Frame Interval Research Articles

Deforestation mapping sampling designs for Canadian landscapes

Deforestation is the direct human-induced conversion of forest to nonforest land uses. It is important for nations to understand and report the extent of their deforestation. Because of the vastness of Canada’s forest and the rare and spatially diverse nature of its deforestation, a sampling approach in which deforestation is mapped and then scaled up to represent deforestation for different regions was needed. The effectiveness of different sample designs in capturing the area of deforestation was evaluated using a Monte Carlo approach in which alternate sample designs were applied to simulated forest landscapes representative of different regions and deforestation patterns in Canada. Sampling error as expressed by the standard error in the estimated deforestation level for the sample divided by actual deforestation of the simulated landscape was used as a measure of sample design performance. Results indicated that sampling error was dependent on the characteristics of the deforestation (e.g., amount, shape, size, and distribution). For example, as mean event size increases or the proportion of linear deforestation events (e.g., roads and corridors) decreases, the required sampling intensity to reach a certain level of sampling error increases, and landscapes with a small number of very large events required the largest sampling intensity. To achieve a relative sampling error target (standard error / sample mean) of 10%, given sample designs of square plots on a systematic grid, a sample of 15%–25% of a landscape will be required for most Canadian landscapes, given a 10-year mapping time frame (interval between samples) and assuming a deforestation rate of 0.025% per annum. With mapping over a 5-year period, the required sampling intensity rises to 20%–40%. Also discussed are the consequences of the sampling error of different designs on the uncertainty in estimated greenhouse gas emission resulting from deforestation.

Prototype of Virtual Full Duplex via Rapid On-Off-Division Duplex

We design and implement a software-radio system for rapid on-off-division duplex (RODD), a scheme to achieve virtual full-duplex communication at the level of a transmission frame. RODD is based on the insight that it is not necessary to separate a node's transmission and reception at the timescale of a frame. Instead, RODD allows each node in a network to follow a different random on-off signaling signature to transmit during its own on-slots and listen to its neighbors through its own off-slots. Over one frame interval, each node broadcasts its message to its neighbors while recovering its neighbors' messages from the superposed signals received via its own off-slots. In this paper, we describe an RODD prototype to prove its key concepts, including redesigned synchronization and coding schemes. Simulation results are presented for comparison with the measurements obtained from a software-defined radio implementation of RODD. The effects of on-off signaling on the performance are investigated experimentally. In particular, the bit error rate is measured and compared with the simulation results. Our results indicate that virtual full duplex is feasible on a USRPs/LabVIEW platform via RODD.

Temporal averaging of two-dimensional correlation functions for velocity vector imaging of cardiac blood flow.

Ultrasonic imaging of blood flow in the cardiac lumen is a very useful tool to evaluate the pumping function of the human heart. The speckle tracking technique makes it possible to estimate the blood velocity vector. However, a stable estimation of the velocity vector of blood flow is difficult because signal-to-noise ratios of echoes from tiny blood particles are low. In this study, the speckle tracking technique with averaging of multiple two-dimensional correlation functions was employed for stable estimation of the blood velocity vector. Multiple two-dimensional correlation functions can be averaged during a very short period by using the echo data acquired by high-frame-rate echocardiography with diverging beam transmission. A steady flow experiment using blood-mimicking fluid (mean fluid velocity 0.2 m/s, flow angle 56° from the transducer surface) was implemented to investigate the effect of the averaging of two-dimensional correlation functions at a frame rate of 6024 Hz. First, to examine the averaging duration required for stable estimation of the flow velocity vector, the accuracies of vector estimates were evaluated at different durations for averaging of two-dimensional correlation functions in the steady flow measurement. It was found that the proposed averaging process with an averaging duration of over 8 frames could reduce the directional error in vector estimation to almost half that of the conventional speckle tracking technique. In subsequent experiments, the averaging duration was set at 12 frames corresponding to 2 ms. Measurements of steady flow at higher velocities were further implemented. The steady flow measurements with higher flow velocities of 0.4 and 0.6 m/s were simulated by changing the frame interval of the echo data at a flow velocity of 0.2 m/s. Although the averaging duration was a mere 2 ms, directional errors at mean flow velocities of 0.2, 0.4, and 0.6 m/s were reduced significantly. In an in vivo experiment of the healthy human heart, to produce a fine B-mode image, the diverging wave transmissions with different steered angles for compounding were interleaved in the transmission sequence. From the in vivo experimental result, the blood velocity vector of the left ventricular cavity showed the flow getting into/out of the cavity in ejection and early diastolic phases. Furthermore, estimated flow directions revealed rotating flow in the cavity in mid-diastole. Our proposed method has the feasibility to visualize the vortex flow by velocity vector mapping without a contrast agent.

