Flexible Placement Research Articles

Position Invariance for Wearables: Interchangeability and Single-Unit Usage via Machine Learning

We propose a new methodology to attain invariance to the positioning of body-worn motion-sensor units for recognizing everyday and sports activities. We first consider random interchangeability of the sensor units so that the user does not need to distinguish between them before wearing. To this end, we propose to use the compact singular value decomposition (SVD) that significantly reduces the accuracy degradation caused by random interchanging of the units. Second, we employ three variants of a generalized classifier that requires wearing only a single sensor unit on any one of the body parts to classify the activities. We combine both approaches with our previously developed methods to achieve invariance to both position and orientation, which ultimately allows the user significant flexibility in sensor-unit placement (position and orientation). We assess the performance of our proposed approach on a publicly available activity data set recorded by body-worn motion-sensor units. The experimental results suggest that there is a tolerable reduction in accuracy, which is justified by the significant flexibility and convenience offered to users when placing the units.

Experimental investigation of optimal location of flow straightener from the aspects of power output and pressure drop characteristics of a thermoelectric generator

This study addresses the combined effects of the location and porosity of a flow straightener on the waste heat recovery performance of a thermoelectric generator (TEG). An exhaust gas channel was built for the flexible placement of a flow straightener with varying porosity in the range of 0.121–0.516 at five different locations. Customized thermoelectric modules were placed between the exhaust gas channel and two coolant channels for waste heat recovery. A diesel engine releases the exhaust gas flow into the exhaust gas channel of the TEG placed in the middle of the tail pipe. Experimental results showed that a TEG design in which a flow straightener is positioned near the inlet of the TEG needs to be avoided because of a low power output to pressure loss ratio. The net power output, energy conversion efficiency, and pressure drop characteristics were enhanced as the location of flow straightener moved rearward of the TEG. A friction factor correlation was also proposed for predicting pressure drop characteristics of TEGs equipped with a flow straightener to improve their practicality in industry and engineering fields.

Mouth magnetoencephalography: A unique perspective on the human hippocampus

Traditional magnetoencephalographic (MEG) brain imaging scanners consist of a rigid sensor array surrounding the head; this means that they are maximally sensitive to superficial brain structures. New technology based on optical pumping means that we can now consider more flexible and creative sensor placement. Here we explored the magnetic fields generated by a model of the human hippocampus not only across scalp but also at the roof of the mouth. We found that simulated hippocampal sources gave rise to dipolar field patterns with one scalp surface field extremum at the temporal lobe and a corresponding maximum or minimum at the roof of the mouth. We then constructed a fitted dental mould to accommodate an Optically Pumped Magnetometer (OPM). We collected data using a previously validated hippocampal-dependant task to test the empirical utility of a mouth-based sensor, with an accompanying array of left and right temporal lobe OPMs. We found that the mouth sensor showed the greatest task-related theta power change. We found that this sensor had a mild effect on the reconstructed power in the hippocampus (~10% change) but that coherence images between the mouth sensor and reconstructed source images showed a global maximum in the right hippocampus. We conclude that augmenting a scalp-based MEG array with sensors in the mouth shows unique promise for both basic scientists and clinicians interested in interrogating the hippocampus.

Analysis and Optimization of Fog Radio Access Networks With Hybrid Caching: Delay and Energy Efficiency

In this article, delay and energy efficiency (EE) are investigated in fog radio access networks (F-RANs) with hybrid caching. With multiple caching and transmission strategies, hybrid caching offers great flexibility for file placement and file fetching. By using tools from stochastic geometry, we firstly derive tractable expressions of delay for coded cached, non-partitioned cached and uncached files. Then, we derive tractable expressions of EE by jointly considering power consumed in circuits, transmissions and fronthaul links. To balance delay and EE, the corresponding multi-objective optimization problem is formulated to obtain the optimal hybrid caching strategy. Furthermore, considering the NP-hard complexity of the problem, we first theoretically analyze the optimal structure of the caching result. Then, we convert the original problem into a classification problem. We further propose a gradual-replacement greedy algorithm to obtain a near optimal hybrid caching strategy, which ensures high accuracy with low complexity. Numerical results show a significant performance gain of the proposed near optimal hybrid caching strategy over baselines and flexibility in delay-sensitive and EE-sensitive scenarios.

