Defense Acquisition Program Administration

Free Space Optical (FSO) networks, also known as optical wireless networks, have emerged as viable candidates for broadband wireless communications in the near future. The range of the potential application of FSO networks is extensive, from home to satellite. However, FSO networks have not been popularized because of insufficient availability and reliability. Researchers have focused on the problems in the physical layer in order to exploit the properties of wireless optical channels. However, recent technological developments with successful results make it practical to explore the advantages of the high bandwidth. Some researchers have begun to focus on the problems of network and upper layers in FSO networks. In this survey, we classify prospective global FSO networks into three subnetworks and give an account of them. We also present state-of-the-art research and discuss what kinds of challenges exist.

OBJECTIVE: The aim of this study is to evaluate the long-term outcomes of a large series of patients treated with submucosal tunneling endoscopic resection (STER). BACKGROUND: STER is a newly developed treatment for upper gastrointestinal submucosal tumors originating from the muscularis propria layer. Recently, reports about STER are increasing, but a large study with long-term follow-up is little known. METHODS: In a retrospective study, a total of 180 patients with upper gastrointestinal submucosal tumors undergoing STER were included from June 2011 to May 2013. Clinicopathological, endoscopic, and follow-up data were collected and analyzed. RESULTS: The en bloc resection was achieved in 90.6% of patients and the complications rate was 8.3%. Based on statistical analysis, tumors with irregular shape and greater size were the significant contributors to piecemeal resection and long operative times. Besides tumor shape and size, tumor in deep muscularis propria and long operative time were also risk factors of complications. The median hospitalization time was 3.2 days. All of the complications were cured by conservative treatment. A median follow-up of 36 months was available and all patients were free from local recurrence or distant metastasis during the study period. CONCLUSIONS: STER is an effective and safe methodology for the resection of upper gastrointestinal submucosal tumors. Tumor size and shape impact on the piecemeal resection rate and procedural difficulty. STER for large tumors with irregular shape in the deep muscularis propria is also feasible but associated with relatively high risks of piecemeal resection and complications.

A nanoindenter XP with scanning capabilities was used to perform nanoindentations on GaN and ZnO nanowires with radii in the range of 20–50nm, positioned on a silicon substrate and bonded to the substrate at their ends with platinum. Since the geometry of indentation of a nanowire differs significantly from the indentation of a half-space, the standard Oliver-Pharr method [W. C. Oliver and G. M. Pharr, J. Mater. Res. 7, 1564 (1992)] of analysis may not be used. A two interface contact model has been developed for the nanoindentation of a nanowire on a flat substrate, with the two interfaces, indenter/nanowire and nanowire/substrate, being in a series. The contact at the indenter/nanowire interface is modeled as an elliptical contact at the sphere (indenter)/cylinder interface. The contact at the nanowire/substrate interface is modeled as a contact at the cylinder/half-space interface under some concentrated forces applied on top of the cylinder. Under these latter conditions the cylinder may be expected to recede from the half-space when the load is applied. In order to predict the contact stiffness for the two interfaces, the theories of Hertzian contacts and receding contacts have been reviewed, generalized, and used. Considering the possible adhesion at the nanowire/substrate interface and the fixed ends of the nanowire, we have considered two limits for the contact at the nanowire/substrate interface: one with and one without separation at the interface; thus, we obtain two bounds for the contact stiffness and hardness. The model has been used to analyze the nanoindentation data for GaN and ZnO nanowires. We found that the hardness of the GaN nanowire is 46.7±5.6GPa, which is much higher than that of the ZnO nanowire, 3.4±0.9GPa. We also found that the Oliver-Pharr hardness [W. C. Oliver and G. M. Pharr, J. Mater. Res. 7, 1564 (1992)] may be the rough lower bound of the hardness and the Joslin-Oliver hardness [D. L. Joslin and W. C. Oliver, J. Mater. Res. 5, 123 (1990)] may be the rough upper bound of the hardness.

Millimeter wave (mmWave) communications in the 60 GHz band can provide multi-gigabit rates for emerging bandwidth-intensive applications, and has thus gained considerable interest recently. In this paper, we investigate the problem of efficient scheduling in mmWave wireless personal area networks (WPAN). We develop a frame-based scheduling directional MAC protocol, termed FDMAC, to achieve the goal of leveraging collision-free concurrent transmissions to fully exploit spatial reuse in mmWave WPANs. The high efficiency of FDMAC is achieved by amortizing the scheduling overhead over multiple concurrent, back-to-back transmissions in a row. The core of FDMAC is a graph coloring-based scheduling algorithm, termed greedy coloring (GC) algorithm, that can compute near-optimal schedules with respect to the total transmission time with low complexity. The proposed FDMAC is analyzed and evaluated under various traffic models and patterns. Its superior performance is validated with extensive simulations.

