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The sparse property of a direct adaptive equalizer (DAE) for single-carrier underwater acoustic communications is well recognized. It has been used to improve the performance and/or reduce the complexity of a DAE. Extensive investigations have been performed in terms of performance improvement. On the contrary, research on complexity reduction remains preliminary. A fundamental way for reducing the complexity of a DAE is to keep only significant taps while discarding trivial taps, that is, to run a partial-tap DAE. Existing partial-tap DAE designs assume a slowly varying sparse structure and may suffer performance degradation under a severe underwater environment. Motivated by this fact, the dynamic compressed sensing (DCS) technique is resorted to and a partial-tap DAE based on the sparse adaptive orthogonal matching pursuit-affine projection algorithm is proposed. The sparse adaptive orthogonal matching pursuit-affine projection algorithm-direct adaptive equalizer (SpAdOMP-APA-DAE) achieves symbol-wise updating of both positions and values of the significant coefficients. In this paper, a more extensive study on DCS-based DAEs is performed, and an enhanced dynamic compressed sensing-direct adaptive equalizer design enabled by the sparse adaptive subspace pursuit-improved proportionate affine projection algorithm (SpAdOMP-IPAPA) is proposed. The sparse adaptive subspace pursuit-improved proportionate affine projection algorithm-direct adaptive equalizer enjoys lower complexity while better performance than the previous SpAdOMP-APA-DAE. Experimental results corroborated the superiority of the SpAdOMP-IPAPA-DAE.

Purpose Combination of regional anaesthesia technique that is most effective in analgesia and postoperative functional outcome with the fewest complications needs investigation. Interspace between the popliteal artery and the capsule of the posterior knee block (IPACK) has been introduced clinically. We evaluated the efficacy of IPACK in combination with other nerve blocks after total knee arthroplasty. Methods Data were obtained from PubMed, Cochrane Library, Web of Science, and Sciencedirect. Studies that compared outcomes using IPACK combined with other regional nerve blocks after total knee arthroplasty with other analgesic modalities and those which used pain scores or opioid consumption as primary or secondary outcomes were included. Results Seventeen articles (20 trials, 1652 patients) were included. IPACK supplementation significantly reduced rest pain scores after total knee arthroplasty at postoperative hours 8–12(95%CI − 0.85 [− 1.36, − 0.34], I2 = 94%, p = 0.001), postoperative day 1 (95% CI − 0.49 [− 0.85, − 0.14], I2 = 87%, p = 0.006), and postoperative day 2 (95% CI − 0.28 [− 0.51, -0.05], I2 = 72%, p = 0.02); there was no significant difference at postoperative day 3 or discharge (95% CI − 0.14 [− 0.33, 0.05], I2 = 0%, p = 0.14). Combination treatment resulted in reduced dynamic pain scores at postoperative hours 8–12 (95%CI − 0.52 [− 0.92, − 0.12], I2 = 86%, p = 0.01) and postoperative day 1(95% CI − 0.49 [− 0.87, − 0.11], I2 = 88%, p = 0.01). There was no difference between postoperative day 2(95% CI − 0.29 [− 0.63, 0.05], I2 = 80%, p = 0.09), postoperative day 3 or discharge (95% CI − 0.45 [− 0.92, 0.02], I2 = 83%, p = 0.06). In addition, it strongly reduced postoperative opioid consumption within 24 H (95% CI − 0.76 [− 1.13, − 0.39], I2 = 85%, p 0.00001), 24–48 H (95% CI − 0.43 [− 0.85, − 0.01], I2 = 83%, p = 0.04), and total opioid use (95% CI − 0.64 [− 1.07, − 0.22], I2 = 86%, p = 0.003). Although IPACK supplementation improved timed up and go test and walking distance at postoperative day 2, there was no statistically significant difference at other time periods or obvious improvement in knee range of motion and quadriceps strength. IPACK block supplementation could shorten the length of stay (LOS) (95% CI − 0.40 [− 0.64, − 0.15], I2 = 70%, p = 0.001) and improve patient satisfaction (95% CI 0.43 [0.01, 0.84], I2 = 87%, p = 0.04). Conclusion Based on these results, IPACK supplementation, in addition to standard postoperative analgesia, can be used effectively and safely to relieve early postoperative pain after total knee arthroplasty.

