable‐fidelity electromagnetic (EM) simulations, and Gaussian process regression (GPR) carried out in two stages. In the first stage of the modeling process, a mapping between EM simulation filter models of low and high fidelity is established. The mapping is subsequently used in the second stage, making it possible for the final surrogate model to be constructed from training data obtained using only a fraction of the number of high‐fidelity simulations normally required. As demonstrated using three examples of microstrip filters, the proposed technique allows us to reduce substantially (by up to 80%) the central processing unit (CPU) cost of the filter model setup, as compared to conventional (single‐stage) GPR—the benchmark modeling method in this study. This is achieved without degrading the model generalization capability. The reliability of the two‐stage modeling method is demonstrated through the successful application of the surrogates to surrogate‐based filter design optimization. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:453–462, 2015.     

A plastic holographic waveguide combiner for light‐weight and highly‐transparent augmented reality glasses

There is a high demand for light‐weight, stylishly designed augmented reality (AR) glasses with natural see‐through capabilities for the wide‐spread distribution of novel wearable device to general consumers. We have successfully developed a unique production process of a holographic waveguide combiner that enables us to laminate holographic optical elements (HOEs) onto a plastic substrate with optical grade quality. The plastic substrate waveguide combiner has a number of advantages over conventional glass substrate combiners; the plastic substrate makes AR glasses lighter in weight and unbreakable. With the lamination process of HOEs, we can apply them to a various designs to satisfy general customers' wide range of preferences for the style. We also potentially made it possible for the holographic waveguide combiner to be produced in larger volumes at lower costs by using our novel roll‐to‐roll hologram recording and laminating process. In this paper, we present our approach of the plastic substrate HOE production process for AR glasses.     

Fabrication of flexible organic light‐emitting‐diode display with a flexible color filter driven by In—Ga—Zn—Oxide TFTs

Abstract— A novel flexible active‐matrix organic light‐emitting‐diode (OLED) display fabricated on planarized stainless—used‐steel substrates with a resolution of 85 dpi in a 4.7‐in. active area has been demonstrated. Amorphous indium—gallium—zinc—oxide thin‐film transistors were used as the backplane for the OLED display with high device performance, high electrical stability, and long lifetime. A full‐color moving image at a frame frequency of 60 Hz was also realized by using a flexible color filter directly patterned on a plastic substrate with a white OLED as the light source.     

Edison-N — an Edison implementation for a network of microcomputers

This paper describes an experimental implementation of the Edison programming language for a network of microcomputers based on the Z-80 microprocessor. The resulting Edison-N system allows parallel execution of concurrent processes. Its aim is to assist in teaching the principles of concurrent programming.     

Current programming pixel circuit and data‐driver design for active‐matrix organic light‐emitting diodes

Abstract— We propose a new pixel design for active‐matrix organic light‐emitting diodes (AMOLEDs) employing five polycrystalline thin‐film transistors (poly‐Si TFTs) and one capacitor, which decreases the data current considerably in order to reduce the charging time compared with that of conventional current‐mirror structures. Also, the new pixel design compensates the threshold‐voltage degradation of OLEDs caused by continuous operation and the non‐uniformity of poly‐Si TFTs due to excimer‐laser annealing. The proposed pixel circuit was verified by SPICE simulation, based on measured TFT and OLED characteristics. We also propose current‐data‐driver circuitry that reduces the number of shift‐register signals for addressing the current data driver by one‐half.     

Fine metal mask material and manufacturing process for high‐resolution active‐matrix organic light‐emitting diode displays

Manufacturing fine metal mask (FMM) is one of the biggest hurdles to realize the ultra‐high definition (UHD) grade AMOLED displays for smartphone and augmented reality (AR). We have developed the state‐of‐the‐art material and processing technology to achieve 800ppi or higher‐resolution FMMs. The Invar thinning and the thermal damage‐free laser ablation process realized us achieving the FMM for UHD displays.     

A compact uniplanar antenna for nine‐band LTE/WWAN operation in tablet computers

A compact uniplanar dual wideband antenna for tablet computers is presented. The proposed antenna provides full coverage of LTE700/2300/2500, GSM850/900/1800/1900, UMTS2100, Bluetooth, and 2.4‐GHz WLAN bands with a very small foot print 30 × 10 mm². The antenna has uniplanar structure and is easy to fabricate on single side of 0.8‐mm thick FR4 substrate. This is achieved through three optimized strips: a feeding strip, an inductively coupled inverted L‐shaped strip, and a shorted strip embedded with SMT components. The proposed design supports more than eight operating bands in 3:1 VSWR standard, exhibiting positive gains over all nine bands of operation and 80%–90% radiation efficiency in the higher LTE and WWAN bands. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:496–502, 2016.     