TRAVERSAL: A Fast and Adaptive Graph-Based Placement and Routing for CGRAs

Coarse grain reconfigurable architectures (CGRAs) are an emerging hybrid computational architecture that has the parallel customization benefits of low-level logic devices, such as FPGAs and ASICs, while the relative coarseness of these architectures makes CGRAs easier to design for, which is more similar to the traditional processor. In the process of mapping designs to CGRAs, flexible, fast, and adaptive placement and routing (P&R) is fundamental in order to implement efficient run-time reconfigurable frameworks. It is well-known that P&R is an NP-complete problem, and thus, solutions rely on heuristics to achieve quality results with acceptable execution times. CGRA P&R has different constraints compared to traditional VLSI P&R, e.g., path latency balancing and modulo scheduling of loops. In this work, we propose a graph-based P&R approach that uses graph traversals to map designs to CGRAs. Additionally, we parallelize our approach with a graph-based greedy heuristic that executes on a GPU. We compare our proposed P&R approach with the CGRA-ME framework, which implements simulated annealing and integer linear programming placement algorithms. Our results show that this new approach can generate optimal mappings and improve the execution run-time up to several orders of magnitude. Furthermore, considering spatial mapping at the millisecond scale, our GPU approach is one order of magnitude faster compared to the state-of-the-art tool VPR.

Оптимізація паралельних алгоритмів з використанням моделі акторів

Introduced methods and instrumentation tools for actor model applied to block recursive algorithms optimization. Created formal model of distribution and coordination of the tasks in computation cluster as asynchronous reactive processes with message-passing represented with an actor model and choreography of actors. Created declarative definitions of algorithms which compiles to the system of actors. Proposed scheme of data placement in a cluster using prioritization of block-recursive operations to reduce idling time, data movement, with increased parallelism in situation of high-speed processors and reduced network bandwidth. Implemented adaptive adjustment of the data placement in a cluster at run time to account for current cluster load. Created autotuning of the actor placement in а cluster which uses statistics of previous runs for optimization. Usage of choreography of actors allows to remove central coordinating element and to avoid hard dependencies between cluster nodes, which provides flexible data placement, improves fault tolerance with no single point of failure and allows to use self-healing.

Information society: socio-hygienic aspects of the transformation of employment and working environment

Introduction. The current historical period is characterized by significant transformations in all spheres of life activity. The reasons for the changes are the development of information technologies and globalization processes. In the information (post-industrial) society, transformations are associated with the introduction of the principles of flexibility in job placement and labor organization. The transition to flexible forms of employment appears as a risk factor for the deterioration of working conditions and the reduction of workers’ security. “Social pollution” of the production environment is spreading. These include management methods that harm the well-being of workers.The aim of the study is the evaluation of the influence of flexibilities of employment and labor relations on the deterioration of working conditions as a risk factor for the well-being of workers.Material and methods. The study object in the article is flexibility as a socio-psychological and organizational-economic phenomenon. A comparative analysis of the views of various authors and their theoretical generalization.Results. A modern understanding of the information society as a society of network structures based on innovation and decentralization, as well as employment on adaptability to market conditions is presented. The introduction of the flexibility of employment means a departure from the standard model of labor relations. The negative consequences of labor flexibility for workers are given: instability, compulsion, unsteadiness, and lack of guarantees. Employment unsteadiness occurs both in the informal and formal sectors of the economy. The statistics cited indicate a trend towards an increase in the proportion of workers included in unsustainable and precarious employment. The influence of “social pollution” of the intra-organizational environment in the form of adverse management decisions introducing instability and unreliability in working conditions is considered. Their consequence is a violation of the social and psychological well-being and somatic health of workers. Conclusion. The more employment differs from the standard, the higher its instability, and lack of guarantees for the worker, the higher the risks of deterioration of working conditions, health, and job loss. There is a connection between the instability of employment, psychological well-being, and health.

GECOM: GREEN COMMUNICATION CONCEPTS FOR ENERGY EFFICIENCY IN WIRELESS MULTIMEDIA SENSOR NETWORK

Wireless multimedia sensor network (WMSN) is one of broad wide application for developing a smart city. Each node in the WMSN has some primary components: sensor, microcontroller, wireless radio, and battery. The components of WMSN are used for sensing, computing, communicating between nodes, and flexibility of placement. However, the WMSN technology has some weakness, i.e. enormous power consumption when sending a media with a large size such as image, audio, and video files. Research had been conducted to reduce power consumption, such as file compression or power consumption management, in the process of sending data. We propose Green Communication (GeCom), which combines power control management and file compression methods to reduce the energy consumption. The power control management method controls data transmission. If the current data has high similarity with the previous one, then the data will not be sent. The compression method compresses massive data such as images before sending the data. We used the low energy image compression algorithm algorithm to compress the data for its ability to maintain the quality of images while producing a significant compression ratio. This method successfully reduced energy usage by 2% to 17% for each data.