2A1-R05 時速100kmの運動対象を計測する実時間オプティカルフローシステム

Real-time full-pixel optical flow estimation is conducted for 512 x 512 images by accelerating the Lucas-Kanade method on a CPU-based high-speed vision system. Our system can remarkably expand the measurable range of the estimate flows by implementing a novel algorithm that can optimally select frame intervals and space intervals in optical flow estimation according to the estimated flow speed. Its effectiveness is verified by showing estimated motion distributions for high-speed objects moving at 100 km/h or more.

Transient x-ray diffraction with simultaneous imaging under high strain-rate loading.

Real time, in situ, multiframe, diffraction, and imaging measurements on bulk samples under high and ultrahigh strain-rate loading are highly desirable for micro- and mesoscale sciences. We present an experimental demonstration of multiframe transient x-ray diffraction (TXD) along with simultaneous imaging under high strain-rate loading at the Advanced Photon Source beamline 32ID. The feasibility study utilizes high strain-rate Hopkinson bar loading on a Mg alloy. The exposure time in TXD is 2-3 μs, and the frame interval is 26.7-62.5 μs. Various dynamic deformation mechanisms are revealed by TXD, including lattice expansion or compression, crystal plasticity, grain or lattice rotation, and likely grain refinement, as well as considerable anisotropy in deformation. Dynamic strain fields are mapped via x-ray digital image correlation, and are consistent with the diffraction measurements and loading histories.

Virtual Full Duplex Wireless Broadcasting via Compressed Sensing

A novel solution is proposed to undertake a frequent task in wireless networks, which is to let all nodes broadcast information to and receive information from their respective one-hop neighboring nodes. The contribution in this paper is twofold. First, as each neighbor selects one message-bearing codeword from its unique codebook for transmission, it is shown that decoding their messages based on a superposition of those codewords through the multiaccess channel is fundamentally a problem of compressed sensing. In the case where each message is designed to consist of a small number of bits, an iterative algorithm based on belief propagation is developed for efficient decoding. Second, to satisfy the half-duplex constraint, each codeword consists of randomly distributed on-slots and off-slots. A node transmits during its on-slots and listens to its neighbors only through its own off-slots. Over one frame interval, each node broadcasts a message to its neighbors and simultaneously receives the superposition of neighbors' signals through its own off-slots and then decodes all messages. The proposed solution fully exploits the multiaccess nature of the wireless medium and addresses the half-duplex constraint at the fundamental level. In a network consisting of Poisson distributed nodes, numerical results demonstrate that the proposed scheme often achieves several times the rate of slotted ALOHA and CSMA with the same packet error rate.

A Contention-Based Transmission Strategy for Distributed Radar Sensor Network

A channel-sharing method was proposed to improve the energy efficiency per detection task in distributed radar sensor network. The sensor nodes transmitted their local test statistics (LTS) to the fusion center in approximately descending order of their LTSs by modifying the value of backoff timer and frame interval according to the value of their LTSs. Simulation results show that, compared with the method using dedicated channels to transfer data to the fusion center, the occurrence of the discrepancy between the global decisions of the two methods is less than 30 per a million tests. The increased amount of transmitted data, however, is not more than 5%, and the channel bandwidth of the system is reduced to of the original. Therefore, the proposed method fulfills the evident decrease in communication bandwidth, at a very small cost of detection performance.

Autocrine/Paracrine Function of Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) for Glucose Homeostasis in Pancreatic β-Cells and Adipocytes

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a second messenger for mobilizing Ca(2+) from intracellular stores in various cell types. Extracellular application of NAADP has been shown to elicit intracellular Ca(2+) signals, indicating that it is readily transported into cells. However, little is known about the functional role of this NAADP uptake system. Here, we show that NAADP is effectively transported into selected cell types involved in glucose homeostasis, such as adipocytes and pancreatic β-cells, but not the acinar cells, in a high glucose-dependent manner. NAADP uptake was inhibitable by Ned-19, a NAADP mimic; dipyridamole, a nucleoside inhibitor; or NaN3, a metabolic inhibitor or under Ca(2+)-free conditions. Furthermore, NAADP was found to be released from pancreatic islets upon stimulation by high glucose. Consistently, administration of NAADP to type 2 diabetic mice improved glucose tolerance. We propose that NAADP is functioning as an autocrine/paracrine hormone important in glucose homeostasis. NAADP is thus a potential antidiabetic agent with therapeutic relevance.