Background: To explore the surgical technique and clinical outcomes of cementless total hip arthroplasty (THA) combined with impacted bone grafting in treating moderate and severe acetabular protrusion with rheumatoid arthritis (RA). Methods: From January 2010 to October 2020, 45 patients (56 hips) with RA secondary to acetabular invagination were treated with biological prosthesis THA combined with autologous bone grafting in our hospital, including 17 males (22 hips) and 28 females (34 hips). According to Sotello-Garza and Charnley classification criterion, there were 40 cases（49 hips）of typeⅡ(protrusio acetabuli 6-15 mm), and 5 cases（7 hips）of type Ⅲ (protrusio acetabuli ＞15 mm). At the postoperative follow-up, the ROM of the hip joint, the VAS score, and the Harris score were evaluated. The healing of the bone graft, the restoration of the hip rotation center, and the prosthesis loosening were assessed by plain anteroposterior radiographs. Results: The average operation time was 95.53 ± 22.45 min, and the mean blood loss was 156.16 ± 69.25 mL. There were no neurovascular complications during the operation. The mean follow-up duration was 5.20 ± 1.20 years. The horizontal distance of the hip rotation center was increased from preoperative 10.40 ± 2.50 mm to postoperative 24.03 ± 1.77 mm, and the vertical distance was increased from preoperative 72.36 ± 3.10 mm to postoperative 92.48±5.31 mm. The range of flexion motion of the hip joint increased from 39.48 ± 8.36° preoperatively to 103.07 ± 7.64° postoperatively, and the range of abduction motion increased from 10.86 ± 4.34° preoperatively to 36.75 ± 3.99° postoperatively. At the last follow-up, the Harris score increased from 37.84 ± 4.74 to 89.55 ± 4.05. All the patients could move independently without assistance. Conclusions: Cementless THA combined with impacted grafting granule bone of the autogenous femoral head and biological acetabular cup can reconstruct the acetabulum, restore the rotation center of the hip joint, and achieve good medium-term outcomes in the treatment of moderate and severe acetabular protrusion secondary to RA.

Defects in the optical lens directly affect the scattering properties of the optical lens and decrease the performance of the optical element. Although machine vision instead of manual detection has been widely valued, the feature fusion technique of series operation and edge detection cannot recognize low-contrast and multi-scale targets in the lens. To address these challenges, in this study, an improved YOLOv5-C3CA-SPPF network model is proposed to detect defects on the surface and inside of the lens. The hybrid module combining the coordinate attention and CSPNet (C3) is incorporated into YOLOv5-C3CA for improving the extraction of target feature information and detection accuracy. Furthermore, an SPPF features fusion module is inserted into the neck of the network model to improve the detection accuracy of the network. To enhance the performance of supervised learning algorithms, a dataset containing a total of 3800 images is created, more than 600 images for each type of defect samples. The outcome of the experiment manifests that the mean average precision (mAP) of the YOLOv5-C3CA-SPPF algorithm is 97.1%, and the detection speed FPS is 41 f/s. Contrast to the traditional lens surface defects detection algorithms, YOLOv5-C3CA-SPPF can detect the types of optical lens surface and inside defects more accurately and quickly, the experimental results show that the YOLOv5-C3CA-SPPF model for identifying optical lens defects has good generalizability and robustness, which is favorable for on-line quality automatic detection of optical lens defects and provide an important guarantee for the quality consistency of finished products.

The kill chain is important for forming system-combat capabilities based on an information system and improving combat effectiveness. The closed-loop time is one of the most important indexes characterizing the efficiency of the kill chain. The combat process has considerable uncertainties; the expression of the uncertainties and evaluation of the efficiency of the kill chain provide basic groundwork in kill chain research. In this paper, we construct three types of kill chain models based on the typical combat system and process, which are chain, network without loop, and network with loop. We then introduce three different closed-loop time calculations for the three models based on stochastic methods to express the uncertainties in the completion time, completion situation, and transformation situation of the activities in the kill chain. The results of this paper provide a theoretical basis and technical support with respect to problems in modeling, evaluating the effectiveness, and constructing the kill chain.

In this contemporary era, the importance of information is undisputed, but there has never been a common understanding of information, nor has a unanimous conclusion been reached by studies conducted on information metrics. On the basis of previous studies conducted, this paper analyzes the important achievements in research conducted into the properties and metrics of information, as well as their main insufficiencies, and discusses the essence, connotations, mathematical expressions, and basic problems related to information. On the basis of the understanding of the objectivity of information, it then proposes definitions and a sextuple model of objective information, discusses the basic properties of information, and explores the definitions and mathematical expressions of nine kinds of information metrics: extensity, detailedness, sustainability, richness, containability, delay, distribution, validity, and matchability. Through these metrics, this paper establishes a basic underlying framework for objective information theory that provides comprehensive support for systematic analysis and research on information and information systems.

In the contemporary era, the importance of information is undisputed, but there has never been a common understanding of information, nor a unanimous conclusion to the researches on information metrics. Based on the previous studies, this paper analyzes the important achievements in the researches of the properties and metrics of information as well as their main insufficiencies, and explores the essence and connotation, the mathematical expressions and other basic problems related to information. On the basis of the understanding of the objectivity of information, it proposes the definitions and a Sextuple model of information; discusses the basic properties of information, and brings forward the definitions and mathematical expressions of nine kinds of metrics of information, i.e., extensity, detailedness, sustainability, containability, delay, richness, distribution, validity and matchability. Through these, this paper establishes a basic theory frame of Objective Information Theory to support the analysis and research on information and information system systematically and comprehensively., Comment: 20 pages