A Column-parallel Single-Slope ADC with Signal-Dependent Multiple Sampling Technique for CMOS Image Sensor

Department of Electrical EngineeringBoth Charge-Coupled Device (CCD) and Complementary Metal-Oxide Semiconductor (CMOS) image sensor have same starting point ??? they convert light photons into electrons. Recently, CMOS image sensor (CIS) has been developed significantly. CIS is much less expensive to manufacture than CCD sensor. Also, CIS has advantages over high speed, low noise and low power consumption. Therefore, such features can be used for many applications. In general, CIS has the number of incoming photons dependent noise characteristics. In the bright condition, photon shot noise is dominant in CIS compared with other noise sources. Photon shot noise cannot be reduced by circuit technique in single frame. However, CIS has high SNR in bright condition because the slope of the increase in signal is faster than the slope of increase in noise. But, in the dark condition, photon shot noise is not dominant in CIS. Random noises have dominance In CIS in the dark condition. These effects of noises can be reduced by circuit techniques. In the same way, Indirect Time-of-Flight (I-TOF) sensor has similar characteristics. When it measures long distance, its depth accuracy is reduced because of lack of incoming photons same as CIS in the dark condition. Therefore, same circuit technique can be used for pursuing beneficial effects on CIS and I- TOF sensor. To increase SNR in CIS, imposing gain in correlated double sampling stage as pre-amplifier. Therefore, it can increase SNR and reducing effects of readout random noises. However, it cannot increase gain highly as we want because of saturation problem and large power consumption. Therefore, it is not an advantageous method of low power systems. Otherwise, the multiple sampling technique had been proposed. It averages out all of the readout random noises by sampling several times [7]. Therefore, noise power is reduced in the inverse of sampling number and in voltage domain, noise rms value is reduced in the inverse of square root of sampling number. However, sampling several times increases readout time which is proportional to sampling number significantly. Therefore, to alleviate trade-offs coming from multiple sampling, several approaches is developed in the past. Typical examples are signal-dependent multiple sampling technique, pseudo multiple sampling technique and conditional multiple sampling technique. First, the pseudo multiple sampling technique decreases resolution of ADC for keeping conventional readout time [8]. Therefore, all of the pixels will be sampled several times, regardless of the value of those pixel values. Therefore, it has a limitation of effects of multiple sampling because of quantization noise due to large quantization step for achieving larger sampling number. Second, the signal dependent multiple sampling technique has been proposed [9]. It changes its 8sampling number according to pixel values. However, this concept can be achieved after operation of conventional readout. Therefore, it at least doubles readout time compared with conventional one. Finally, conditional multiple sampling technique has been proposed [10]. Similarly, the number of samplings is changed depending on the pixel value. However, it divides into two casesthe bright condition and the dark condition. Therefore, its boundary errors will be significant in output images. The proposed ADC can achieve conserving readout time with using multiple ramp generators. Also, it can change the sampling number according to pixel values gradually without sacrificing resolution of ADC [12]. It is composed with column-level digital logic for ramp selection and ripple local counter then size problem is not critical problem. Therefore, it can reduce boundary errors through the sample counter of the intermediate level. With this concept, adjusting the number of ramp generators, depending on the application, it can take the appropriate sampling number and reduces the power consumption consideration. Therefore, proposed ADC is new concept of signal-dependent multiple sampling technique with several ramp generators without sacrificing ramp resolution and readout time.clos

Domain-mediated interactions for protein subfamily identification

Within a protein family, proteins with the same domain often exhibit different cellular functions, despite the shared evolutionary history and molecular function of the domain. We hypothesized that domain-mediated interactions (DMIs) may categorize a protein family into subfamilies because the diversified functions of a single domain often depend on interacting partners of domains. Here we systematically identified DMI subfamilies, in which proteins share domains with DMI partners, as well as with various functional and physical interaction networks in individual species. In humans, DMI subfamily members are associated with similar diseases, including cancers, and are frequently co-associated with the same diseases. DMI information relates to the functional and evolutionary subdivisions of human kinases. In yeast, DMI subfamilies contain proteins with similar phenotypic outcomes from specific chemical treatments. Therefore, the systematic investigation here provides insights into the diverse functions of subfamilies derived from a protein family with a link-centric approach and suggests a useful resource for annotating the functions and phenotypic outcomes of proteins.11Ysciescopu

Design of a Time-of-Flight Sensor with Standard Pinned-Photodiode Devices Towards 100 MHz Modulation Frequency

We present an indirect Time-of-Flight (ToF) sensor based on standard pinned-photodiode (PPD) devices and design guides to pave the way for the development of a ToF pixel operating at 100 MHz modulation frequency. The standard PPDs are established well as predominant devices for 2-D color imagers in these days because of their low noise characteristic, but slow transfer speed of photo-generated electrons still prevents them from being employed to 3-D depth imagers. Optimized PPD structure with no process modifications is introduced to create a lateral electric field for enhancing charge transfer speed inside the PPD, and essential design parameters for achieving high operating frequency such as the epitaxial layer thickness, the pinning voltage, and the threshold voltage of the transfer gates are discussed with TCAD simulation results in this paper. Prototype indirect ToF sensors with various structures and parameters were fabricated using a 0.11-??m standard CIS process and characterized fully. We successfully evaluated the demodulation contrast of each pixel at 10 to 75 MHz frequencies, figuring out the suitable conditions of the PPD-based pixel. The best pixel operating at 50 MHz frequency demonstrated a depth resolution of less than 13 mm and a linearity error of about 3.7% between 1 and 3 m distance with a zeroorder calibration. We believe further optimization of the ToF pixel incorporated with the PPD devices is possible to improve the performance, operating it towards 100 MHz modulation frequency

