Synchronization Procedure Research Articles

RESEARCH OF THE PROCEDURE OF INITIAL ACCESS TO THE FIFTH GENERATION COMMUNICATION NETWORK

Traditional mobile networks have bandwidth and infrastructure limitations. Each base station has a limited number of users and data capacity. 5G technology uses advanced technologies, such as massive MIMO and beamforming, to increase data rates and spectrum efficiency. These features, and the large number of small cells, allow many 5G users to receive low latency and high traffic without overloading the base station. Small cells work the same way as regular cells, but use new technology and millimetre waves (5G New Radio). Low-power base stations can be easily deployed. Cell search is a procedure by which the user equipment (UE) obtains time and frequency synchronization with the base station and decodes the cell ID of the mobile device. System information is broadcast information that is periodically transmitted by the base station on the downlink. This is very important information for the mobile device (UE) needed to connect to the base station (gNB). The UE reads system information to determine the location of mobile devices when turned on, to select and re-select a cell. System information provides the following information: system frame number, system bandwidth, PLMN, mobile subscriber selection and redial thresholds, etc., required to access the network. Physical Cell ID (PCI) is used to distinguish mobile devices in the network radio communication. PLMN (Public land Mobile Network) – mobile network service area. Is a set of all mobile devices of one cellular network operator. The UE scans the bandwidth in the sync raster. The synchronization raster indicates the frequency positions of the synchronization unit that can be used by the UE to detect the system when there is no explicit indication of the position of the synchronization unit. In the next step, the UE decodes the primary and secondary synchronization signals to obtain the Physical Cell ID (PCI) and the DMRS PBCH. The base station transmits SSB packets that contain one SSB per beam. The beam direction changes for each SSB transmission. The following steps are performed to complete the synchronization procedure. The UE selects the preferred beam and decodes the PBCH MIB information, such as SFN, SSB index, raster offset, default DL numerology, RMSI configuration, DM-RS location, and cell prohibition information. If the cell is not locked, the UE attempts to decode the physical downlink control channels (PDCCH) to obtain the frequency location of the PDSCH resources. A study of the model of restoring the synchronization of symbols and frames in the QPSK system, caused by a variable synchronization error. A study of the formation of the radio channel at the physical level.

Meta-Analysis for Comparison between Antireflux Surgery With or Without Endoscopic Management of Barrett's Esophagus

Abstract Background: In patients with BE, anti-reflux surgery aims to sustainable control reflux symptoms and heal reflux induced esophageal mucosal inflammation and prevent progression of BE to adenocarcinoma. Endoscopic resection of visible lesions if any, followed by ablation of the rest of the BE epithelium is the current standard of care for management of BE with confirmed dysplasia. Although the current literature describes multiple endoscopic and anti-reflux techniques for the management of BE, there is no published evidence on the efficacy of anti-reflux surgery followed by endoscopic man-agement on the outcomes of BE. Aim of Study: The objective of this study was to compare between anti-reflux surgery with or without endoscopic man-agement of BE. Patients and Methods: In the present study, we searched Medline via PubMed, SCOPUS, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar. The search retrieved 2089 unique records. We then retained 57 potentially eligible records for full-texts screening. Finally, 6 studies were included. Results: In the present systematic review and meta-analysis, five studies reported the rates of recurrence. The overall effect estimates showed the rate of recurrence was 5.7% (95% CI 1.2-10.2%). In the present systematic review and meta-analysis, five studies reported the overall complica-tions rate. The overall effect estimates showed the overall complications rate was 7.3% (95% CI 4.1-10.6%), mainly stricture and perforation. Conclusion: Endoscopic procedures after anti-reflux surgery is a safe modality, with high rate of success in complete eradication of BE in symptomatic GERD patients, especially those with severe anatomical impairment in distal esophageal segment. As a concurrent procedure, endoscopic procedures may be beneficial in the terms of reducing the early recurrence rates, which seems to be important issue during the manage-ment of BE. By doing synchronous endoscopic procedures and fundoplication, one might observe a true anatomy of esophagogastric junction in its entirety and might be able to truly observe the distal extent of columnar esophagus.

