Error concealment using layer structure for JPEG2000 images

In this paper, a prescription-based error concealment (PEC) method is proposed. PEC relies on pre-analyses of the concealment error image (CEI) for I-frames and the optimal error concealment scheme for P-frames at encoder side. CEI is used to enhance the image quality at decoder side after error concealment (by spatial interpolation or zero motion) of the corrupted intra-coded MBs. A set of pre-selected error concealment methods is evaluated for each corrupted inter-coded MB to determine the optimal one for the decoder. Both the CEI and the scheme indices are considered as the prescriptions for decoder and transmitted along with the video bit stream based on a reversible data embedding technique. Experiments show that the proposed method is capable of achieving PSNR improvement of up to 1.48 dB, at a considerable bit-rate, when the packet loss rate is 20%

Solubility of magnesium hydrogen l-aspartate was examined. This salt is very easily soluble in water but hardly dissolves in organic solvents. In a mixture of water and organic solvents miscible with water, such as methanol, ethanol, propanol, and acetone, the salt distributes between the two layers, forming a dilute solution of the salt in the upper layer and a concentrated solution in the lower layer. The solubility of the slat in the upper layer increases exponentially with the molar fraction of water in the upper layer and the solubility is not affected by temperature. Analysis was carried out on the propanol-water-aspartate system in the upper and lower layers, three-componental phase diagram was prepared, and the Plait point, at which the upper and lower layers agreed, was calculated. It was also found that the exponential function established between the solubility in the upper layer and molar fraction of water thereof is also applicable to the lower layer.

On days with clear skies in late August 2002 diurnal changes in the within-branch heterogeneity of photosynthetic photon flux density at the leaf surface (PPFDs) and leaf temperature (T leaf) were measured at natural leaf orientations in the upper and lower layers of a Fagus crenata crown. The PPFDs and T leaf measurements were converted to branch photosynthesis rates (P B; μmol s−1) using a photosynthetic model proposed by Farquhar et al. (Planta 149:78–90, 1980), an empirical stomatal conductance model suggested by Leuning et al. (Plant Cell Environ 18:339–335, 1995), and the total leaf area of the branches. To evaluate the importance of the variation in PPFDs and T leaf on photosynthesis calculations, P B calculated with the observed variation in PPFDs and T leaf was compared with estimates, based on the average (variation-free) values of PPFDs and T leaf, respectively. In both the layers, daily total P B values obtained with T leaf averaging were very close to those obtained with no averaging because of the weak inflection of the net photosynthesis rate (P n) to T leaf curves in the observed T leaf ranges (24.4–36.5 and 21.9–29.1°C in the upper and lower layers, respectively) and relatively small variation in within-branch T leaf at each time of day. This finding applied across potential climate conditions on fine days in August (T leaf range of 19.4–41.5 and 16.9–34.1°C in the upper and lower layers, respectively) and when the spatial scale was increased from branch to leaf layer, which increased the maximum variation in within-branch T leaf from 7.8 to 9.5°C and 4.5 to 5.5°C in the upper and lower layers, respectively. In contrast, averaging PPFDs caused 25–50% and 41–90% overestimation of daily total P B in the upper and lower layers, respectively, due to the sharp curvature in the PPFDs response curve to P n, and relatively large variation in within-branch PPFDs. Further, it led to overestimation of midday depression of P B in the upper layer, possibly because branch structural acclimation to incident light was neglected. Our results indicate that averaged values of T leaf could be used for the estimation of carbon gain at layer scale throughout August, but spatial variations in PPFDs need to be considered in detail for reliable estimates of carbon gain.

Toner charge distributions in corona charged toner layers on a grounded metal plate were investigated. The charge distributions were measured through image analysis of the toner particles displaced onto a filter, depending on their charge to diameter ratio, after being blown off from the toner inlet into an electric field and dispersed. It has been confirmed that the toner charge distributions became broader by corona charging. In order to clarify the cause, dual toner layers have been formed by using different color toners, and the charge distributions at the upper and lower layers have been measured separately. The results show that the lower toner layer has a wider charge distribution than that of the upper layer. This result is attributable to the fact that the lower parts of the toner layer are covered with the upper toner layer and difficult to corona charge. The toner particles in the lower layer located at the opening of the overlapped upper layer tend to be highly corona charged, while the toner particles around the opening in the upper layer receive only a small amount of the corona charge. It has thus been shown that difference in charge distribution between the upper and lower parts of the toner layer is caused by the following mechanisms: 1) The toner particles at the lower part of the layer are shielded from corona charging ions by the upper layer; 2) The toner particles in the lower layer, which are located at the opening of the charged particles in the upper layer, receive more charging ions by concentration of the electric field; 3) The toner particles at the upper layer receive fewer charging ions because of higher electric potential owing to a longer distance from the grounded plate.