Evolutionary coupling analysis identifies the impact of disease-associated variants at less-conserved sites

Genome-wide association studies have discovered a large number of genetic variants in human patients with the disease. Thus, predicting the impact of these variants is important for sorting disease-associated variants (DVs) from neutral variants. Current methods to predict the mutational impacts depend on evolutionary conservation at the mutation site, which is determined using homologous sequences and based on the assumption that variants at well-conserved sites have high impacts. However, many DVs at less-conserved but functionally important sites cannot be predicted by the current methods. Here, we present a method to find DVs at less-conserved sites by predicting the mutational impacts using evolutionary coupling analysis. Functionally important and evolutionarily coupled sites often have compensatory variants on cooperative sites to avoid loss of function. We found that our method identified known intolerant variants in a diverse group of proteins. Furthermore, at less-conserved sites, we identified DVs that were not identified using conservation-based methods. These newly identified DVs were frequently found at protein interaction interfaces, where species-specific mutations often alter interaction specificity. This work presents a means to identify less-conserved DVs and provides insight into the relationship between evolutionarily coupled sites and human DVs.11Ysciescopu

OASIS 2: online application for survival analysis 2 with features for the analysis of maximal lifespan and healthspan in aging research

Online application for survival analysis (OASIS) has served as a popular and convenient platform for the statistical analysis of various survival data, particularly in the field of aging research. With the recent advances in the fields of aging research that deal with complex survival data, we noticed a need for updates to the current version of OASIS. Here, we report OASIS 2 (http://sbi.postech.ac.kr/oasis2), which provides extended statistical tools for survival data and an enhanced user interface. In particular, OASIS 2 enables the statistical comparison of maximal lifespans, which is potentially useful for determining key factors that limit the lifespan of a population. Furthermore, OASIS 2 provides statistical and graphical tools that compare values in different conditions and times. That feature is useful for comparing age-associated changes in physiological activities, which can be used as indicators of "healthspan." We believe that OASIS 2 will serve as a standard platform for survival analysis with advanced and user-friendly statistical tools for experimental biologists in the field of aging research.1127Ysciescopu

KIN-4/MAST kinase promotes PTEN-mediated longevity of Caenorhabditis elegans via binding through a PDZ domain

PDZ domain-containing proteins (PDZ proteins) act as scaffolds for protein-protein interactions and are crucial for a variety of signal transduction processes. However, the role of PDZ proteins in organismal lifespan and aging remains poorly understood. Here, we demonstrate that KIN-4, a PDZ domain-containing microtubule-associated serine-threonine (MAST) protein kinase, is a key longevity factor acting through binding PTEN phosphatase in Caenorhabditis elegans. Through a targeted genetic screen for PDZ proteins, we find that kin-4 is required for the long lifespan of daf-2/insulin/IGF-1 receptor mutants. We then show that neurons are crucial tissues for the longevity-promoting role of kin-4. We find that the PDZ domain of KIN-4 binds PTEN, a key factor for the longevity of daf-2 mutants. Moreover, the interaction between KIN-4 and PTEN is essential for the extended lifespan of daf-2 mutants. As many aspects of lifespan regulation in C. elegans are evolutionarily conserved, MAST family kinases may regulate aging and/or age-related diseases in mammals through their interaction with PTEN.11Ysciescopu

A Novel Patent Similarity Measurement Methodology: Semantic Distance and Technological Distance

Measuring similarity between patents is an essential step to ensure novelty of innovation. However, a large number of methods of measuring the similarity between patents still rely on manual classification of patents by experts. Another body of research has proposed automated methods; nevertheless, most of it solely focuses on the semantic similarity of patents. In order to tackle these limitations, we propose a hybrid method for automatically measuring the similarity between patents, considering both semantic and technological similarities. We measure the semantic similarity based on patent texts using BERT, calculate the technological similarity with IPC codes using Jaccard similarity, and perform hybridization by assigning weights to the two similarity methods. Our evaluation result demonstrates that the proposed method outperforms the baseline that considers the semantic similarity only

Source signatures from combined isotopic analyses of PM2.5 carbonaceous and nitrogen aerosols at the peri-urban Taehwa Research Forest, South Korea in summer and fall.

Isotopes are essential tools to apportion major sources of aerosols. We measured the radiocarbon, stable carbon, and stable nitrogen isotopic composition of PM2.5 at Taehwa Research Forest (TRF) near Seoul Metropolitan Area (SMA) during August-October 2014. PM2.5, TC, and TN concentrations were 19.4 ± 10.1 μg m-3, 2.6 ± 0.8 μg C m-3, and 1.4 ± 1.4 μg N m-3, respectively. The δ13C of TC and the δ15N of TN were - 25.4 ± 0.7‰ and 14.6 ± 3.8‰, respectively. EC was dominated by fossil-fuel sources with Fff (EC) of 78 ± 7%. In contrast, contemporary sources were dominant for TC with Fc (TC) of 76 ± 7%, revealing the significant contribution of contemporary sources to OC during the growing season. The isotopic signature carries more detailed information on sources depending on air mass trajectories. The urban influence was dominant under stagnant condition, which was in reasonable agreement with the estimated δ15N of NH4+. The low δ15N (7.0 ± 0.2‰) with high TN concentration was apparent in air masses from Shandong province, indicating fossil fuel combustion as major emission source. In contrast, the high δ15N (16.1 ± 3.2‰) with enhanced TC/TN ratio reveals the impact of biomass burning in the air transported from the far eastern border region of China and Russia. Our findings highlight that the multi-isotopic composition is a useful tool to identify emission sources and to trace regional sources of carbonaceous and nitrogen aerosols