New Introduction: Search Method for Similar Images from Representative Video Frame Images

With rapid advances in computer and communications technology, the internet and video information is being used in a variety of areas?and the amount of this information is increasing exponentially. However, existing information analysis systems mainly depend on text, so it is not easy to differentiate video information. In order to solve this problem, we propose an algorithm that efficiently analyzes large amounts of video information and searches for similar images. We extract representative frames from a video via histogram analysis of the video information through low computational complexity of frame intervals. Then, we search for images with high similarity using information about colors and shapes. For obtaining color feature information in images and shape feature information, we use both hue?saturation?intensity and moment invariants.

A 2.4kb/s Speech Coder with Improved Analysis and Synthesis Based on MELP

This paper describes a speech coder which has an input signal frame interval of 20ms percent in duration, contains 160 voice samples (8,000 samples/s) and 48 bits. A key feature of the coder is a novel Line Spectral Frequencies (LSF) quantization scheme, requiring only 19 bits per frame. This new coder, through algorithmic improvements, enhanced quantization techniques and new harmonic synthesis method, produces better speech quality at 2.4 kb/s transnission rate than the new U.S. Federal Standard MELP coder.

Extraction and Recognition Chinese Character of Video Using Wavelet-fractal and Multilevel Classification

Extraction and recognition Chinese characters in a video are widely applied to fields like image annotation and retrieval. In this paper, we extract features of Chinese character based on wavelet-fractal and employ multi-level classification including K-means and Back Propagation Neural Network (BPNN) to recognize. we take the projection of image in 0 ◦ ,4 5 ◦ ,9 0 ◦ , 135 ◦ and ring as features. To verify the algorithm, we developed an extraction and recognition Chinese character system consists of text regions detection, tracking, character segmentation, and character recognition module. In the character tracking, by introducing the concepts of density, sliding window and similarity, we design an algorithm of back-searching and forward-searching the frame interval which includes specific text regions. Statistical hypothesis test is employed to segment the characters. Finally, we give full and detailed experiments according to the algorithms proposed in this paper and the results turn out these algorithms are efficient.

超高速高性能门控型三分幅相机

Aiming at the framing photography frequency of about 108 frame/s or above,a kind of 3-frame framing camera with ultra high-speed and high performance is developed and put into operation.The optical principle of the camera is based on splitting the focused imaging light beam in the field of image space.It features good imaging quality and high light energy efficiency.The lens coupled gated image intensifier with high speed shutter control ability,cooled scientific CCD camera and the high speed controller based on large scale field programmable gate array with system trigger and shutter trigger are the main portions.This framing camera can capture 3frame images with ultrahigh speed of above 3.3×108 frame/s.The minimum exposure time for each image is about 3ns and can be independently setup in a wide range of from several ns to s.The frame interval time can also be adjusted at discretion step from 0ns to second level.The effective image size isΦ25mm and image array is 1 024×1 024.The spatial resolution is about 30lp/mm.The framing camera features good linearity,good response uniformity,and excellent flexibility in applications.

Volumetric Characterization of Human Coronary Calcification by Frequency-Domain Optical Coherence Tomography

Coronary artery calcification (CAC) presents unique challenges for percutaneous coronary intervention. Calcium appears as a signal-poor region with well-defined borders by frequency-domain optical coherence tomography (FD-OCT). The objective of this study was to demonstrate the accuracy of intravascular FD-OCT to determine the distribution of CAC. Cadaveric coronary arteries were imaged using FD-OCT at 100-μm frame interval. Arteries were subsequently frozen, sectioned and imaged at 20-μm intervals using the Case Cryo-Imaging automated system(TM). Full volumetric co-registration between FD-OCT and cryo-imaging was performed. Calcium area, calcium-lumen distance (depth) and calcium angle were traced on every cross-section; volumetric quantification was performed offline. In total, 30 left anterior descending arteries were imaged: 13 vessels had a total of 55 plaques with calcification by cryo-imaging; FD-OCT identified 47 (85%) of these plaques. A total of 1,285 cryo-images were analyzed and compared with corresponding co-registered 257 FD-OCT images. Calcium distribution, represented by the mean depth and the mean calcium angle, was similar, with excellent correlation between FD-OCT and cryo-imaging respectively (mean depth: 0.25±0.09 vs. 0.26±0.12mm, P=0.742; R=0.90), (mean angle: 35.33±21.86° vs. 39.68±26.61°, P=0.207; R=0.90). Calcium volume was underestimated in large calcifications (3.11±2.14 vs. 4.58±3.39mm(3), P=0.001) in OCT vs. cryo respectively. Intravascular FD-OCT can accurately characterize CAC distribution. OCT can quantify absolute calcium volume, but may underestimate calcium burden in large plaques with poorly defined abluminal borders.