Cyclostationary Crosstalk Cancelation in High-Speed Transmission Lines

The theoretical and experimental evaluation of the cyclostationary random data transferring process corrupted by the individually and jointly cyclostationary crosstalk interference is presented. The interference and the message signals were measured by the real time digital oscilloscope. Autocorrelation functions were evaluated by synchronous cyclic averaging procedure. The analyzed periodic two-dimensional impulse response of the time-varying filter allows to obtain the output random process with the same cyclic frequency at the output of the filter by separation of orthogonal stationary waveforms constituting the input cyclostationary random process (CSRP). The filtering of the measured random process was implemented by the cyclic Wiener filter. The evaluation of the two-dimensional autocorrelation function and eye diagrams at the output of the cyclic Wiener filter showed significant reduction of the independent interference components in the estimated message signal.

The fast multi-frame X-ray diffraction detector at the Dynamic Compression Sector.

A multi-frame, X-ray diffraction (XRD) detector system has been developed for use in time-resolved XRD measurements during single-event experiments at the Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS). The system is capable of collecting four sequential XRD patterns separated by 153 ns, the period of the APS storage ring in the 24-bunch mode. This capability allows an examination of the temporal evolution of material dynamics in single-event experiments, such as plate impact experiments, explosive detonations, and split-Hopkinson pressure bar experiments. This system is available for all user experiments at the DCS. Here, the system description and measured performance parameters (detective quantum efficiency, spatial and temporal resolution, and dynamic range) are presented along with procedures for synchronization and image post-processing.

Phase shift control and controller area network assisted proportional resonant control for grid integration of single phase voltage source inverters

Grid integration of inverters using renewable sources of energy is essential for providing a secure and clean source of power supply. Many techniques developed so far control the grid current to realize the regulation of power flow to the power grid. However, implementation of communication assisted synchronization methods for single-phase full-bridge inverters is not found to be discussed in the literature. The focus of this research is to conceptualize, simulate, and implement two control techniques, namely Phase Shift Control (PSC) and Controller Area Network Assisted Proportional Resonant Control (CANAPRC) for single-phase inverters. In the PSC method, the inverter injects the desired real power into the grid by controlling the phase angle between converter and grid voltages. A low complexity synchronization procedure was adopted using single-phase PLL to generate a reference voltage signal using the PSC method. In contrast, the CANAPRC method outputs a current reference created by the resonant controller using a communication network. The inverter can pump the required real and reactive power to the grid with reduced harmonics, enhanced power-sharing and transient stability using the two strategies. Simulations in MATLAB R2016a analyze the two models out effectively. Prototype models validate the proposed control strategies.

Grid synchronization of variable speed pump-turbine units in turbine mode

The S-shaped characteristics of the pump-turbine may cause instability and thus leads to difficulties in grid synchronization. This paper develops a complete model for a pumped storage power plant and studies the start-up and grid synchronization procedure of two 300 MW variable speed units at no load in turbine mode. Based on the grid-voltage-oriented vector control method, the stator voltage of the doubly-fed induction machine is controlled to meet the grid connection requirements. Compared with the fixed speed units, the simulation results show that for a pump-turbine with typical S-shaped characteristics, the fixed speed unit cannot meet the grid connection requirements due to the unstable unit speed. Whereas, the variable speed unit can quickly reach synchronization with the grid voltage. For a pump-turbine without typical S-shaped characteristics, the synchronous unit can meet the grid connection requirements, but it takes a longer time and the stator voltage is not stable enough, while the variable speed unit is 11 times faster and more stable. The effects of PI parameters on the synchronization process of a variable speed unit are also studied. The results show that with suitable PI control parameters, the synchronization process can be accelerated without large overshoot of the rotor power.