FirstSTEP process modeler — a CIMOSA-compliant modeling tool

Since its market release in late 1994, the FirstSTEP toolset developed by Interfacing Technologies of Montreal, Canada has been proven to be one of the most practical solutions for business process management initiatives. Being a methodology independent enterprise modeling and simulation application, FirstSTEP has been adopted by industry leaders from such diversified sectors as manufacturing, finance, telecom, healthcare, public, and others. Its concept and approach are compatible to the framework. Most notably is the user front-end simplicity that has enabled its acceptance by the typical business manager who is not usually academic in his/her approach. The paper presents the FirstSTEP tool suite, its concept and approach and demonstrates its capabilities using an application with a most recent FirstSTEP user — America Online.     

HARTEX—a safe real‐time kernel for distributed computer control systems

A hard real‐time kernel is presented for distributed computer control systems (DCCS), highlighting a number of novel features, such as integrated scheduling of hard and soft real‐time tasks as well as tasks and resources; high‐performance time management supporting safe DCCS operation in a hard real‐time environment; synchronization and communication featuring event notification via vector semaphores and transparent communication through implicit (content‐oriented) message addressing. Conventional queues have been substituted by Boolean vectors and vector processing techniques throughout the kernel, resulting in efficient and highly deterministic behaviour, which is characterized by very low overhead and constant execution time of kernel operations, independent of the number of tasks involved. Copyright © 2001 John Wiley & Sons, Ltd.     

The application kernel approach—a novel approach for adding SMP support to uniprocessor operating systems

The current trend of using multiprocessor computers for server applications requires operating system adaptations to take advantage of more powerful hardware. However, modifying large bodies of software is very costly and time consuming, and the cost of porting an operating system to a multiprocessor might not be motivated by the potential performance benefits. In this paper we present a novel method, the application kernel approach, for adaption of an existing uniprocessor kernel to multiprocessor hardware. Our approach considers the existing uniprocessor kernel as a ‘black box’, to which no or very small changes are made. Instead, the original kernel runs operating system services unmodified on one processor whereas the other processors execute applications on top of a small custom kernel. We have implemented the application kernel for the Linux operating system, which illustrates that the approach can be realized with fairly small resources. We also present an evaluation of the performance and complexity of our approach, where we show that it is possible to achieve good performance while at the same time keeping the implementation complexity low. Copyright © 2006 John Wiley & Sons, Ltd.     

Work stealing for GPU‐accelerated parallel programs in a global address space framework

Task parallelism is an attractive approach to automatically load balance the computation in a parallel system and adapt to dynamism exhibited by parallel systems. Exploiting task parallelism through work stealing has been extensively studied in shared and distributed‐memory contexts. In this paper, we study the design of a system that uses work stealing for dynamic load balancing of task‐parallel programs executed on hybrid distributed‐memory CPU‐graphics processing unit (GPU) systems in a global‐address space framework. We take into account the unique nature of the accelerator model employed by GPUs, the significant performance difference between GPU and CPU execution as a function of problem size, and the distinct CPU and GPU memory domains. We consider various alternatives in designing a distributed work stealing algorithm for CPU‐GPU systems, while taking into account the impact of task distribution and data movement overheads. These strategies are evaluated using microbenchmarks that capture various execution configurations as well as the state‐of‐the‐art CCSD(T) application module from the computational chemistry domain. Copyright © 2016 John Wiley & Sons, Ltd.     

Development of a color‐tunable polychromatic organic‐light‐emitting‐diode device for roll‐to‐roll manufacturing

A flexible vertically stacked flexible polychromatic color‐tunable OLED has been developed by means of low resistive intermediate electrode technology. The polychromatic OLED has a capability to show 16 million colors with 105% National Television Committee Standard (NTSC) color reproduction. The device can produce arbitrary shape with arbitrary colors, suitable for artistic expressions, just as many as those used in information displays. Independently controlled red, green, and blue light‐emitting layers are stacked vertically. With conventional indium tin oxide technology, because of the temperature restriction, it was quite difficult to achieve low resistance on plastic substrate. The reported numbers were all more than 80 Ω/□. According to the surface mobility control using Fick's law analysis, low sheet resistance 7.34 Ω/□ on plastic film was developed. At first, flexible 7.17 cm² transparent OLED was fabricated for the performance confirmation of transparent electrode. And then polychromatic color‐tunable OLED with the same size were successfully fabricated on plastic. With optical length optimization for each color stack of polychromatic OLED, more than 100% color reproduction in National Television Committee Standard was achieved by stack design. The polychromatic device can be used for colored illumination, as well as for organic‐light‐emitting display pixels for three times emission than conventional pixel design. The device is fabricated on plastic substrate so that the polychromatic organic‐light‐emitting‐diode device is manufacturable with roll‐to‐roll production line.     

Design of a prism light‐guide plate for an LCD backlight module

Abstract— This paper describes the development of a design method for a prism pattern for an LCD light‐guide plate to improve the uniformity of its exiting light. First, the prism surface of the light‐guide plate is divided into several equal regions. With the aid of ASAP simulation, this method uses the mean light flux of all regions as a reference value to adjust the distribution density of the prism pattern for each region. Curve fitting is then performed to provide a smoothly changing distribution density for further improvement of the exiting light uniformity. ASAP results demonstrate that the illuminance uniformity for a 2.5‐in. light‐guide plate is substantially improved from 45% to 90.9% by using this design method.