Dynamic clipping ratio determination for global backlight dimming in LCD

BACKGROUND AND AIMS Chronic kidney disease-associated pruritus (CKD-aP) is a common condition in patients with CKD undergoing haemodialysis (HD), leading to poor sleep quality, reduced quality of life and depression. Difelikefalin is a selective kappa opioid receptor agonist approved in the United States for the treatment of moderate-to-severe pruritus in adults undergoing HD, which significantly reduced itch intensity in HD patients with CKD-aP in the Phase 3 KALM-1 and KALM-2 multicentre, placebo-controlled trials. The KALM trials used the Worst-Itching Numerical Rating Scale (WI-NRS) to assess itch-intensity [range from 0 (no itching) to 10 (worst itching imaginable)] and the Patient Global Impression of Change (PGIC) to assess the patient's overall perception of change in itch (range from ‘very much improved’ to ‘very much worse’) relative to the start of the study. The aim of this post hoc analysis was to establish how the WI-NRS score relates to the PGIC and to assess a clinically relevant change in WI-NRS. METHOD A post hoc analysis of data from KALM-1 and KALM-2 was performed. Studies enrolled maintenance HD patients with mean baseline 24-h WI-NRS score > 4 in KALM-1 or ≥ 5 in KALM-2. Patients were randomized 1:1 to intravenous difelikefalin 0.5 mcg/kg or placebo three times/week for 12 weeks. Patients completed the PGIC at the end of the 12-week, double-blind treatment period, as well as completing the WI-NRS daily. Cumulative distribution function (CDF) analyses were performed at Week 12. Results are reported for 50% CDF at week 12. RESULTS For the overall population, ‘very much improved’ corresponded to a 5-to-6-point WI-NRS reduction; ‘much improved’ corresponded to a 3-to-4-point WI-NRS reduction; and ‘minimally improved’ corresponded to a 1-to-2-point WI-NRS reduction (Figure 1). CONCLUSION There is a clear relationship between the PGIC and the WI-NRS, with greater reductions in itch severity corresponding to perceptions of better overall improvement in itch following treatment with difelikefalin. A 3-point reduction in WI-NRS can be considered clinically relevant, since it was perceived by patients as equivalent to their itch being ‘much improved’. This analysis further corroborates similar clinically meaningful changes in pruritus, previously reported in patients with CKD-aP, as ≥ 3-points [1, 2].

Liquid crystal displays (LCDs) have appeared in applications ranging from medical equipment to automobiles, gas pumps, laptops, and handheld portable computers. These display components present a cascaded energy attenuator to the battery of the handheld device which is responsible for about half of the energy drain at maximum display intensity. As such, the display components become the main focus of every effort for maximization of embedded system's battery lifetime. This paper proposes an approach for pixel transformation of the displayed image to increase the potential energy saving of the backlight scaling method. The proposed approach takes advantage of human visual system (HVS) characteristics and tries to minimize distortion between the perceived brightness values of the individual pixels in the original image and those of the backlight-scaled image. This is in contrast to previous backlight scaling approaches which simply match the luminance values of the individual pixels in the original and backlight-scaled images. Furthermore, this paper proposes a temporally-aware backlight scaling technique for video streams. The goal is to maximize energy saving in the display system by means of dynamic backlight dimming subject to a video distortion tolerance. The video distortion comprises of: 1) an intra-frame (spatial) distortion component due to frame-sensitive backlight scaling and transmittance function tuning and 2) an inter-frame (temporal) distortion component due to large-step backlight dimming across frames modulated by the psychophysical characteristics of the human visual system. The proposed backlight scaling technique is capable of efficiently computing the flickering effect online and subsequently using a measure of the temporal distortion to appropriately adjust the slack on the intra-frame spatial distortion, thereby, achieving a good balance between the two sources of distortion while maximizing the backlight dimming-driven energy saving in the display system and meeting an overall video quality figure of merit. The proposed dynamic backlight scaling approach is amenable to highly efficient hardware realization and has been implemented on the Apollo Testbed II. Actual current measurements demonstrate the effectiveness of proposed technique compared to the previous backlight dimming techniques, which have ignored the temporal distortion effect

Nonlinear evolution of the cosmological background density field as diagnostic of the cosmological reionization

In this paper, the problem of security in multiple input multiple output (MIMO) system has been analysed in the presence of an eavesdropper in cognitive radio networks. Multiple primary and secondary users communicate with the primary and secondary receiver, respectively. The secrecy capacity at primary receiver (PR) and secondary receiver (SR) have been calculated. At first, we use zero-forcing (ZF) precoding at the relay which enhances the secrecy capacity of PR and SR by nullifying the impact of interference. Secondly, we use a scheme to improve the secrecy capacity of the PR and SR using the existing interference energy of the communication medium employing selective precoding (SP) at the relay. Finally, we employ phase alignment precoding (PAP) for further increase in the secrecy capacity for PR and SR by using the destructive part of interference. Our analysis shows that among the three precoding techniques, the best performance is achieved by using the PAP at the relay in terms of secrecy capacity, complementary cumulative distribution function (CCDF) and outage probability analysis.

One of the key performance measures of cloud computing systems is the response time. However, the mean value of this characteristic does not give the full picture of quality of service. Therefore, we derive the cumulative distribution function (CDF) of the response time in terms of Laplace-Stieltjes transform and use it to evaluate moments of the response time. Moreover, we introduce a simplification of the mathematical model that significantly reduces computing complexity for the response time CDF and provide analysis of approximation accuracy of the simplified model.