SYNCHRONOUS CAROTID ENDATERECTOMY AND CORONARY ARTERY BYPASS GRAFTING VERSUS STAGED PROCEDURE IN PATIENTS WITH SEVERE CAROTID AND CORONARY ARTERY DISEASE

Background Atherosclerosis is a pathological process involving blood vessels all over the body in varying intensity. Occurrence of significant carotid artery disease in patients requiring coronary artery bypass grafting (CABG) results in a dilemma regarding the best surgical strategy for addressing both. Our objective was to compare the efficacy of synchronous carotid endarterectomy(CEA) and CABG with staged CEA followed by CABG. Methods During a four year period, from April 2013 to March 2017, 42 patients underwent CEA with CABG. Of these, 20 patients underwent synchronous procedure (group 1), and 22 underwent staged procedures (group 2) within 30 days apart. Results 42 patients underwent CEA with CABG either in synchronous or staged fashion. In synchronous group, 2 patients (10%) had stroke, 3 patients (15%) had reversible ischemic neurological deficit and 4 patients (20%) had convulsions. In the staged group, one patient (4.5%) required re-exploration for bleeding, 1 patient (4.5%) had stroke and 1 patient (4.5%) had convulsions. The result was found to be statistically significant on comparing group 1 with group 2. Conclusion Synchronous and staged procedures have their own merits and demerits. Patients with critically stenosed coronary and carotid artery lesions with accompanying severe comorbidities should preferably undergo synchronous procedures with CEA followed by CABG and staged procedures should be reserved for patients with chronic stable angina with lesser comorbidities.

Asymmetrical pythagorean-hodograph (PH) spline-based C3 continuous corner smoothing algorithm for five-axis tool paths with short segments

• A real-time C 3 continuous corner smoothing algorithm is proposed for five-axis short linear segments. • The proposed method can achieve lower curvature based on asymmetrical PH splines. • Smoothing errors around the corners are bounded under given constraints. • The arc-length can be analytically calculated to achieve real-time interpolation. • Experiments verify that much lower curvature and higher machining efficiency can be realized. Local corner smoothing is widely used for the G01 motion commands to achieve the motion continuity of transition corners. Most splines constructed by the existing local corner smoothing methods oriented for five-axis machining mainly must be connected by linear segments. However, with respect to the five axis machining of the corners with short line segments, these kinds of methods need that both ends of the constructed splines usually must be shrunk with the same proportion to avoid the overlapping of adjacent splines. This will lead to relatively large curvatures of the obtained trajectories together with relatively low machining efficiency. This article proposes a new real-time corner smoothing algorithm for five-axis machine tools by constructing the C 3 continuous asymmetrical PH splines. The typical characteristic lies in that the control points related to the two ends of the PH spline can be independently adjusted through reasonably introducing two more adjustable variables, which are realized by analytically calculating and then adding two additional control points into the corresponding control polygon. As a result, the PH spline poses the property of the asymmetry about the angular bisector. Based on this, the short linear commands of tool tip and tool orientation can be smoothed only through inserting different lengths of asymmetrical PH splines that can be connected directly. The motion variance of the smoothed tool orientation related to the tool tip displacement is analytically proved to be C 3 continuous, and thus, the synchronization between tool tip and tool orientation is guaranteed. The outstanding advantage of the algorithm for short line segments is twofold. The first is that the performance of the drives can be more fully utilized to reduce cycle time since the curvature around corners are reduced by adopting the asymmetrical profile, and the second is that the synchronization procedure is greatly simplified since the algorithm eliminates the requirement to convert the intermediate line segments into a spline between the adjacent connected PH splines. Both simulation and the experimental results demonstrate that the proposed algorithm can realize a higher machining efficiency.

RAMCI: a novel asynchronous memory copying mechanism based on I/OAT

Memory copying is one of the most common operations in modern software. Usually, the operation reflects a synchronous (sync) CPU procedure of memory copying, incurring overheads such as cache pollution and CPU stalling, especially in the scenario of bulk copying with large data. To improve this issue, some works based on I/OAT, which is a dedicated and popular hardware copying engine on Intel platform, is proposed but still exists several problems: (1) lacking atomic allocation/revocation at the granularity of I/OAT channel; (2) deficiency of interrupt support and (3) complicated programming interfaces. We propose RAMCI, an asynchronous (async) memory copying mechanism based on Intel I/OAT engine, not only improves the sync overheads, but also overcomes the above three issues through (1) a lock mechanism by using low-level CAS instruction; (2) a lightweight interrupt mechanism for the completion of memory copying, instead of using the polling pattern which consuming large CPU resource and (3) a group of well-defined and abstract interfaces, allowing the programmers to utilize the underlying free I/OAT channels transparently. To support the interfaces, a novel scheduler of the I/OAT channels is introduced. It splits the source copying data into several pieces, and each of them can be allocated with a dedicated I/OAT channel intelligently to transfer the data with parallelism. We evaluate RAMCI and compare it with other memory copying mechanisms in four NUMA scenarios. The experimental results show that RAMCI improves memory copying performance up to 4.68 $$\times $$ while achieving almost full ability of parallel computing.