Clinical results of a short stem with flat tapered wedge design in primary total hip arthroplasty for hip dysplasia in Asians.

Cementless femoral reconstruction is challenging in hip dysplasia due to deformity of the proximal femur causing insufficient stem fixation and/or inadequate neck anteversion. Strategies to address these problems include the use of a modular stem or a distal fixation stem, but both stems have some characteristic disadvantages. We studied the postoperative clinical outcomes in primary total hip arthroplasty in 257 hips using the flat tapered wedge short femoral stem for hip dysplasia in an Asian population (postoperative follow-up period: 2 years to 6 years and 11 months; mean 4 years and 5 months). We took advantage of the characteristic of high flexibility in stem placement because of its low volume, positioning it while performing some varus/valgus and rotational alignment adjustments. Favorable clinical functional outcomes were obtained, including the radiographic outcome of biological fixation achieved in all stems. Regarding complications, there was no case of split fracture of the femoral calcar region during stem insertion, and the rate of postoperative dislocation was also low at 0.4% (1 case). In the pre- and postoperative computed tomography measurements, the variability in stem anteversion postoperatively was significantly reduced compared to preoperative anatomical anteversion. This flat-shaped short low-volume stem likely has high flexibility in positioning in cases of hip dysplasia and can be easily positioned to avoid fractures while still achieving secure fixation.

An Acoustic Vehicle Detector and Classifier Using a Reconfigurable Analog/Mixed-Signal Platform

The wireless sensor nodes used in a growing number of remote sensing applications are deployed in inaccessible locations or are subjected to severe energy constraints. Audio-based sensing offers flexibility in node placement and is popular in low-power schemes. Thus, in this paper, a node architecture with low power consumption and in-the-field reconfigurability is evaluated in the context of an acoustic vehicle detection and classification (hereafter “AVDC”) scenario. The proposed architecture utilizes an always-on field-programmable analog array (FPAA) as a low-power event detector to selectively wake a microcontroller unit (MCU) when a significant event is detected. When awoken, the MCU verifies the vehicle class asserted by the FPAA and transmits the relevant information. The AVDC system is trained by solving a classification problem using a lexicographic, nonlinear programming algorithm. On a testing dataset comprising of data from ten cars, ten trucks, and 40 s of wind noise, the AVDC system has a detection accuracy of 100%, a classification accuracy of 95%, and no false alarms. The mean power draw of the FPAA is 43 μ W and the mean power consumption of the MCU and radio during its validation and wireless transmission process is 40.9 mW. Overall, this paper demonstrates that the utilization of an FPAA-based signal preprocessor can greatly improve the flexibility and power consumption of wireless sensor nodes.

Flexible endoscopic placement of double lumen tube as a primary technique. Time-saving or consuming?

Flexible endoscopic placement of double lumen tube as a primary technique. Time-saving or consuming?

Evaluation of Space Time Beamforming Algorithm to Realize Maintenance-Free IoT Sensors With Wireless Power Transfer System in 5.7-GHz Band

Smart factories can be realized by effective and flexible placement of IoT sensors in all equipment. Even though many energy-efficient solutions are aimed at enhancing IoT sensor lifetimes, additional maintenance is required to replace batteries after a stipulated amount of time. To overcome this burden and realize maintenance-free IoT sensors, we evaluate a space-time beamforming (STBF) algorithm based on microwave power transfer in a 5.7-GHz band and compare the required transmit power with typical beam-splitting algorithms, namely Max-Sum and Max-Min. We also experimentally evaluate the usability of STBF and verify the required transmit power to realize maintenance-free IoT sensors.