A method to maximize backlight dimming of liquid crystal displays (LCDs) based on human visual system are proposed to minimize power consumption of display panels. Based on images, the proposed method optimizes global, local, and red, green, blue (RGB) backlight dimming by enhancing dimming about 12% on average for various images while maintaining tolerable degradation of perceived image qualities in pixel saturation areas. The method considers and utilizes the brightness sensitivity and contrast response functions of human visual system using the mean luminance and the contrast of an image, which are mathematically modelled to allow optimization for display panels and application areas. A simulator that can calculate various dimming cases with the evaluations of numerical and perceptual image qualities as well as power consumption amount is introduced. With pattern and real photo images, the degree of power savings and the preservation of image quality of the proposed method are verified to outperform conventional approaches with high scores of the mean opinion score (MOS) and the structural similarity index measure (SSIM) over 0.97 while saving more than 10% of power dissipation.

Liquid Crystal Display (LCDs) with Light Emitting Diode (LED) backlight is a very popular display technology, used for instance in television sets, monitors and mobile phones. This paper presents a new backlight dimming algorithm that exploits the characteristics of the target image, such as the local histograms and the average pixel intensity of each backlight segment, to reduce the power consumption of the backlight and enhance image quality. The local histogram of the pixels within each backlight segment is calculated and, based on this average, an adaptive quantile value is extracted. A classification into three classes based on the average luminance value is performed and, depending on the image luminance class, the extracted information on the local histogram determines the corresponding backlight value. The proposed method has been applied on two modeled screens: one with a high resolution direct-lit backlight, and the other screen with 16 edge-lit backlight segments placed in two columns and eight rows. We have compared the proposed algorithm against several known backlight dimming algorithms by simulations; and the results show that the proposed algorithm provides better trade-off between power consumption and image quality preservation than the other algorithms representing the state of the art among feature based backlight algorithms.

The problem of improving the efficiency of contrast enhancement for complex low-contrast images in an automatic mode with an acceptable level of computational costs is considered. A new approach to image enhancement by parameter-free intensity transformation based on an estimate of the bivariate distribution of brightness is proposed. Analysis of the bivariate distribution of brightness enables to significantly improve the efficiency of image contrast enhancement. Based on this approach, a new generalized description for the procedure of intensity transformation based on the analysis of the marginal cumulative distribution function of image brightness is proposed. The relationship between the proposed generalized description of the intensity transformation and the traditional definition of histogram equalization is shown. Based on proposed description, a new technique of modified histogram equalization is proposed. The research confirms the effectiveness of the proposed technique. The proposed technique of modified histogram equalization provides an increase in the efficiency of contrast enhancement compared to the well-known traditional technique of histogram equalization.

On the Chebyshev-Cramér Asymptotic Expansions

A variational determination of the hybrid coefficients in an spz harmonic hybrid model of the angular distribution shows that the pz mode maximizes at the liquid surface. Certain thermodynamic functions of the surface may be expressed in terms of the hybridization ratio of the coefficients.

Analysis of the experimental atomic radial distribution functions for thin amorphous films of zinc phosphides obtained by explosive laser sputtering has been performed within a fragmentary model. The experiment was carried out with an EMP-100A electron diffractometer in transmitted light at accelerating voltages of 50 and 75 kV. The films obtained by sputtering of β-ZnP2 single crystals contained nanoparticles of this phase. The films based on Zn3P2 turned out to be two-phase and consisted of dispersed Zn3P2 and β-ZnP2 nanoparticles. The composition of the film obtained on the basis of α-ZnP2 corresponded neither to any one of the known phases in the Zn-P system nor to any mixture of these phases. Crystallization of films in a divergent electron beam confirmed the results of the phase analysis performed using the model atomic radial distribution functions.

In fluorescent materials, light from a certain band of incident wavelengths is reradiated at longer wavelengths, i.e., with a reduced per-photon energy. While fluorescent materials are common in ev...

Analysis of carrier distribution function through Smith-Purcell effect in GaAs/GaAlAs heterostructures

Cellular automaton (CA)-based device simulation is one of the most powerful tool to solve Boltzmann transport equation (BTE) of carriers in semiconductor devices. In comparison to the Monte Carlo (MC) method which suffers statistical noise problems, cell representation used in the CA method realizes noise free analysis of the carrier distribution function (DF) both in real and momentum space. However, CA requires more computer resources than MC in typical cases because cell sizes used for both real and momentum space are restricted to be small enough not to cause artificial diffusion (ADF). In this paper, a new scheme for calculation of flux among cells is proposed in which carrier distribution is interpolated between neighbor cells. The suppression of ADF is confirmed through comparisons to other simulation methods in homogeneous cases, an n/sup +/-p diode case and an n/sup +/-n-n/sup +/ structure case. Consistency with MC analysis is also demonstrated by analyzes of homogeneous cases and an n/sup +/-n-n/sup +/ case and also by a theoretical study. A speed up of at least two orders of magnitude can be obtained by introducing the new flux calculation whose accuracy is ensured with much less number of cells than conventional CA methods. Consequently, this CA method is drastically improved as a practical tool for semiconductor device modeling from the point of CPU time and accuracy.

A model accounting for particle interaction with channel walls and collisions between particles is proposed on the basis of analysis of experimental particlevelocity distribution functions.