Synchronization Techniques in “Device to Device- and Vehicle to Vehicle-Enabled” Cellular Networks: A survey

Device-to-Device (D2D) communication is introduced for cellular networks allowing User Equipments (UEs) to communicate directly in close physical proximity. In traditional cellular networks, time synchronization is performed by the network infrastructure equipment to address the challenges of coordinating independent clocks and tasks of UEs to communicate with each other. These challenges are more critical in D2D as the network has no central point to coordinate UEs. The aim of this paper is twofold: (i) reviewing synchronization standards and techniques for D2D-enabled cellular networks and (ii) discussing different scenarios and contemporary cellular network generations. We review the main signals, channels, and entities used by D2D-enabled cellular networks for synchronization procedures in different scenarios. Moreover, we focus on the synchronization in Vehicle-to-Vehicle (V2V) and Vehicle-to-Everything (V2X). Finally, we conduct a literature study on effective proposed synchronization techniques in D2D and vehicular communications to highlight recent advances and provide future directions.

Bilateral foam polidocanol sclerotherapy of great saphenous veins and their tributaries in synchronous procedure.

BackgroundChronic venous insufficiency is a highly prevalent disease. Advanced cases have high morbidity.ObjectivesTo evaluate the risks and benefits of foam sclerotherapy in patients who underwent bilateral treatment of the great saphenous veins in a single procedure, in selected cases of advanced venous insufficiency.MethodsWe retrospectively reviewed 55 patients (110 limbs) with bilateral incompetence of the great saphenous veins who had undergone foam sclerotherapy treatment bilaterally, using a maximum dose of 20 ml of foam per patient and inelastic compression.ResultsIn 81 (73.6%) of the 110 saphenous veins analyzed, occlusion was obtained in the first session. After a second session this figure rose to 106 (96.3%) and all 110 (100%) veins were occluded after three sessions. Bilateral occlusion of the great saphenous veins was achieved in 27 patients (50%) in one session, in 34 (62%) patients in two sessions, and in 55 (100%) patients in three sessions. At 42 days after sclerotherapy, there was complete ulcer healing in seven (63%) of the 11 patients with ulcers and partial healing in 3 (27%) of these patients. One patient (1.8%) had self-limited lipothymia and visual scotomas, 3 patients (5.45%) had skin spots, and 19 patients (34.5%) developed retained intravascular coagulum.ConclusionsBilateral foam sclerotherapy in a synchronous procedure is an option to be considered for treatment of varicose veins of the lower limbs.

Descriptive model for distributed element synchronization digital radio networks of the IEEE 802.11s and IEEE 802.11p standards