A two‐layer model with a rigid lid and a flat bottom on an f plane is employed to study a flow field driven by a density flux through the sea surface or the coast; for example, freshwater discharged from a river. The negative (positive) density flux into the upper layer is represented by the water beneath (over) the interface changing from the lower (upper) layer to the upper (lower) layer, that is, entrainment of the lower (upper) layer by the upper (lower) layer. The subinertial flow pattern constrained by the coast has two components: one is a baroclinic eddy nearby that matches the entrainment region, and the other is a forced, internal Kelvin wave along the appropriate half of the coast.

Levels of type VI collagen mRNAs were determined in cultured skin fibroblasts derived from the upper, middle, and lower layers. The level of alpha 1 (VI) collagen mRNA was the highest in the fibroblasts from the upper layer. In contrast, alpha 2 (VI) collagen mRNA level in the fibroblasts from the lower layer predominated over those in the upper and middle layers. The level of alpha 3 (VI) collagen mRNA was the same in the three dermal layers. When the fibroblasts from the upper layer were passaged successively, the alpha 1 (VI) collagen mRNA level declined and alpha 2 (VI) collagen mRNA level increased to those of the lower dermal fibroblasts. These results indicate that alpha 1 (VI) and alpha 2 (VI) collagen expressions in skin fibroblast cultures are heterogeneous and that successive passages of the upper dermal fibroblasts may result in transition of the phenotype of alpha 1 (VI) and alpha 2 (VI) expression to that of lower dermal fibroblasts. The modulation of the expression of alpha 1 (VI) and alpha 2 (VI) chains presumably reflects the process of cellular aging in vitro and should be a useful biochemical marker in studies of cell aging.

Early visual experience is essential for the maturation of visual functions in which the primary visual cortex plays crucial roles. The extraction of visual features based on response selectivity of individual neurons, a fundamental process in the cortex, is basically established by eye opening in rodents, suggesting that visual experience is required for the development of neural functions other than feature extraction. Here, we show that synchronized firing, which is important for visual information processing, occurs selectively in adjacent neurons sharing similar orientation or spatial frequency preferences in layers 2-4 (upper layer) of rat visual cortex. This feature-selective spike synchrony was rudimentary when the eyes opened and became prominent during the first few weeks after eye opening only in the presence of pattern vision. In contrast, synchronization in layers 5-6 (lower layer) was almost independent of orientation similarity and more weakly dependent on spatial frequency similarity compared with upper layer synchrony. Lower layer synchronization was strengthened during development after eye opening independently of visual experience as a whole. However, the feature selectivity of synchronization was regulated by visual inputs, whereas the inputs without contours were sufficient for this regulation. Therefore, we speculate that feature-selective synchronization in the upper layer may convey detailed information on visual objects to the higher-order cortex, whereas weakly feature-selective synchronization in the lower layer may covey rather rough visual information to the subcortical areas or higher-order cortex. A major role of visual experience may be to establish the specific neural circuits underlying highly feature-selective synchronization.SIGNIFICANCE STATEMENT The neuronal mechanisms underlying experience-dependent improvement of visual functions still remain unresolved. In this study, we investigated whether early visual experience contributes to the development of synchronized neural firing in the primary visual cortex, which plays important roles in visual information processing. We found that synchronized firing depends more remarkably on the similarity of preferred visual stimuli in the upper than lower layer neurons. Pattern vision during development was required for the establishment of spike synchrony in the upper but not the lower layer. These findings provide a new view regarding the role of sensory experience in the functional development of the cortex and the differences in the modes of information processing in the upper and lower cortical layers.

This paper presents an electroactive and soft vibrotactile actuator based on a dielectric elastomer. The vibrotactile actuator is composed of an upper layer, an adhesive tape layer, a dielectric layer with bumps, and a lower layer. When a voltage is applied to the actuator, an electrostatic force created between the upper and lower layers pulls the upper layer down, compressing the dielectric layer. As soon as the applied voltage is released, the upper layer is quickly restored to its initial state by the elastic force of the compressed dielectric elastomer. Because two forces contribute to the actuation at the same time, the created vibration is sufficiently strong to stimulate human mechanoreceptors. When the applied voltage is removed, the upper layer and dielectric elastomer return to their initial shapes. We conducted experiments to determine the best weight ratio of polydimethylsiloxane (PDMS) and Ecoflex, and to quantitatively investigate the haptic performance of the proposed vibrotactile actuator. The experiments clearly show that the plasticized vibrotactile actuator can create a variety of haptic sensations over a wide frequency range.

