Types Of Digital Systems Research Articles

Simulation and Characterization of an Inverter Logic Gate by Utilizing InGaAs-Based Planar Devices

Electronic circuits known as logic gates can perform basic logical operations like inverters, AND, and OR gates. These logic gates serve as the basis for digital electronics, and they are a common component in various electronic devices, such as computers, smartphones, and other types of digital systems. This research presents an inverter logic gate made of planar devices, which have significantly simpler structures than multi-layered transistors and diodes, namely the self-switching diode (SSD) and side-gated transistor (SGT). The inverter logic gate is realized by simply connecting both SSD and SGT in parallel. The electrical characteristics and performances of the inverter logic gate are assessed based on InGaAs material using SILVACO Inc.'s ATLAS device simulator software. The simulation results show that the functionality of the proposed planar inverter is comparable to that of a conventional inverter logic gate based on the standard truth table of the device. This has demonstrated the feasibility of building logic gates using a combination of SSDs and SGTs. In addition, the planar structure of SSD and SGT allows for a relatively low-cost device fabrication process as well as offering a high-frequency operation due to low parasitic elements in the devices.

Internet of Things Assisted Monitoring Using Ultrasound-Based Gesture Recognition Contactless System

In the last decade, we have seen an increase in the use of digital technologies in our daily lives, including advanced systems such as mobile applications, smart digital kiosks for intelligent retailing, touch screens for ordering food, or simple implementations such as the ticket machines in the butchers. However, from the perspective of interaction design, those sensing systems suffer from several constraints and limitations such as, low usability and poor hygiene. For example, the elderly or the disabled normally have huge difficulties when interacting with these types of digital systems. Moreover, the recent SARS-CoV-2 pandemic has made us rethink the way we interact with the digital devices. Hence, in this paper, we present a novel solution for digital interaction through a contactless model. This system can provide human gesture recognition and therefore it can be integrated into others to achieve contactless control. We have implemented a prototype based on cost efficient sensors to validate the idea’s feasibility. Moreover, a sequence of real world experiments has also been conducted to evaluate its performance. This system is composed with 1) a 3d printed grid of ultrasound sensors to capture the distance information from a human body; 2) software to analyse the data for gesture predictions. This analysis results will be transformed into control commands to interact with the attached system. The experimental results have shown that the proposed system is capable of providing a contactless Human Computer Interaction (HCI), and also has a great opportunity to replace existing touching interaction manner with a remote control scheme.

Clinical Technique: Digital Radiography in Exotic Pets—Important Practical Differences Compared with Traditional Radiography

The future of radiography will be digital. In exotic pet radiography, where some of the animals have a very low body weight and anatomic structures can be small, detail rendition plays an important feature in image quality. Veterinarians should be familiar with the technical principles, image quality criteria, and radiation exposure issues associated with the various types of digital systems currently available. This article discusses basic principles of digital radiography, technical solutions, and selected parameters characterizing detectors, processing, and monitors. An overview of reported experiences is given, and results from experimental clinical studies are reviewed to evaluate the current options and limitations in applying digital radiography to exotic pet medicine.

Globicomp—doing ubicomp differently: introduction to the special issue

The bulk of the research community’s work to date has been focussed on the so-called ‘developed’ world— contexts where there are already well-established technical infrastructures and digital resources. These contexts have users who have relatively high level of computer literacy, typically have a high degree of textual literacy and have undergone a formal education. Examples include sophisticated ‘smart’ homes with digital noticeboards and even interactive fridge doors [3]; embedded technologies for amusement parks [2]; and, cities and urban dwellers with time to, ‘‘marvel at mundane everyday experiences and objects that evoke mystery, doubt, and uncertainty. How many newspapers has that person sold today? When was that bus last repaired? How far have I walked today? How many people have ever sat on that bench? Does that woman own a cat? Did a child or adult spit that gum onto the sidewalk?’’ [1]. But pervasive digital technology is no longer the preserve of the developed world. The ITU reports that in the developing world, some 68% of people have access to the cellular network [4]. Furthermore, 90% of the world’s population, and 80% of its rural population, live within range of the cellular network. Therefore, there are hundreds of millions of users, and billions to come in the next 5 years, in places like India, China, and Africa, whose first, and perhaps only, experience of computing will be in the form of mobile and other ubicomp technologies. This Theme Issue is about the billions of people who previously lay outside the domain of digital technology. Take Sambasivan et al.’s contribution, for instance. It examines how technology is diffusing through resourcepoor groups in the urban slums of India. In particular, they examine how the constraints built into the technologies are overcome, as these new users come to understand the technology and appropriate it for their situations. And it is not just ‘developing’ countries. What about those who were previously marginalised in our ‘developed’ world—the urban poor, the ill-educated, the homeless, the computer non-literate; i.e., those without access to what many of us take as essential digital infrastructure? Woelfer and Hendry’s paper, then, looks at the types of digital systems required to support young homeless people in Seattle, WA; a city that is one of the homes of digital innovation globally, yet through this work, we see many of its citizens have hitherto been bypassed by digital progress. Many of these users will never live in the sorts of home, or work in the types of office, or daydream in the parks, or take a day-off for the sorts of amusement park envisaged by earlier ubicomp research. A new discipline, currently called HCI4D, is trying to re-imagine how we conduct user research for these new communities of users. As this research grows, we find that we have to reconsider the methods we have held dear and challenge the assumptions that underlie them—for example, how does one do participatory design with someone who has never seen a computer interface before? Putnam et al. tackle this issue in their contribution, seeking to find methods appropriate for creating designs for these new groups of users. In her G. Marsden ICT4D Centre, University Cape Town, Cape Town, South Africa e-mail: gaz@acm.org

Artifacts seen during CT pelvimetry: implications for digital systems with scanning beams.

During computed tomography (CT) pelvimetry of two pregnant women, bony abnormalities of the fetuses were noted on the scout images that were not confirmed at delivery. To explore the cause of these artifacts, specimen long bones were manipulated in various ways during CT scout imaging. Artifacts like those seen during in vivo imaging were found to be caused by motion of the object. The CT scout view is an example of an image produced by a digital system that uses a scanning beam. This type of digital system is being used for several types of body imaging including screening for scoliosis and chest radiography. Attention to motion artifacts should decrease diagnostic errors and aid further development of these systems.

A Functional Approach to Testing Bit-Sliced Microprocessors

Bit-sliced microprocessors are representative of an important class of LSI components that can be interconnected in a regular way to construct many useful types of digital systems. This paper develops an analytic test generation methodology for bit-sliced systems. A formal model C for a 1-bit bit-sliced microprocessor is defined which has the main features of many commercially available microprocessors. Using a functional fault model instead of the usual stuck-line fault model, a technique is presented for deriving a complete and near-minimal sequence of tests for C. The basic cell C is extended to form two more general cells Ck and Ck. n. Ck is a k-bit version of C, while Ck, n is Ck with an n × k-bit scratchpad RAM. The internal structure of C4,16 closely resembles that of the AMD 2901 processor slice. Test sequences for these cells are derived in much the same way as for C. It is shown that the test sequence for a single cell (C, Ck, or Ck, n) can easily be extended to a test sequence for an array of N identical cells with no increase in the number of tests required. It is observed that for test generation purposes, bit-sliced microprocessors can be viewed as C-testable iterative logic arrays, which require a constant number of test patterns independent of array size. Some new results on test generation for C-testable systems are presented, as well as a method for modifying iterative logic arrays to make them C-testable.