Today, the basic radio communication standards for building self-organizing networks such as MANET, VANET and FANET are IEEE 802.11s and IEEE 802.11p. The link layer is responsible for establishing and conducting a communication session in these networks. It includes a variety of procedures, the main of which are synchronization procedures, random multiple media access, reserved media access and transmitter power control of network elements. Moreover, in digital radio communication networks of the IEEE 802.11 standards family, both centralized synchronization and distributed synchronization of such network elements are used. However, in digital radio networks of the IEEE 802.11s and IEEE 802.11p standards, the key procedure for establishing and conducting a communication session is the distributed synchronization of the network data elements. It should be noted that there is no descriptive model of distributed synchronization of the IEEE 802.11s and IEEE 802.11p standards digital radio communication network elements, taking into account these standards features. All elements of the IEEE 802.11s and IEEE 802.11p digital radio network send Beacons on a competitive basis. This occurs cyclically at the start of the repeating sync interval. In this regard, the occurrence of three events is possible: successful transmission of the synchronizing Beacon packet, its collision with a similar packet and a service or user data packet. To prevent (reduce) the number of collisions in a digital radio communication network, it is necessary to maintain a constant time difference between the internal time of all network elements. It is worth noting that maintaining a constant time difference for all digital radio communication network elements through guaranteed and timely sending of synchronizing Beacon packets is the main mechanism for distributed synchronization of such network elements. In the event that the calculated value of the time difference Toffsetni for one of the neighboring elements of the digital radio communication network does not coincide with the analogous value obtained in the past synchronization interval Toffsetni-1, then the correction of the own internal TTSF time of the IEEE 802.11s and IEEE 802.11p standards digital radio communication network element begins. The procedure for adjusting the network element internal time continues until the maximum value of this element internal time offset TMaxClockDrift is equal to zero. Also, to reduce or prevent collisions of synchronizing Beacon packets in the data transmission channel, each network element both initially, when entering the network, and immediately when collisions of synchronizing packets occur, Beacon selects and sets the timing parameters of synchronization so that they do not coincide with similar parameters of neighboring network elements. The developed descriptive model of the IEEE 802.11s and IEEE 802.11p standards digital radio communication network elements distributed synchronization includes algorithms for the such network elements functioning, adjusting the such elements intrinsic internal time, searching for an alternative value for the start time of a repeating synchronization interval and adjusting it. The presented model is applicable in the development of analytical and simulation models for assessing the IEEE 802.11s and IEEE 802.11p standards digital radio communication network performance, taking into account the distributed synchronization of such network elements.

Internetwork Time Synchronization of Mobile Ad Hoc Networks

Several time synchronous ad hoc networks may operate in the same geographical area. Although network time synchronization within an individual network has been widely discussed, internetwork time synchronization relying on time sources the networks carry has not been addressed. Therefore, this paper proposes an internetwork time synchronization procedure that allows to use one network as a time source and share its time, like a global navigation satellite system time, to other networks. The internetwork time synchronization procedure runs in gateway nodes that could be a member in several networks, and it collaborates with the individual network time synchronization algorithms that operate at the network level. Consequently, the paper proposes a generic, robust hybrid network time synchronization protocol and analyses its performance using a sensible metric called a mutual consensus. It is shown that the common time is achieved with a limited variance in the networks that operate in the master-slave, distributed or hybrid mode. Provided numerical examples illustrate the behavior of the algorithm and confirm the theoretical findings.

Synchronization of Chaotic Systems: A Generic Nonlinear Integrated Observer‐Based Approach

The purpose of this research is to study the synchronization of two integrated nonlinear systems with time delay and disturbances. A nonlinear system is a system in which the difference in output is not relative to the difference in input. A new control methodology for synchronization of the two chaotic systems master and slave is recognized by means of the unique integrated chaotic synchronous observer and the integrated chaotic adaptive synchronous observer. The instantaneous approximation states of the master and slave systems are accomplished by means of methods for suggesting observers for every one of the master and slave systems and by the production of error signals between these approximated states. This approximated synchronization error signal and state approximation errors meet at the origin by means of methods involving a particular observer‐based feedback control signal to ensure synchronization and state approximation. Using Lyapunov stability theory, adaptive and nonadaptive laws for control systems, and nonlinear properties, the intermingling conditions for state approximation errors and approximated synchronization errors are established as nonlinear matrix inequalities. A solution to the resulting inequality constraints using a two‐step linear matrix inequality (LMI)‐based approach is introduced, giving essential and adequate conditions to extract values from the controller gain and observer gain matrices. Simulation of the suggested synchronization procedure for FitzHugh–Nagumo neuronal systems is demonstrated to expand the viability of the suggested observer‐based control techniques.