Abstract: Stratification is an important phenomenon in natural forests. The mixed pine-oak forests along the Nanpan River in southwest China was clearly formed by two layers in the vertical direction. These forests developed in an area where the virgin forests suffered clear-cutting. After excluding habitat heterogeneity, we divided two plots into upper and lower layers according to the tree height, and then analyzed the spatial pattern, species distribution, and size differentiation using the pair correlation function g(r) and the mark correlation function (MCF) kmm (r), respectively. The following key results were obtained: (1) the upstory was slightly clustered, whereas the understory had an intensively clumped pattern. An uneven pattern of germplasm resources in the early stages of succession and seed dispersion limitation may have contributed to the aggregation of tree species. (2) The spatial correlation among the main populations in each layer, and between both layers, had a largely random association, suggesting that differences in tree growth and physiological characteristics play an important role in species association. (3) Species aggregation decreased as the observation scale increased; however, the aggregation intensity of the understory was significantly higher than that of the upstory, which may be related to negative density dependence and niche complementarity. (4) Size differentiation in the upstory was significant, with small trees gathered together. There were no obvious differences in tree size in the lower layer, indicating a higher competitive pressure among trees in the upper layer. In conclusion, the spatial structure of trees in terms of vertical stratification differs, which is of great significance for investigating the mechanisms by which species coexist.

Error concealment is a well-known technique to improve reproduced picture quality in cases which parts of the coded picture are not available at a decoder for reconstruction. The conventional error concealment methods generally make use of the correlation between a damaged marcoblock and its adjacent macroblocks in the same frame and/or the previous frame. However, performance results of concealment methods are different each other and dependent on how much damaged frames and macroblocks are correlated to surrounding ones temporally and spatially. Moreover, most of them can not conceal effectively the consecutively damaged frames or macro blocks caused by wireless bursty packet loss features, since motion vectors and correlation information between the damaged images are already destroyed. The proposed error concealment aware error resilient video coding is a new method which has an intelligent error concealment selector by using pre-estimation technique of the possibly damaged motion vectors at the encoder. The method recommends the best error concealment per macroblock by transmitting additionally its error concealment selection codes to the decoder. The chosen error concealment helps to conceal the damaged MB at the decoder even when losses of frames are bursty. The experimental results show the substantial effectiveness to improve video quality at the cost of a little bit overhead at the transmitted bit streams.

<p>Anisotropy in the Earth’s upper mantle is a signature of past and present deformation. Sri Lanka comprises four main lithological units, viz. the Highland Complex (HC), the Wanni Complex (WC), the Vijayan complex (VC) and the Kadugannawa complex (KC). To calculate the upper mantle anisotropy, we have collected the earthquake data from IRIS (Incorporated Research Institutions for Seismology) network. The upper mantle anisotropy beneath Sri Lanka is measured in the frequency band 0.01–0.15 Hz, with magnitude (Mw) of six or more and within the epicentral distance of 90°-140°. We have analyzed (the fast direction and delay time) shear wave splitting of SKS/SKKS phases at 3 stations, namely, MALK (WC), HALK (HC) and PALK (KC) in Sri Lanka. In this study, shear wave splitting measurements were done using high-quality seismograms (~30) of many earthquakes occurring in the region. We have used rotational correlation (RC) , minimum energy (SC) and eigenvalue techniques. The result of the shear-wave splitting measurement shows the presence of two anisotropic layers in the upper mantle. The upper and lower layer’s fast-polarization direction is found to be NE-SW and NW-SE, has the delay time varies from 0.4-0.5s in the upper layer, and 0.6-0.8s in the lower layer. We found two major fast directions in the upper and lower layers, viz. NE-SW in the upper layer of MALK and PALK and NW-SE for the HALK stations, and NNE-SSW in the lower layer beneath MALK and HALK stations and NW-SE in the PALK station. Overall, Fast direction for Sri Lanka region is found to be NE-SW in the lower layer and NW-SE in the upper layer. Our study suggests that fast axis direction of lower layer with an average delay time of 0.6 s depicts a ~67 km thick anisotropic layer with 4% anisotropy (from previous studies) beneath Sri Lanka region. However, if we assume an anisotropy range of 3–5%, then the calculated delay time of 0.6 s would correspond to thickness variation of 89.3 to 53.59 km, respectively, for the inferred anisotropic layer. Comparing from APM (Absolute Plate Motion) direction with our fast directions, we infer that the SAF(Simple Asthenospheric Flow) model prevails in this region and secondly, when S<sub>hmax </sub>(Maximum Horizontal stress) and the GPS (Global Positioning System) data compared with the fast direction we infer that there is partial contribution from lithospheric mantle. So, we confirmed that anisotropy in the region is mainly governed by asthenospheric flow and partially due to lithospheric mantle.</p>