A novel nanoreservoir made of carbon nanotubes (CNTs) is proposed for realizing tougher and automated self-healing materials. The advantages of the approach are that CNTs have the potential to play the role of reinforcing elements prior to and after sealing a crack and that the number of voids is reduced after the material and the CNTs themselves are healed. The focus of this paper is on investigating the feasibility of using CNTs as a nanoreservoir by analyzing the dynamics of a fluid flowing out of a ruptured single-walled CNT (SWNT), where the fluid resembles an organic healing agent. With this in mind the escaping mechanism of organic molecules stored inside a cracked SWNT was investigated through a molecular dynamics study. The study shows that, when a SWNT wall suffers the formation of a crack, a certain amount of organic molecules, stored inside the SWNT, escape into space in a few picoseconds. This phenomenon is found to depend on the temperature and on the size of the cracks. The results of this study indicate that CNTs have the potential to be successfully used to realize the next generation of stronger, lighter and self-healing materials.

BACKGROUND: Hepatocellular carcinoma (HCC) with main portal vein tumor thrombus (MPVTT) is often associated with poor prognosis. We retrospectively assessed the effectiveness of percutaneous transhepatic portal vein stenting and transarterial chemoembolization (PTPVS-TACE) combined with or without 3-dimensional conformal radiotherapy (3-DCRT) for HCC with MPVTT. METHODS: Forty-five patients with HCC complicated by MPVTT were treated with PTPVS-TACE. Among them, 16 patients (group A) received 3-DCRT with 30-60Gy as daily 2Gy fractions. The remaining 29 patients (group B) received no radiotherapy. The tumor responses, complications, stent patency rates, and cumulative survival rates were evaluated, and the Kaplan-Meier method and log-rank test were used for survival analysis. RESULTS: No severe complications were associated with PTPVS-TACE and 3-DCRT. The objective response rate (CR and PR) was 35.6%. The 60-, 180-, and 360-day cumulative stent patency rates were 93.3%, 62.2%, and 34.6% in group A, and 58.6%, 21.7%, and 10.8% in group B, respectively, showing significant difference between the 2 groups (P<.01). The mean patency time was 475.20+/-136.97 and 199.58+/-61.40 days, respectively. The 60-, 180-, and 360-day cumulative survival rates were 93.8%, 81.3%, and 32.5%, respectively, for group A, 86.2%, 13.8%, and 6.9%, respectively, for group B. Significant statistical differences were detected between the 2 groups (P<.01). CONCLUSIONS: These findings suggest that sequential therapy by PTPVS-TACE-3-DCRT is possibly an effective treatment modality for HCC complicated by main portal vein tumor thrombus.

Precision swine production can benefit from autonomous, noninvasive, and affordable devices that conduct frequent checks on the well-being status of pigs. Here, we present a remote monitoring tool for the objective measurement of some behavioral indicators that may help in assessing the health and welfare status-namely, posture, gait, vocalization, and external temperature. The multiparameter electronic sensor board is characterized by laboratory measurements and by animal tests. Relevant behavioral health indicators are discussed for implementing machine learning algorithms and decision support tools to detect animal lameness, lethargy, pain, injury, and distress. The roadmap for technology adoption is also discussed, along with challenges and the path forward. The presented technology can potentially lead to efficient management of farm animals, targeted focus on sick animals, medical cost savings, and less use of antibiotics.