An experimental analysis of deepest bottom-left-fill packing methods for additive manufacturing

The adoption of Additive Manufacturing (AM) technology requires the efficient utilisation of the avail- able build volumes to minimise production times and costs. Three-dimensional algorithms, particularly the Deepest Bottom-Left-Fill (DBLF) heuristic, have been extensively used to tackle the problem of packing arbitrary 3D geometries within the AM sector. A particularly common method applied to more realistic packing problems is the combination of DBLF and metaheuristics such as Genetic Algorithms (GAs). Through a series of experiments, this paper experimentally investigates the practical aspects, and comparative performance of different DBLF based methods including a brute force algorithm and GA combined with DBLF for AM build volume packing. The insights into the relationship between algorithm efficiency (in terms of volume utilisation), simulation runtime, and practical requirements, in particular geometry rotation constraints are investigated. In addition to providing an increased comprehension of the practical aspects of applying DBLF algorithms in the AM context, this study confirms the limita- tions of traditional DBLF and the requirements for more flexible and intelligent placement strategies while experimentally demonstrating that higher degrees of freedom for part rotation contribute to small improvements in volume density. The resulting additional computational effort discourages this strategy, however.

Efficient quasiparticle traps with low dissipation through gap engineering

Quasiparticles represent an intrinsic source of perturbation for superconducting qubits, leading to both dissipation of the qubit energy and dephasing. Recently, it has been shown that normal-metal traps may efficiently reduce the quasiparticle population and improve the qubit lifetime, provided the trap surpasses a certain characteristic size. Moreover, while the trap itself introduces new relaxation mechanisms, they are not expected to harm state-of-the-art transmon qubits under the condition that the traps are not placed too close to extremal positions where electric fields are high. Here, we study a different type of trap, realized through gap engineering. We find that gap-engineered traps relax the remaining constraints imposed on normal metal traps. Firstly, the characteristic trap size, above which the trap is efficient, is reduced with respect to normal metal traps, such that here, strong traps are possible in smaller devices. Secondly, the losses caused by the trap are now greatly reduced, providing more flexibility in trap placement. The latter point is of particular importance, since for efficient protection from quasiparticles, the traps ideally should be placed close to the active parts of the qubit device, where electric fields are typically high.

Optimizing robot motion for robotic ultrasound-guided radiation therapy

An important aspect of robotic radiation therapy is active compensation of target motion. Recently, ultrasound has been proposed to obtain real-time volumetric images of abdominal organ motion. One approach to realize flexible probe placement throughout the treatment fraction is based on a robotic arm holding the ultrasound probe. However, the probe and the robot holding it may obstruct some of the beams with a potentially adverse effect on the plan quality. This can be mitigated by using a kinematically redundant robot, which allows maintaining a steady pose of the ultrasound probe while moving its elbow in order to minimize beam blocking. Ultimately, the motion of both the beam source carrying and the ultrasound probe holding robot contributes to the overall treatment time, i.e. beam delivery and robot motion. We propose an approach to optimize the motion and coordination of both robots based on a generalized traveling salesman problem. Furthermore, we study an application of the model to a prostate treatment scenario. Because the underlying optimization problem is hard, we compare results from a state-of-the-art heuristic solver and an approximation scheme with low computational effort. Our results show that integration of the robot holding the ultrasound probe is feasible with acceptable overhead in overall treatment time. For clinically realistic velocities of the robots, the overhead is less than 4% which is a small cost for the added benefit of continuous, volumetric, and non-ionizing tracking of organ motion over periodic x-ray-based tracking.

Patient-Specific Energy Verify Using the Multilayer Acrylic Disk Detector for Proton Pencil Beam Scanning