Priming effect is one of the important mechanisms regulating soil organic matter decomposition. However, the variation of priming effects in different soil layers remains unclear. In this study, we conducted a 30-day incubation experiment using no-tillage black soil from northeastern China. 13C-glucose and dynamic CO2 trapping methods were employed to investigate soil organic carbon (SOC) mineralization rates and the priming effect of the added 13C-glucose in the upper soil layer (0-10 cm) and the lower soil layer (30-40 cm). Our results showed that the cumulative SOC-specific mineralization rate in the upper layer was similar to that in the lower layer soil without glucose addition. Glucose addition significantly altered the mineralization rates in both layers, resulting in a positive priming effect (36.7%) in the upper layer but a negative priming effect (-12.4%) in the lower layer. The cumulative priming effect during the 30-day incubation was 3.24 mg C·g-1 SOC for the upper layer soil and -1.24 mg C·g-1 SOC for the lower layer soil. There was still a net SOC increase, even with positive priming effects in the upper layer soil. This was due to considerable amount of added glucose-C remained un-mineralized in the soil which would compensate the carbon loss from priming effects. Overall, our results demonstrated that the magnitude and direction of priming effects might differ between soil layers. Our findings contribute to a better understanding of the effects of conservation tillage practices (no-tillage and straw incorporation) on soil organic matter dynamics in agroecosystems.

We have succeeded in generating B cell colonies from freshly separated human peripheral blood by the double agar layer technique and expanding them in liquid culture for several weeks. Populations of cells enriched in B cells were placed into the upper layer with or without bacterial LPS. Although B cell colonies were observed without LPS, the addition of LPS to the cells in the upper agar layer increased the number of colonies. Also necessary for optimal B cell colony formation was the presence in the lower agar layer of either culture supernatant of PHA-stimulated mononuclear cells or purified T cells and PHA. Without such helper factors in the lower layer, only a few B cell colonies were observed in the upper layer. By using these techniques, peripheral blood lymphocytes from normal individuals and patients with active systemic lupus erythematosus (SLE) were studied for the generation of B cell colonies. Significantly more B cell colonies were observed in patients with SLE, using either kind of "helper" factor. In addition, T cells from normal individuals and patients were tested for their ability to help B cell colony formation. The SLE T cells were found to be defective in this function relative to normal T cells. Thus, although patients with SLE were hyperactive in forming B cell colonies, thier T cells were defective in supporting the formation of B cell colonies from normal individuals.

The air pressures in coastal unsaturated zones fluctuate in response to tidal fluctuations. Two‐phase air‐water flow induced by sea tides in a coastal two‐layered subsurface system is investigated through numerical simulations. The system consists of upper and lower layers with permeabilities of kU and kL, respectively. A water table exists in the lower layer. The study demonstrates that airflow in the unsaturated zone is controlled by permeabilities of both layers and the fluctuation of water level. The tide‐induced water level fluctuation may result in significant air pressure fluctuation in the unsaturated zone in an air‐confined system; that is, the permeability of the upper layer is about 2 orders of magnitude lower than that of the lower layer. In such an air‐confined system, horizontal airflow is dominant in the lower layer and vertical airflow is dominant in the upper layer. The simulation results show that the hydraulic head, rather than the sea tide, is the direct driving force of the air pressure fluctuation above the water table. The study on the relation between the air pressure amplitude and the landward distance demonstrates that the air pressure amplitudes increase to a maximum and then decrease with distance. The amplitude of air pressure fluctuation decreases progressively with kU in the lower layer. In the upper layer, however, the amplitude tends to increase with kU when kU is very low and decrease with kU when kU is relatively high. Overall, the air flux fluctuations across the atmosphere‐soil interface attenuate landward gradually, and this attenuation becomes faster as the permeability of the upper layer increases.

Expressions for the drain flow, the surface inflow distribution , and flow nets are derived for surface water seeping into drain tubes embedded in water‐saturated soil consisting of two horizontal strata of different permeabilities. In Part I, the drain tubes are located in the upper layer. Numerical results are presented. It is shown in the case of the flow nets how Kennelly's tables of the complex hyperbolic sine may be used to obtain numerical values for equipotentials and stream lines simultaneously. The flow nets, as well as other results, show that unless the lower layer is of high permeability compared to the upper layer, the lower layer has little effect on the flow.In Part II, the drain tubes are located in the lower layer which extends to great depth. It is shown that, unless the drain tubes are very near the upper layer, or unless the upper and lower layers are of approximately the same permeability, fee lower layer governs the flow. Quantitative results are worked out for several cases, including a flow net. The mathematical analysis in both cases is presented in some detail. This is done so that the reader will be able to work out certain details readily for himself. But the material is presented in such a way that readers not desiring to follow mathematical details may, without loss of continuity, skip all but the first few paragraphs of the Analysis and proceed to Results and Discussion.