BACKGROUND: The prevalence of nonalcoholic fatty liver disease (NAFLD) has significantly increased over the last decades. Despite existence of several interventions, there remains unclear which interventions work the best. METHODS: A systematic review and network meta-analysis of randomized trials comparing efficacy of all treatment options in NAFLD were performed to determine comparative efficacy and safety of interventions in the management of NAFLD. Several electronic databases were searched up to Nov 15, 2015. Outcomes include liver histological outcomes (i.e., fibrosis), all-cause mortality, cirrhosis, and safety. A network meta-analysis was applied to estimate pooled risk ratios (RR). Quality of evidence was assessed using GRADE criteria. RESULTS: A total of 44 studies (n = 3802) were eligible. When compared with placebo, obeticholic acid (OCA) was the only intervention that significantly improved fibrosis with RR (95% CI) of 1.91 (1.15, 3.16), while pentoxyfylline (PTX) demonstrated improved fibrosis without statistical significance with RR (95% CI) of 2.27 (0.81, 6.36). Only thiazolidinedione (TZD) and vitamin E use resulted in significant increase in resolution of NASH, while OCA, TZD, and vitamin E significantly improved other outcomes including NAS, steatosis, ballooning, and inflammation outcomes. Quality of evidence varied from very low (i.e., metformin, PTX on mean change of ballooning grade) to high (OCA, TZD, vitamin E on improving histological outcomes). Limitations of this study were lack of relevant long-term outcomes (e.g., cirrhosis, death, safety), possible small study effect, and few head-to-head studies. CONCLUSIONS: Our study suggests potential efficacy of OCA, TZD, and vitamin E in improving histologic endpoints in NAFLD. These findings are however based on a small number of studies. Additional studies are awaited to strengthen this network meta-analysis.

In this letter, we propose a broadband reconfigurable antenna for aircraft communication that covers the VHF/UHF/L-bands (30-300/300-400/960-1220 MHz). The proposed antenna structure is a modified biconical unipole antenna. The antenna is frequency-reconfigurable using a p-i-n diode switch. In the on state, the antenna operates as a V-type traveling antenna and covers 30-300 and 960-1150 MHz. In the off state, the antenna operates as a unipole antenna and covers 300-400 and 1150-1220 MHz. The maximum power dissipation of the proposed antenna is 18 W. The proposed antenna has VSWR <; 2.5 for all bands. Antenna gain is less than 1.8 dBi at 30-400 MHz and 2.5 dBi at 960-1220 MHz.

This study presents a novel hybrid deep learning model for arrhythmia classification from electrocardiogram signals, utilizing the stockwell transform for feature extraction. As ECG signals are time-series data, they are transformed into the frequency domain to extract relevant features. Subsequently, a CNN is employed to capture local patterns, while a transformer architecture learns long-term dependencies. Unlike traditional CNN-based models that require R-peak detection, the proposed model operates without it and demonstrates superior accuracy and efficiency. The findings contribute to enhancing the accuracy of ECG-based arrhythmia diagnosis and are applicable to real-time monitoring systems. Specifically, the model achieves an accuracy of 97.8% on the Icentia11k dataset using four arrhythmia classes and 99.58% on the MIT-BIH dataset using five arrhythmia classes.

We examine a scheduling problem for a dual-armed cluster tool that processes multiple similar wafer types concurrently. It has been recently proved that the well-known swap sequence, which is widely used for single wafer type processing, also minimizes the cycle time for concurrent processing. In this article, we wish to minimize wafer delays in a process chamber, which are critical to wafer quality degradation, while maintaining the minimum cycle time. In particular, we show that concurrent processing of wafers with different processing times complicates the analysis of wafer delays significantly, and the wafer delays can be remarkably reduced by finding a proper cycle plan which is the release sequence of different wafer types. We first characterize wafer delays for a given cycle plan by analyzing the circuits of the timed event graph (TEG) model. From this, we prove that concurrent processing of wafers may cause a significant workload imbalance between parallel chambers of a process step, and hence the wafer delays increase substantially. We present that the wafer delays are minimized by a cycle plan that evenly balances workloads between parallel chambers. We also propose how wafer loading task at each process step has to be postponed to meet wafer delay constraints while maintaining the minimum cycle time. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Wafer quality control has become an essential fab operational problem in semiconductor manufacturing industry. In cluster tools, which are dominantly being used for diverse wafer fabrication stages, it has been proven that the wafer delays within process chambers have a crucial impact on the wafer quality. Accordingly, modern fabs have introduced stringent quality control to regulate wafer delays in cluster tools. In this research, we propose a scheduling strategy to minimize the wafer delays when a cluster tool concurrently processes multiple wafer types. We first show that the release sequence of different wafer types significantly impacts the wafer delays under concurrent processing, and we then propose how these wafer delays can be minimized by finding the optimal wafer release sequence.

As the order size for modern fabs tends to be smaller, fabs wish to process a class of similar wafer lots at a tool concurrently to reduce the work-in-progress lots as well as the total manufacturing lead time. We examine a scheduling problem for a dual-armed cluster tool that simultaneously produces multiple wafer types with identical wafer flow patterns but different process times. We prove that the conventional swap sequence, which is optimal and prevalently being used for single-wafer-type processing, is also optimal for such concurrent processing. We then propose a way of determining a release sequence of wafer types into the tool, called cycle plan, that maximizes the utilization of parallel chambers and hence increases the tool throughput rate. We present conditions for which the parallel chambers are shared by all wafer types and their workloads are evenly balanced so as to maximize the throughput rate. We also report the experimental results.

