Miracle-dz/UniFAR-FTUs huggingface dataset:
Condition for the Coverage and Connectivity of Wireless Sensor Network

The topology attributes of both connectivity and coverage in a wireless sensor network depend on the spatial distribution and transmission range of the nodes. This paper proposes an analytical expression of the required critical transmission range of a node, for a given node density, to create an almost surely connected network. Equivalently, if the maximum range of the nodes is given, it can estimate effectively the number of nodes needed to cover a certain connected network. With experimental tests, the method is proved to achieve guaranteed degrees of coverage and connectivity, valuable for researchers in this area.
Phase noise contribution of the phase/frequency detector in a digital PLL frequency synthesiser

A theoretical basis for the figure of merit method used to quantify the phase noise plateau of a PLL frequency synthesiser is described. Analyses are developed both to calculate the in-band phase noise of a given synthesiser architecture and to predict the figure of merit from the phase/frequency detector parameters. A range of experimental results is provided to validate the theory.
Monitoring of resistance spot weld quality using electrode vibration signals

Electrode vibrations can reflect resistance spot weld nugget formation, but this has not been widely appreciated so far. Although a displacement sensor can be used to detect the electrode vibrations, it is not suitable for industrial applications for its inconvenient installation and high cost. In this paper, an electrode displacement between two electrodes and acceleration signals from the upper and lower electrodes were measured using a displacement sensor and a dual accelerometer respectively, and the vibration amplitude curves were extracted from the collected signals through data processing and the results showed that they are very consistent. The effect of welding current on an electrode vibration curve monitored using the dual accelerometer was studied, and the results showed that electrode vibrations can be used to monitor weld quality, such as no weld, sticking weld, small weld, good weld and expulsion. Moreover, the monitoring of resistance spot weld quality using electrode vibration signals under abnormal welding conditions, such as shunting, small edge distance and greasy surface, was also performed. This research will provide references for monitoring resistance spot weld quality using the accelerometer method.
Nonlinear Generation Of High Power Millimeter Wave Optical Intensity Modulation

Practical methods to generate high power, optical intensity modulation, from a laser diode, at mm wave frequencies may be useful for a number of optical transmission, radar, signal processing, or component testing applications. While source bandwidths exceeding 20 GHz have been achieved by direct modulation of diode lasers[1], or by using external waveguide modulators[2], in general these devices fall short of the region between 30 and 100 GHz, which is of some interest. In this paper we discuss an interferometric method, the FM sideband technique, which has the following important features: 1 - intensity modulation from a laser diode is generated at frequencies which are much greater than the direct modulation bandwidth of the laser diode, 2 - the maximum frequency response is limited by detector rather than source bandwidth and, 3 - this technique is extremely efficient (in may cases, it is more efficient than direct modulation of a laser diode), and thus can generate signals with high power. Using the FM sideband technique a 40 GHz optical carrier signal has been generated by direct modulation of a laser diode at 13 GHz. While the maximum frequency we could observe was limited by the availability of high frequency measurement electronics, frequencies on the order of 100 GHz should be obtainable using suitable detectors[3,4]. We have also demonstrated upconversion of a narrow band baseband information channel to a 11 GHz carrier, and high frequency detector characterization using the FM sideband technique[5].
A Test of Intra-versus Inter-Modality Interference as a Function of Time Pressure in a Warfighting Simulation

Useful task managers that can effectively monitor, prioritize, and distribute tasks to our warfighters are being sought. A critical need for the creation of task managers is an understanding of the conditions that lead to successful multi-tasking. The present study is an initial empirical step at increasing this understanding within the environment of a Command and Control (C2) Dynamic Targeting Cell (DTC). We examined operator performance and workload for participants deploying assets to attack enemy targets and their ability to concurrently monitor auditory or visual communications in three conditions of time-pressure (low, medium, and high). Results showed a significant impact in high time-pressure conditions, especially when operators had to process multiple sources of information from the same modality. These findings are a critical step as to understanding multi-tasking performance in C2 environments in general and with regard to communication and spatial monitoring tasks in particular.
Using an International Experience to Bridge the Gap Between Culture and Science Literacy