Development of Self-Synchronized Drones’ Network Using Cluster-Based Swarm Intelligence Approach

Timing synchronization has a vital role in swarm drones' network (SDN) or a swarm of unmanned aerial vehicle (UAV) network. Current timing synchronization methods focus on enhancing single-hop skews which remarkably improve timing synchronization precision at this level. The improper clock of the drone system can cause interference, affect spectrum precision and interrupt the operation of the transceiver. In the drones' network, master drones' (MD) neighbor drone's timing synchronization approaches like Reference Broadcast System (RBS) realize a good performance. However, the requirement of one super drone with a large number of broadcasts for RBS makes it unrealistic to use in some situations like SDN network situation. Appropriate study and adjustments are needed to have real timing synchronization by eliminating the clocks drift and enhancing the timing synchronization precision. Therefore, a new self-timing synchronization approach is proposed in this paper where several MD drones can autonomously generate swarm clusters. The cluster head (CH) instigates a timing synchronization procedure starting with intra-Swarm cluster timing synchronization. The intermediate drones (ID) are elected between two swarm clusters to synchronize all drones in line with the inter-swarm cluster timing synchronization approach. The proposed approach is distributed and flexible to achieve high timing synchronization precision. The paper proposes a novel self-timing synchronization approach for in large scale semi-flat SND network architecture. Self-timing synchronization is swarm cluster-based and applicable for a huge number of master drones in SDN. One is the intra-Swarm cluster where the timing synchronization procedure starts with the CH to synchronize all CM. Secondly, in the inter-swarm cluster timing synchronization, two clusters are synchronized via intermediate drone (ID). However, the simulations demonstrated that in many cases all CHs are synchronized by the synchronized CHs from intra-swarm cluster timing synchronizations; this increased the system throughput and synchronization delay to about 75% compared to what we planned to achieve. Moreover, the simulation results also proved that the achieved synchronization precision can be used for position estimation and prediction with high accuracy.

Influence of diabetes on short-term outcome after major hepatectomy: an underestimated risk?

BackgroundPatient-related risk factors such as diabetes mellitus and obesity are increasing in western countries. At the same time the indications for liver resection in both benign and malignant diseases have been significantly extended in recent years. Major liver resection is performed more frequently in a patient population of old age, comorbidity and high rates of neoadjuvant chemotherapy. The aim of this study was to evaluate whether diabetes mellitus, obesity and overweight are risk factors for the short-term post-operative outcome after major liver resection.MethodsFour hundred seventeen major liver resections (≥ 3 segments) were selected from a prospective database. Exclusion criteria were prior liver resection in patient’s history and synchronous major intra-abdominal procedures. Overweight was defined as BMI ≥ 25 kg/m2 and < 30 kg/m2 and obesity as BMI ≥ 30 kg/m2. Primary end point was 90-day mortality and logistic regression was used for multivariate analysis. Secondary end points included morbidity, complications according to Clavien–Dindo classification, unplanned readmission, bile leakage, and liver failure. Morbidity was defined as occurrence of a post-operative complication during hospital stay or within 90 days postoperatively.ResultsFifty-nine patients had diabetes mellitus (14.1%), 48 were obese (11.6%) and 147 were overweight (35.5%). There were no statistically significant differences in mortality rates between the groups. In the multivariate analysis, diabetes was an independent predictor of morbidity (OR = 2.44, p = 0.02), Clavien–Dindo grade IV complications (OR = 3.6, p = 0.004), unplanned readmission (OR = 2.44, p = 0.04) and bile leakage (OR = 2.06, p = 0.046). Obese and overweight patients did not have an impaired post-operative outcome compared patients with normal weight.ConclusionsDiabetes has direct influence on the short-term postoperative outcome with an increased risk of morbidity but not mortality. Preoperative identification of high-risk patients will potentially decrease complication rates and allow for individual patient counseling as part of a shared decision-making process. For obese and overweight patients, major liver resection is a safe procedure.

Model-Based Predictive Rotor Current Control Strategy for Indirect Power Control of a DFIM Driven by an Indirect Matrix Converter

This paper presents a new control strategy using model-based predictive current control (MB-PCC) for a doubly fed induction machine (DFIM) driven by an indirect matrix converter (IMC). This strategy proposes the control of rotor currents, whose references are calculated from active and reactive stator power set points and the dynamic model of the DFIM. The control strategy works well in the four P-Q operating regions of the DFIM. The grid synchronization process is carried out by setting the P-Q power set points to zero. The results include the DFIM synchronization procedure as well as the active and reactive power control at variable shaft speed to validate the feasibility of the proposed strategy.