PURPOSE: To investigate the influence of periocular radiotherapy on meibomian glands. METHODS: We evaluated 28 patients (40 eyes) who received radiotherapy (RT group) for conjunctival or orbital lymphoma and 30 age-matched control subjects (60 eyes). Subjects underwent slit-lamp examination of the eyelids, Schirmer test, meibography, and evaluation of tear film breakup time (TBUT), Ocular Surface Disease Index (OSDI) scores, meibomian glands evaluation (meiboscore, meibum expressibility, and lid margin abnormality scores), and tear film lipid layer thickness using an ocular surface interferometer. These parameters were compared between subjects in the RT and control groups. RESULTS: Meiboscores as well as meibum expressibility and OSDI scores in the RT group were significantly higher compared with those in the control group (1.6 ± 0.9 vs. 0.4 ± 0.6, 1.6 ± 1.0 vs. 0.2 ± 0.4, and 48.1 ± 21.4 vs. 6.2 ± 4.4, respectively, P < 0.001, all), whereas the Schirmer value (9.2 ± 5.1 vs. 12.3 ± 5.2, P = 0.004), TBUT (4.2 ± 2.5 vs. 6.4 ± 2.6, P = 0.001), and lipid layer thickness (61.0 ± 29.3 vs. 85.2 ± 20.0, P < 0.001) in the RT group were lower compared with those in the control group. The percentage of meibomian gland dropout was significantly correlated with age (P = 0.025) and total radiation dose (P = 0.012), regardless of the target location of irradiation. Even low-dose irradiated eyes (<30 Gy) exhibited significantly higher meiboscores (P < 0.001) and shorter TBUT (P = 0.005) compared with control eyes. CONCLUSIONS: Eyes that received periocular radiotherapy exhibited relatively high tear film instability induced by meibomian gland dysfunction, contributing to the high severity of dry eye symptoms.

Quasi-optical imaging systems require low blurring effect and large depth of focus (DOF) to get an acceptable sharpness of the image. To reduce aberration-limited blurring, the aspheric convex plano lenses with an aperture diameter of 350 mm are designed in W-band. We analyzed theoretically and experimentally the millimeter-wave band lens characteristics, such as beam spot size, spatial resolution (SR), and DOF, via f-number. It is first used to verify the DOF through f-number in the system-level test with the developed W-band radiometer imaging system. We have confirmed that the larger f-number of quasi-optical lens leads to a larger DOF but a lower SR.

Objective: Ixekizumab is a high-affinity monoclonal antibody that selectively targets interleukin-17A and is approved for treating moderate-to-severe psoriasis. This phase 3, multicenter, randomized, double-blind, placebo-controlled trial (NCT03364309; registered December 6, 2017) evaluated the safety and efficacy of ixekizumab in Chinese patients with moderate-to-severe psoriasis. Methods: 438 patients were randomized 2:2:1 to 80 mg ixekizumab every 2 weeks (IXE Q2W, n = 176), 80 mg ixekizumab every 4 weeks (IXE Q4W, n = 174), or placebo ( n = 88). Efficacy was assessed by evaluating the static Physician’s Global Assessment score of 0 or 1 (sPGA [0,1]) and Psoriasis Area and Severity Index (PASI) 75/90/100 responses, and nonresponder imputation was used for handling missing data. The safety profile was evaluated by assessing treatment emergent adverse events (AEs) and serious AEs. Results: At week 12, the sPGA (0,1) response rates were 3.4%, 79.9%, and 86.4% in the placebo, IXE Q4W, and IXE Q2W groups, respectively. The PASI 75/90/100 response rates were 8.0%/2.3%/0.0%, 87.4%/75.9%/29.3%, and 93.8%/82.4%/33.0% in the placebo, IXE Q4W, and IXE Q2W groups, respectively. Ixekizumab led to rapid PASI 50 responses, as early as week 1, whereas PASI 75 and sPGA (0,1) responses were observed from week 2. sPGA (0,1) and sPGA (0) responses were maintained through week 60 in a higher proportion of patients receiving IXE Q4W vs. placebo. The safety profile was consistent with previous studies of ixekizumab in psoriasis. Conclusion: Ixekizumab showed a rapid onset of action and high efficacy that was maintained through 60 weeks and was well tolerated with no unexpected AEs, in Chinese patients with moderate-to-severe plaque psoriasis.