The complete mitochondrial genome and phylogenetic analysis of Nyctereutes procyonoides

The complete mitochondrial genome sequence of the raccoon dog (Nyctereutes procyonoides) was determined by using the long and accurate polymerase chain reaction. The entire mitochondrial genome sequence is 16,713bp in length contains two ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes and 1 control region. Most mitochondrial genes are encoded on the H strand, except for the ND6 gene and 8 tRNA genes. The base compositions of mitochondrial genomes present clearly A–T skew. All the transfer RNA genes can be folded into the typical cloverleaf-shaped structure except tRNA-Ser (AGY), which lacks the dihydrouridine arm. Protein-coding genes mainly initiate with ATG and terminate with TAA. Some reading frame intervals and overlaps are found in the mitochondrial genome. The control region can be divided into three domains: the extended termination associated sequences (ETASs) domain, the central conserved domain and the conserved sequence blocks (CSBs) domain. Three conserved sequence blocks (CSBs) and one extended termination associated sequences (ETAS-1) is found in the control region. The phylogenetic analysis based on the concatenated data set of 14 genes in the mitochondrial genome of Canidae shows that the raccoon dog has close phylogenetic position with the red fox (Vulpes vulpes) and they constitute a clade which has an equil evolutionary position with the clade formed by the genera Canis and Cuon.

Real-Time Optical Flow Estimation Using Multiple Frame-Straddling Intervals

In this paper, we propose a novel method for accurate optical flow estimation in real time for both high-speed and low-speed moving objects based on High-Frame-Rate (HFR) videos. We introduce a multiframe-straddling function to select several pairs of images with different frame intervals from an HFR image sequence even when the estimated optical flow is required to output at standard video rates (NTSC at 30 fps and PAL at 25 fps). The multiframestraddling function can remarkably improve the measurable range of velocities in optical flow estimation without heavy computation by adaptively selecting a small frame interval for high-speed objects and a large frame interval for low-speed objects. On the basis of the relationship between the frame intervals and the accuracies of the optical flows estimated by the Lucas–Kanade method, we devise a method to determine multiple frame intervals in optical flow estimation and select an optimal frame interval from these intervals according to the amplitude of the estimated optical flow. Our method was implemented using software on a high-speed vision platform, IDP Express. The estimated optical flows were accurately outputted at intervals of 40 ms in real time by using three pairs of 512×512 images; these images were selected by frame-straddling a 2000-fps video with intervals of 0.5, 1.5, and 5 ms. Several experiments were performed for high-speed movements to verify that our method can remarkably improve the measurable range of velocities in optical flow estimation, compared to optical flows estimated for 25-fps videos with the Lucas–Kanade method.

A Frame Rate Optimization Framework for Improving Continuity in Video Streaming

This paper aims to reduce the prebuffering requirements, while maintaining continuity, for video streaming. Current approaches do this by making use of adaptive media playout (AMP) to reduce the playout rate. However, this introduces playout distortion to the viewers and increases the viewing latency. We approach this by proposing a frame rate optimization framework that adjusts both the encoder frame generation rate and the decoder playout frame rate. Firstly, we model this problem as the joint adjustment of the encoder frame generation interval and the decoder playout frame interval. This model is used with a discontinuity penalty virtual buffer to track the accumulated difference between the receiving frame interval and the playout frame interval. We then apply Lyapunov optimization to the model to systematically derive a pair of decoupled optimization policies. We show that the occupancy of the discontinuity penalty virtual buffer is correlated to the video discontinuity and that this framework produces a very low playout distortion in addition to a significant reduction in the prebuffering requirements compared to existing approaches. Secondly, we introduced a delay constraint into the framework by using a delay accumulator virtual buffer. Simulation results show that the delay constrained framework provides a superior tradeoff between the video quality and the delay introduced compared to the existing approach. Finally, we analyzed the impact of delayed feedback between the receiver and the sender on the optimization policies. We show that the delayed feedbacks have a minimal impact on the optimization policies.