Compensation of physiological motion enables high-yield whole-cell recording in vivo

BackgroundWhole-cell patch-clamp recording in vivo is the gold-standard method for measuring subthreshold electrophysiology from single cells during behavioural tasks, sensory stimulations, and optogenetic manipulation. However, these recordings require a tight, gigaohm resistance, seal between a glass pipette electrode's aperture and a cell's membrane. These seals are difficult to form, especially in vivo, in part because of a strong dependence on the distance between the pipette aperture and cell membrane. New MethodWe elucidate and utilize this dependency to develop an autonomous method for placement and synchronization of pipette's tip aperture to the membrane of a nearby, moving neuron, which enables high-yield seal formation and subsequent recordings deep in the brain of the living mouse. ResultsThis synchronization procedure nearly doubles the reported gigaseal yield in the thalamus (>3 mm below the pial surface) from 26 % (n = 17/64) to 48 % (n = 32/66). Whole-cell recording yield improved from 10 % (n = 9/88) to 24 % (n = 18/76) when motion compensation was used during the gigaseal formation. As an example of its application, we utilized this system to investigate the role of the sensory environment and ventral posterior medial region (VPM) projection synchrony on intracellular dynamics in the barrel cortex. Comparison with Existing Method(s)Current methods of in vivo whole-cell patch clamping do not synchronize the position of the pipette to motion of the cell. ConclusionsThis method results in substantially greater subcortical whole-cell recording yield than previously reported and thus makes pan-brain whole-cell electrophysiology practical in the living mouse brain.

A New Non-Orthogonal Transceiver for Asynchronous Grant-Free Transmission Systems

The grant-free non-orthogonal multiple access (GF-NOMA) system, in which users autonomously transmit uplink data signals without carrying out a complicated random access process, offers significant advantages for increasing the efficiency of resource usage with low signaling overhead. In the proposed GF-NOMA system, since the collision resolution process is omitted and resources are not pre-assigned to users, multiple users may use same resource, without the base station (BS) being able to identify these collided users. In addition, in the absence of the UL synchronization procedure generally performed in the random access process, multiple users’ signals are received asynchronously. To solve these problems, we have developed a new transceiver structure for the GF-NOMA system consisting of a secondary preamble and a multiuser-multisymbol (MUMS) detector. The purpose of the secondary preamble is to successfully detect user access and estimate channel information even when no collision resolution process is being performed. The MUMS receiver is then proposed as a way to effectively mitigate the severe interference caused by the asynchronous transmission. Simulation results show that the proposed preamble structure and the receiver structure are superior to the conventional schemes. Furthermore, we show that the GF-NOMA system with the proposed transceiver structure achieves much better performance than other GF-NOMA systems in terms of reliability and successfully detected bits.

Utilization of Asynchronous and Synchronous Teledermatology in a Large Health Care System During the COVID-19 Pandemic.

Background: Teledermatology offers an opportunity to continually deliver care during the coronavirus disease 2019 pandemic. Objective: To provide quantitative data about the use of teledermatology. Methods: Retrospective analysis of teledermatology consultations was performed from March 16 to May 1, 2020. The number/type of encounters, differences in diagnoses, and prescriptions between asynchronous and synchronous teledermatology visits were analyzed. Results: A total of 951 visits (36.2%) were asynchronous whereas 1,672 visits (63.8%) were synchronous. Only 131 (<5%) visits required an acute in-person follow-up. The diagnosis of acne was more frequent with asynchronous visits (p < 0.002, Bonferroni corrected). Antibiotics and nonretinoid acne medications were prescribed more with asynchronous visits, whereas immunomodulators and biologics were more commonly prescribed with synchronous visits (p < 0.02, Bonferroni corrected). Providers at our institution were split on preferred mode (54.2% synchronous, 45.8% asynchronous); however, synchronous visits were preferred for complex medical dermatology patients and return patients (p < 0.05). Limitations: This study is limited by being a single-center study. Conclusions: Asynchronous teledermatology was used more for acne management, whereas synchronous teledermatology was preferable to providers for complex medical dermatology. Postanalysis of the data collected led us to institute a hybridization of our asynchronous and synchronous teledermatology.