L-band and SHF multiple access schemes for the MSAT system

The first generation of the Canadian Mobile Satellite (MSAT) system, planned to be operational in the early 1990s, will provide voice and data services to land, aeronautical, and maritime mobile terminals within the Canadian land mass and its territorial waters. The system will be managed by a centralized Demand Assignment Multiple Access (DAMA) control system. Users will request a communication channel by communicating with the DAMA Control System (DCS) via the appropriate signalling channels. Several access techniques for both L-band and SHF signalling channels have been investigated. For the L-band, Slotted Aloha (SA) and Reservation Aloha (RA), combined with a token scheme, are discussed here. The results of Telesat studies to date indicate that SA, when combined with token scheme, provides the most efficient access and resource management tool in a mobile propagation environment. For SHF signalling channels, slim time division multiple access (TDMA) and SA have been considered as the most suitable candidate schemes. In view of the operational environment of the SHF links, provision of a very short channel access delay and a relatively high packet success rate are highly desirable. Studies carried out generally favor slim-TDMA as the most suitable approach for SHF signalling channels

How do patients with end-stage ankle arthritis decide between two surgical treatments?:A qualitative study

To examine how patients decide between ankle fusion and ankle replacement in end-stage ankle arthritis

The impact of Linguistic knowledge on Learner Strategy Deployment

It is generally accepted that linguistic knowledge is a key element in the comprehension of reading of texts in a second language (L2). Research on the ‘threshold level' argues that learners need to reach to a certain level of L2 proficiency in order to be able to understand printed text. However, it is still not clear when and how learners reach the threshold level and, when they do, which reading skills are sensitive to this proficiency. It is argued that Strategy Based Instruction (SBI) may provide beginning level students with tools to cope with challenges of reading. However, although learners are able to use learner strategies as guiding mechanisms while reading, a lack of linguistic knowledge can short-circuit the deployment of such. This paper presents extracts from think-aloud protocols that were conducted as part of a quasi-experimental study carried out with 12-year-old secondary school students in Cyprus. Strategy deployment was analysed in terms of order, complexity and simplicity, symbiotic relationships and sophistication. The findings show that learners, despite their weak linguistic knowledge, were able to use certain strategies to cope with difficulties. Nevertheless, examples are also offered which suggest that weak linguistic knowledge can sometimes get in the way of successful strategy deployment; thus providing evidence to support the threshold hypothesis. It is argued that SBI can offer a guiding mechanism for beginner level students' language learning. Such students can use strategies as tools to cope with the challenges of reading texts. However, a certain level of proficiency is necessary if students are to be able to draw on these strategies

ERP System Solutions for Small Companies: Readiness & Selection

Over the past decade almost all of major businesses in the US have implemented Enterprise Resource Planning (ERP) systems to run daily business operations.  However, a complex ERP system, if not implemented properly,  can easily disrupt, or sometimes cripple, the flow  of the manufacturing  and other operations.  While large organizations  are in a  unique position  to implement  a good     RP  system,  most  small  companies  cannot  afford  the acquisition  and implementation cost of a big name ERP system. Therefore, smaller organizations rely on vendors with affordable, but not necessarily proven, ERP systems. To help small businesses avoid implementation problems and system glitches after ERP implementation, two proactive initiaves are recommended. ERP readiness and ERP selection. This article organizes a checklist for each initiative so that small companies are better prepared to overcome implementation challenges and their expectations are more aligned with the norm of an ERP implementation

Experimental Test, Model Validation, and Viability Assessment of a Wave-Rotor Constant-Volume Combustor

Design and testing of a wave-rotor constant-volume combustor achieved stable combustion at near-atmospheric inlet conditions and demonstrated the potential of pressure-gain combustion using a wave rotor. An experiment rig with a motor-driven, room-temperature rotor with large thermal mass operated for short durations within heating limits of extensive in-passage rotating instrumentation. Over 30 successful tests were completed, including a 3 s run amounting to about 2000 individual firing events. Fast deflagrative combustion was observed with varied ethylene fuel distribution in the passages, showing good combustor operability, insensitive to leakage. Remarkably high flame speeds and a net pressure gain were indirectly indicated from measurements. A time-marching, spatially one-dimensional numerical model of gas dynamics and combustion was used for aerothermodynamic design, applying loss models previously calibrated with pressure-exchange nonreacting wave-rotor experiments. Major features and trends of the measured gas dynamic and combustion processes showed good agreement with predictions and validated current design methods. Different fuel distributions were tested to better calibrate ignition and combustion submodels. Simulations illustrate the likely explanations for cases with and without observed ignition, spillage during the filling process, and mixture requirements for consistent torch ignition. The viability of wave rotors for realizing a pressure-gain combustor is discussed