This paper proposes a new time division multiple access (TDMA) based multi-hop resource(slots) reservation protocol (TMRR) for tactical mobile adhoc networks (T-MANET). TMRR lets a node reserve the channel resource for multi-hop packet transmission in consecutive order, so that the packet transmission between a source node and a multi-hop away destination node is possible within a superframe. This paper evaluates the performance of the proposed protocol via OPNET simulation in terms of the average end-to-end delay and the average throughput in both static and mobile environments. And this paper compares it to that of the Evolutionary-TDMA (E-TDMA) which is a representative reservation-based medium access control (MAC) protocol considering node mobility in MANET. According to the simulation results of the single-hop scenarios, TMRR gives better packet throughput and delay performance than E-TDMA as the offered traffic is increased. For the multi-hop scenarios, the average end-to-end delay of TMRR nodes meets the multi-hop end-to-end delay requirements because a node can transmit the packets to a multi-hop away node within a superframe.

We present a (suboptimal) filtering algorithm for tracking highly maneuvering targets in a cluttered environment using multiple sensors. We concentrate on two targets which temporarily move in close formation, giving rise to a single detection due to the resolution limitations of the sensor. The filtering algorithm is developed by applying the basic interacting multiple model (IMM) approach and a joint probabilistic data association with merged measurements (JPDAM) technique and coupled target state estimation to a Markovian switching system. The algorithm is illustrated via two simulation examples. Compared with an existing IMM/JPDA (joint probabilistic data association) filtering algorithm developed without accounting for merged measurements, the proposed algorithm achieves significant improvement in both the accuracy of track estimation during target merging period and the number of lost tracks.

Systematic performance appraisal and ranking of candidates applying for promotion is important in strategic human resource management. In military organizations, it is particularly crucial to evaluate candidates for promotion and placement because their functions directly impact operations and national security. This paper proposes a framework that can be used to evaluate candidates based on unique performance evaluation criteria. The framework allows determination of the most qualified candidate by considering both quantitative scores and qualitative characteristics of his or her performance. It also ensures fairness, objectivity and transparency since evaluators first determine the metrics of performance evaluation as well as the weighting among the metrics before aggregating the appraisal scores to determine the ranking of each candidate. The ranking is determined by applying the fuzzy set operations and membership function. In order to decide the promotion rank of candidates, we propose a fuzzy ranking procedure in conjunction with a novel integrated performance appraisal and promotion ranking system.

The SAD (safety and arming device) is an indispensable fuse component that ensures safe and reliable performance during the use of ammunition. Because the application of electronic devices for smart munitions is increasing, miniaturization of the SAD has become one of the key issues for next-generation artillery fuses. Based on MEMS technology, various types of miniaturized SADs have been proposed and fabricated. However, none of them have been reported to have been used in actual munitions due to their lack of high impact endurance and complicated explosive train arrangements. In this research, a new MEMS SAD using a ball driven mechanism, is successfully demonstrated based on a UV LIGA (lithography, electroplating and molding) process. Unlike other MEMS SADs, both high impact endurance and simple structure were achieved by using a ball driven mechanism. The simple structural design also simplified the fabrication process and increased the processing yield. The ball driven type MEMS SAD performed successfully under the desired safe and arming conditions of a spin test and showed fine agreement with the FEM simulation result, conducted prior to its fabrication. A field test was also performed with a grenade launcher to evaluate the SAD performance in the firing environment. All 30 of the grenade samples equipped with the proposed MEMS SAD operated successfully under the high-G setback condition.

The present study aims to assess test uncertainty assessment method of nominal wake field measurement by a Stereoscopic Particle Image Velocimetry (SPIV) system in a towing tank. The systematic uncertainty of the SPIV system was estimated from repeated uniform flow measurements. In the uniform flow measurement case, time interval between image frames and uniform flow speed were varied to examine the effects of particle displacement and flow around the SPIV system on the systematic standard uncertainty. The random standard uncertainty was assessed by repeating nominal wake field measurements and the estimated random standard uncertainty was compared with that of laser Doppler velocimetry. The test uncertainty assessment method was applied to nominal wake measurement tests of a very large crude oil carrier model ship. The nominal wake measurement results were compared with existing experimental database by other measurement methods, with its assessed uncertainty.