Today’s agricultural industry is charged with feeding a growing population, which means producing larger quantities of food and marketing the food worldwide. Future employers seek graduates that have global perspectives. To mitigate students’ lack of international knowledge, many higher education institutions are providing students an opportunity to participate in study abroad programs. The purpose of this study was to explore how an international experience in South Africa impacted participants’ perceptions of South African culture, global agriculture, and science. Seven reoccurring themes emerged from the data: a) adaptability (pre-experience), b) enhanced communication skills (both pre and post experience), c) an attainment of diverse/broadened academic agricultural knowledge (both pre and post experience), d) risk taking (post-experience), e) intercultural competency and global awareness (both pre and post experience), f) critical thinking skills (post-experience), and g) career enhancement (post-experience). Findings indicate an international experience should integrate cultural learning, academic learning, and should be applied to the participant’s future career. Keywords: international experiences; science literacy; cultural learning; study abroad
Sharing quality information in a dual-supplier network: a game theoretic perspective

We study a two-level supply chain consisting of two competing suppliers and one buyer. Both suppliers experience some level of uncertainty on product quality, which, in turn, leads to additional cost on the buyer's side. We evaluate the benefits of sharing information on suppliers’ product quality with the buyer. Specifically, if a supplier shares its quality inspection result of sampled products on an order basis, how should the buyer use this information to reduce quality uncertainty in the products he received? Will quality information sharing benefit the supplier(s) as well? We develop an analytical model to investigate each member's performance with/without quality information sharing. We also develop equilibrium strategies for the suppliers with quality information sharing. Our results show that the buyer always benefits from quality information sharing. From the supplier's perspective, sharing quality information with the buyer impacts its market share. Moreover, whether to share its quality information depends on the supplier's product quality level and price level.
1-Phase Induction Motor Control Using Modified H-Bridge 11-Level Inverter

This paper proposes to develop a model of 1-phase induction motor control using modified H-bridge 11-level inverter. This work notifies a multilevel inverter using a H-bridge output stage with four bidirectional auxiliary switches for an induction motor. The inverter is capable of producing eleven levels of output-voltage levels (+Vdc/5, +2Vdc/5, +3Vdc/5, +4Vdc/5, +Vdc, ‘0’ level, -Vdc/5, -2Vdc/5, -3Vdc/5, -4Vdc/5, -Vdc) from the DC supply. Theoretical predictions of the proposed system are validated using simulation in MATLAB simulink.
FINAL REPORT ON CONTROL ALGORITHM TO IMPROVE THE PARTIAL-LOAD EFFICIENCY OFSURFACE PM MACHINES WITH FRACTIONAL-SLOT CONCENTRATED WINDINGS

Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque amplitudes as well as significantly increasing the machine power density [3-5] compared to SPM machines using conventional distributed windings. High efficiency can be achieved in this class of SPM machine by making special efforts to suppress the eddy-current losses in the magnets [6-8], accompanied by efforts to minimize the iron losses in the rotor and stator cores. Considerable attention has traditionally been devoted to maximizing the full-load efficiency of traction machines at their rated operating points and along their maximum-power vs. speed envelopes for higher speeds [9,10]. For example, on-line control approaches have been presented for maximizing the full-load efficiency of PM synchronous machines, including the use of negative d-axis stator current to reduce the core losses [11,12]. However, another important performance specification for electric traction applications is the machine's efficiency at partial loads. Partial-load efficiency is particularly important ifmore » the target traction application requires long periods of cruising operation at light loads that are significantly lower than the maximum drive capabilities. While the design of the machine itself is clearly important, investigation has shown that this is a case where the choice of the control algorithm plays a critical role in determining the maximum partial-load efficiency that the machine actually achieves in the traction drive system. There is no evidence that this important topic has been addressed for this type of SPM machine by any other authors. This topic takes on even greater significance for fractional-slot concentrated-winding SPM machine designs. In particular, maximizing the torque/power density of this class of SPM machines typically leads to machine designs with high numbers of poles. The resulting high electrical frequencies can easily result in high stator core losses unless special care is taken during the machine design process. The purpose of this report is to discuss a modified vector control algorithm for a fractional-slot concentrated winding SPM machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. For purposes of this discussion, a 55 kW (peak) SPM machine designed to meet requirements established in the US FreedomCar program [13] is used as the basis for demonstrating the proposed technique. A combination of closed-form analysis [14] and finite element analysis (FEA) is used during this investigation. « less
Monitoring Activities Following The GroundingOf The MSC Napoli In Lyme Bay, UK, In 2007