Nano-Resolution Visual Identifiers Enable Secure Monitoring in Next-Generation Cyber-Physical Systems

Today's supply chains heavily rely on cyber-physical systems such as intelligent transportation, online shopping, and E-commerce. It is advantageous to track goods in real-time by web-based registration and authentication of products after any substantial change or relocation. Despite recent advantages in technology-based tracking systems, most supply chains still rely on plainly printed tags such as barcodes and Quick Response (QR) codes for tracking purposes. Although affordable and efficient, these tags convey no security against counterfeit and cloning attacks, raising privacy concerns. It is a critical matter since a few security breaches in merchandise databases in recent years has caused crucial social and economic impacts such as identity loss, social panic, and loss of trust in the community. This paper considers an end-to-end system using dendrites as nano-resolution visual identifiers to secure supply chains. Dendrites are formed by generating fractal metallic patterns on transparent substrates through an electrochemical process, which can be used as secure identifiers due to their natural randomness, high entropy, and unclonable features. The proposed framework compromises the back-end program for identification and authentication, a web-based application for mobile devices, and a cloud database. We review architectural design, dendrite operational phases (personalization, registration, inspection), a lightweight identification method based on 2D graph-matching, and a deep 3D image authentication method based on Digital Holography (DH). A two-step search is proposed to make the system scalable by limiting the search space to samples with high similarity scores in a lower-dimensional space. We conclude by presenting our solution to make dendrites secure against adversarial attacks

Electronic Health Records (EHR) Implementation and Post Implementation Challenges

The US Healthcare Industry lags behind other industries in its use of technologies for process improvement and improvement in quality of services for its patients. Globally, United States is significantly behind some European and Australian countries in implementation of EHR. While the federal government is now mandating this change and also offering incentive programs, healthcare providers remain slow to comply because of challenges they face regarding EHR implementation. This paper discusses EHR architecture, presents implementation challenges, provides a case study and offers future research ideas. The information provided in this research could be beneficial for successful EHR implementation

Valuable biomolecules from nine North Atlantic red macroalgae:Amino acids, fatty acids, carotenoids, minerals and metals

In modern society, novel marine resources are scrutinized pursuing compounds of use in the medical, pharmaceutical, biotech, food or feed industry. Few of the numerous marine macroalgae are currently exploited. In this study, the contents of nutritional compounds from nine common North Atlantic red macroalgae were compared: the lipid content was low and constant among the species, whereas the fatty acid profiles indicated that these species constitute interesting sources of polyunsaturated fatty acids (PUFA). The dominating essential and non-essential amino acids were lysine and leucine, aspartic acid, glutamic acid, and arginine, respectively. The amino acid score of the nine algae varied from 44% to 92%, the most commonly first limiting amino acid being histidine. Lutein, β-carotene, and zeaxanthin were the identified carotenoids. Contents of all macro and trace minerals, with the exception of phosphorus, were higher than those described for conventional food. Low sodium/potassium ratios (0.08 - 2.54) suggested a potential for using the ash fraction for sodium salt replacement. The algae constituted rich sources of carbohydrates (40% to 71% of DM) which show their potential for a broader commercial exploitation. In some species, the concentrations of arsenic, cadmium, and lead exceeded limit values for application in food or feed. In conclusion, the nine algae represent promising potential sources of health promoting additives for human and animal diets, in whole or in a biorefinery concept

E-ful llment: the strategy and operational requirements

Abstract An e-ful llment system is designed to meet the high order volume and stringent customer service requirements of global business-to-consumer e-commerce. The system converts the traditional warehouse into a multi-channel e-ful llment center. In the e-commerce environment, some of the toughest decisions must be made on little or no hard information. In this study, the nature of e-business and the typical ful llment process are discussed. The authors further examine the strategy and operational requirements for e-ful llment. This article is concluded with the implication of a successful e-ful llment system, a suggested design of an e-ful llment center, and the future research focuses