A simple and compact design for multi-chromatic channel digital holography to record femtosecond order processes

This paper proposes a simple and compact design for sequential imaging of a femtosecond order ultrafast process (10−12–10−13 s) with single-shot multi-chromatic channel digital holography, with temporal resolution of about 180 fs, without the need of complicated multi-beam alignments. In our numerical simulation, the sequential imaging recorded by a single CMOS camera is realized by four holograms corresponding to four different moments of the process and four chromatic channels of our special band-pass filter. The frame interval and temporal resolution of the imaging are determined by both the spectral separations and bandwidths of the channels in the filter, and the group velocity dispersion induced by a dispersive element.

PTES: A New Packet Transmission Technique in Bufferless Slotted OPS Networks

Optical packet contention is the major problem in optical packet switching (OPS) networks. In this paper, a software-based contention reduction scheme is proposed for all-optical multi-fiber slotted OPS networks, called packet transmission based on the scheduling of empty time-slots (PTES), suitable for overlaid star topology used in a metropolitan area with heterogeneous distances. In the scheduling procedure (performed in a distributed manner by each edge node of a star network) within a frame interval, some time-slots are scheduled as empty time-slots and the remaining time-slots are scheduled as non-empty. Then, an edge node must avoid sending its traffic in empty time-slots. Instead, non-empty time-slots can be used for traffic transmission. With respect to this scheduling, the variance of the number of non-empty time-slots that carry traffic from all edge nodes is minimized in the core node at each time-slot, thus reducing the traffic loss. Mathematical formulas are also provided to compute the traffic loss and delay under PTES. Performance evaluation results illustrate that PTES can reduce the number of collision events and traffic loss, especially at light and moderate traffic loads.

An Improved Difference Method Based on Three Asymmetric Frames and its Applications in the Vehicle Detection

Original difference method based on three sequential frames is a common method in the moving objective detection. After the introduction of the original method, the formation cause of the internal cavity in vehicle region was analyzed. Then, an improved difference method based on three asymmetric frames, which were abstracted according to the judgment rule of optimal frame interval, has been proposed in this paper. The area of the moving vehicle region is assumed as the criterion to calculate the best frame interval. In the improved method, the best benchmark frame and the best auxiliary frame were firstly abstracted out and used to subtract the current frame separately. Subsequently, the two difference images were transformed to binary images separately. Lastly, the final moving vehicles were detected in the current frame after logical "and" operation was carried out between the two binary images. The experimental results showed that the improve difference method based on three asymmetric frames can effectively reduce the internal cavities in the vehicle region, comparing with the original one.

Menstrual health: the unmet needs of adolescent girls in Sokoto, Nigeria

The perception and appropriate hygiene practices of girls towards menstruation is closely linked with their level of knowledge and beliefs. This study aimed to assess the level of knowledge on menstruation and hygienic practices among adolescent school girls in an urban city, Nigeria. The study was a cross sectional survey and a total 122 girls from 4 out of the 9 schools’ were recruited using a multistage sampling technique to select the schools, and systematic sampling method proportionate to size (proportion of total study unit accounted by each school) after a random selection of the first respondent, using the list of students as the sampling frame and sampling interval of 30. Overall, a total of 79 (65%) of the respondents had high knowledge. 15% of respondents’ indicated their major source of information on menstruation from their school teachers. There is a significant gap in knowledge and with minimal role played by the school environment to provide appropriate information during their formative years. The ages of the respondents (P = 0.93), education of their mothers (P = 0.173) and the sources of information regarding menstruation (P = 0.575) were found not to be statistically significant with respect to the knowledge of menstruation while there was a statistically significant relationship between religion (P = 0.0001) and level of study of the girls and knowledge of menstruation (P = 0.048) Concerning the practice of menstrual hygiene, the majority 106 (87%) of the girls used sanitary pads, only. There was a significant statistically association between education of their mothers (P = 0.015), religion (P = 0.0001) and occupation of respondents mother (P = 0.0028) with respect to the reported menstrual hygiene practices. Hence the need for targeted systematic information to adolescent through curriculum reviews towards better knowledge and practice of menstrual hygiene. Key words: Menstruation, adolescence, secondary school, menstrual hygiene.