On 18 January 2007, severe storms and huge waves battered the MSC Napoli outbound from Europe along the English Channel, seriously damaging its hull. Eighty km south of the UK coast, severe cracks developed in both sides of the hull and flooded the engine room. The crew abandoned ship and were airlifted to safety. The ship was taken in tow by two emergency towing vessels maintained on station by the UK and French governments and set off for Portland Harbour. Unfortunately the condition of the ship worsened and, amid fears that she may sink offshore, was beached 1 km off Branscombe Beach in Devon, within Lyme Bay. This area is part of Britain’s first World Heritage Site (the Jurassic Coast), and of high nature conservation importance. The vessel was carrying over 40,000 tonnes of cargo in 2,318 containers. Of these, 159 contained 1,684 tonnes of dangerous goods as classified by the IMO criteria. These included a wide variety of industrial and agricultural chemicals such as pesticides, fumigants, solvents and personal care products. As a component of the UK response, a monitoring programme was established, involving bodies such as Cefas, the Environment Agency, Natural England, the Plymouth Marine Laboratory, and the University of Plymouth, with overall co-ordination by Cefas. As well as one-off surveys, regular monitoring was undertaken of waters around the coast of the bay and of crabs and scallops collected during routine fishing activities in Lyme Bay, along with farmed mussels from Portland Harbour. Chemical analysis and toxicity testing of waters from the ship’s holds and engine room were also conducted routinely to monitor the risk from water being released to the bay. The overall impact of the incident was less than first feared.
Optimal Inventory Policy of Production Management: A Present Value Framework

The classical economic production quantity (EPQ) assumes that the replenishments are instantaneous. As a manager of a factory, there is a problem must be taken into consideration. If the establishment buys all of the raw materials at the beginning, the stock-holding cost for the raw materials should be counted into the relevant costs. So the main purpose of this paper will add the raw materials stock-holding cost to the EPQ model and take the time value of money into consideration. Therefore, we will calculate the present value and compare the difference between take and does not take the time value of money into consideration. From these procedures of calculating, we found some interesting results: 1) the present value of total stock-holding cost of raw materials plus products from the beginning to time t is the same as the stock-holding cost of classical economic order quantity (EOQ) model; 2) the present value of total relevant cost is independent of the production rate (if the production rate is greater than the demand rate); 3) the optimal cycle time of total relevant cost not taking the time value into consideration is the same the optimal cycle time of classical EOQ model; 4) the purchasing cost per unit time is irrelevant to time.
Challenges Experienced by Midwives Working in Rural Communities of the Bongo District in the Upper East Region of Ghana. A Qualitative Study

IntoductionGlobally, a total of 295 000 women lost their lives due pregnancy and childbirth in 2017, with sub-Saharan Africa and South Asia accounting for approximately 86% of all maternal deaths. Currently the Maternal Mortality Ratio (MMR) in Ghana is uncceptably high with about 308 deaths/100,000 live births in 2017 and most of these maternal deaths occur less in urban areas than in rural areas. As midwives play a vital role in maternity care and in the reduction of MMR, this study therefore sought to explore and describe challenges experienced by midwives working in rural communities in the Bongo District of the Upper East region of Ghana.MethodsA qualitative descriptive exploratory design was used to gain better insight into midwives’ experiences of working and providing women-centred midwifery care in rural areas of Ghana. A total of 30 midwives providing midwifery care in rural areas of the Upper East region of Ghana for at least three years were purposefully selected for this study. Data were collected using individual semi-structured interviews and analysed through qualitative content analysis. ResultsFive main themes emerged from the data analysis. These thematic areas included inadequate infrastructure (lack of bed and physical space), lack of logistics, shortage of midwifery staff, lack of motivation, and limited in-service training opportunities.ConclusionThe study concludes that although the rural midwives perform a multidisciplinary function in providing midwifery care in rural northern Ghana, they experience a myriad of challenges in providing midwifery care. There is the need for the Ghana Health Service and other stakeholders to motivate midwives working in rural areas through policy interventions such as rural incentive allowances, supportive supervision and in-service training opportunities for midwives in order to encourage them to accept posting to rural areas of Ghana to improve maternal and child health care.
A hybrid data compression approach for online backup service