The total dose distribution of the proton pencil beam scanning (PBS) is constructed by individually delivered Bragg peaks and its uniformity depends directly on the accuracy of the delivery (i.e., the beam energy and the spot location). This study is the major reason for verifying the layer-by-layer energy along the scan path of PBS and was newly constructed the acrylic-disk radiation sensor (ADRS) of 20-layers to compare efficiency with the commercial multilayer ionization chamber (MLIC). We analyzed the properties of a multilayer ADRS to evaluate that it is suitable for the new QA system, and to compare the measured patient-specific energy with those predicted by the treatment planning system (TPS). The final goal of this study is to suggest optimized systems and methods for quickly and accurately carry out existing QA processes in PBS proton therapy. The measurements were obtained from a clinical proton pencil beams (IBA Proton Therapy System-Proteus 235). The multilayer ADRS is a series of transmitter disk (BC-800) with 150 mm diameter surrounded by thin optical fiber (PGS-CD1001-13-E). This disk is an ultraviolet-transparent methyl methacrylate polymer and shows water equivalency (mass density of 1.19 gcm-3) and has many other advantages; easy processing, remote sensing, and no interference from electromagnetic fields. It is now improved the efficiency of the measurement by arranging the ADRS of 20-layers and fabricating black plastic cases that allow for flexibility in placement of the solid slabs phantom, including in the extra room. It is also designed with a 1 mm thick disk which is as thin as can be reliably manufactured for verifying the layer-by-layer energy. The new is a significant step forward towards high spatial resolution compared to the previous version, which was made with a thickness of 2 mm. We investigated the feasibility of the multilayer ADRS to verify the layer-by-layer energy along the scan path for patients treated with PBS in three different sites (prostate, head & neck, and lung). The inaccuracy effect of the beam energy creates an uneven distance between adjacent layers in depth and thus cause ripples in depth, particularly at the shallower part where the Bragg peak is distinctively narrow. To evaluate the patient-specific energy, results calculated by the TPS and measured by the multilayer ADRS showed significant differences in the integrated energy of each layer depending on the treatment site. Therefore, the patient-specific energy calculated by the TPS must be compared and verified by the measured value prior to treatment. In this study, we believe that the multilayer ADRS has considerable potential to verify the energy for PBS proton therapy system.

Mobile Edge Provision with Flexible Deployment

The Mobile Edge Network (MEN) has emerged as the basic infrastructure to support fifth-generation networks, mobile edge computing and fog computing. The characteristics of mobility must be addressed to guarantee the quality of service in MENs. As one of the critical problems in MENs, flexible deployment plays a part in exploiting edge networks. Despite the abundance of recently proposed strategies, most concentrate on the change in user demands and inevitably ignore the influence for the user mobility, which is common in future networks. We propose Provision for Mobile Edge Computing (PMEC), a prototype that takes advantage of storage devices with flexible placement. In PMEC, we accommodate various considerations and select different storage devices to cache, deploying the cache with the relationship of a two-tiered structure in the MEN. Thus, we construct a flexible overlay network with the objective of minimizing the cost in a two-tiered edge network. Based on the analysis of the problem, we solve the two-tiered placement from bottom to top using the dynamic minimal spanning tree (MST) algorithm and design two algorithms for each tier including the basic algorithm and the improved algorithms. The simulation is conducted on realistic data to demonstrate the performance of our algorithms.

Focus on test, measurement, and analytical equipment

Focus on test, measurement, and analytical equipment

Flexible replica placement for enhancing the availability in edge computing environment

As edge devices that make up the Internet become more powerful, these devices in edge computing environment will even perform better in improving the computing and storage capabilities of system. In this paper, to enhancing data availability and improve cloud storage performance in edge computing environment, an adaptive replica placement strategy in edge computing environment is proposed to study the relationship among user access characteristics, the number of replicas, and the replicas location. To deal with the volatility of user access, the strategy in this paper takes data block as the data unit and the dynamic replica creation algorithm (DRC-GM) is proposed. DRC-GM uses the relationship between access frequency of data blocks and the number of replicas to dynamically adjust the number of replicas to ensure data availability requirements. To find the optimal location for replica distributed placement, in this paper, the replica placement algorithm (RP-FNSG) is proposed. And replica number, node performance and replica consistency are considered. Experiment results show that DRC-GM and RP-FNSG algorithms in edge computing environment can greatly improve system performance in terms of better prediction accuracy, shorter access response, higher effective network and storage space usage, which enhancing the data availability.

A Flexible Subcarrier Multiplexing System With Analog Transport and Digital Processing for 5G (and Beyond) Fronthaul

A flexible subcarrier multiplexing system combining analog transport with digital domain processing is presented. By making use of bandpass sampling and applying a systematic mapping of signals into available Nyquist zones, the multiplexing system is able to present multiple signals at the same intermediate frequency at the remote site. This simplifies the processing required for multiple antenna systems. We further propose the use of track-and-hold amplifiers at the remote site. These elements are used to extend the mapping to a mapping hierarchy, offering flexibility in frequency placement of signals and relaxation of analog-to-digital converter bandwidth and sampling rate constraints. The system allows the transport of different numerologies in a number of next generation radio access network scenarios. Experimental results for large signal multiplexes with both generic and 5th-generation mobile numerologies show error-vector magnitude performance well within specifications, validating the proposed system. Simulation results from a system model matched to these experimental results provide performance predictions for larger signal multiplexes and larger bandwidths.