With the popularity of Saas (Software as a service), backup service has becoming a hot topic of storage application. Due to the numerous backup users, how to reduce the massive data load is a key problem for system designer. Data compression provides a good solution. Traditional data compression application used to adopt a single method, which has limitations in some respects. For example data stream compression can only realize intra-file compression, de-duplication is used to eliminate inter-file redundant data, compression efficiency cannot meet the need of backup service software. This paper proposes a novel hybrid compression approach, which includes two levels: global compression and block compression. The former can eliminate redundant inter-file copies across different users, the latter adopts data stream compression technology to realize intra-file de-duplication. Several compressing algorithms were adopted to measure the compression ratio and CPU time. Adaptability using different algorithm in certain situation is also analyzed. The performance analysis shows that great improvement is made through the hybrid compression policy.
Optimization of Shrinkage in Plastic Injection Molding Process Using Statistical Methods and SA Algorithm

— Dimensional changes because of shrinkage is one of the most important problems in production of plastic part using injection molding. In this study, effect of injection molding parameters on the shrinkage in polypropylene (PP) and polystyrene (PS) has been investigated. The relationship between input and output of the process is investigated using regression analysis and ANOVA method. To do this, existing data is used. The selected input parameters are melting temperature, injection pressure, packing pressure and packing time. Effect of these parameters on the shrinkage of above mentioned materials is studied using mathematical modeling. For modeling the process, different types of regression equations including linear polynomial, Quadratic polynomial and logarithmic function, are used to interpolate experiment data. Next, using step backward elimination and 95% confidence level, insignificant parameters are eliminated from model. To check validity of the PP model, correlation coefficient of each model is calculated and the best model is selected. The same procedure is repeated for the PS model. Finally, optimum levels of the input parameters that minimize shrinkage, for both materials are determined. Simulated Annealing (SA) algorithm is applied on the developed mathematical models. The optimization results show that the proposed models and algorithm are effective in solving the mentioned problems.
Parameter Study of Opposite Tape-Spring Flexure Hinge

Parameter study for the qusai-static folding and deployment of opposite tape-spring flexure (OTSF) hinges is presented. The full factorial method is employed to design of experiments, and the qusai-static folding and deployment nonlinear analysis is obtained by ABAQUS/Explicit solver. Parametric studies show that both the section radius and the central angle have significant effects to the peak moment of quasi-static folding and deployment of the OTSF hinges. However, the maximum Mises stress in complete folding configuration is more sensitive to the central angle than the section radius.
The application of the diversity in mobile free-space optical communication

Traditional free-space optical (FSO) communications use a single transmitting antenna (laser/VCSEL/LED) and a receiving antenna (a photo-detector) for single channel communication between two nodes. In this paper we study two transmitting antenna one receiving antenna M-FSO (mobile FSO) communication system. In the process of single transmitting antenna moving, the optical beam broadens to make receive power smaller with the divergence angle larger and the power is difficult to be detected when long-distance communication. When short-distance communication, the divergence angle is so small that it makes a narrow beam which is hard to be aimed at receive aperture, even more serious when the beam is out of target caused by vibration. We take advantage of space diversity technology to reduce BER caused by atmospheric turbulence and mobile vibration. Through the multi-transmitter, the best choice of multi-divergence angle reduces BER, thus the receiver accurately recovers information.
Theoretical and experimental characterization of thermal effects in doped fibers

Nonradiative decay mechanisms in doped fibers introduce heat into the fiber core and often decrease the upper state lifetime of a dopant. This can be detrimental to doped-fiber lasers, amplifiers, and in some cases all-optical switches. In this paper we report theoretical and experimental studies of thermal effects in doped fibers, with particular emphasis on their impact on all-optical nonlinear switches using resonant nonlinearities. We observe significant thermal effects in transition metal-doped silica fibers. We determine that sub-microsecond(s) switching using a resonant nonlinear effect in a conventional switch architecture requires dopant oscillator strengths of 3.6 10-3 or greater when nonradiative processes are the predominant decay mechanism.
Approximate evaluation of the wave propagation parameters of MF TL communication systems for mine tunnels using image theory

Mine tunnel communications are migrating to wireless; however, medium frequency (MF) communications based on conductor-to-wall transmission line (TL) structures still exist and can be used as emergency or backup systems. This research, addressing MF TL communication systems, is aimed at the finding of simple approximated expressions of the wave propagation parameters characterizing the transmission properties of such systems: attenuation, phase velocity, and characteristic impedance. Bearing in mind the variety of tunnels’ geometries and the lack of rigorous information about the surrounding soil electromagnetic properties, it turns clear that general accurate solutions of the problem are out of reach in a general formulation. In this work, a tunnel model with an equivalent circular cross section and a homogeneous soil with average conductivity is adopted and analyzed. The novelty of the analysis is its intrinsic simplicity due to the employment of image theories, which are applied not only to obtain the .