Search Results (16)

To address the challenges of radar multi-target detection in marine environments, this paper proposes an information geometry (IG)-based, two-stage track-before-detect (TBD) framework. Specifically, multi-target measurements are first modeled on the manifold, leveraging its geometric properties for enhanced detection. The designed scoring function incorporates both the feature dissimilarity between targets and clutter, as well as the precise inter-target path associations. Consequently, a novel merit function combining feature dissimilarity and transition cost is derived to mitigate the mutual interference between adjacent targets. Subsequently, to overcome the integrated merit function expansion phenomenon, a two-stage integration strategy combining dynamic programming (DP) and greedy integration (GI) algorithms was adopted. To tackle the challenges of unknown target numbers and computationally infeasible multi-hypothesis testing, a target cancellation detection scheme is proposed. Furthermore, by exploiting the independence of multi-target motions, an efficient implementation method for the detector is developed. Experimental results demonstrate that the proposed algorithm inherits the superior clutter discrimination capability of IG detectors in sea clutter environments while effectively resolving track mismatches between neighboring targets. Finally, the effectiveness of the proposed method was validated using real-recorded sea clutter data, showing significant improvements over conventional approaches, and the signal-to-clutter ratio was improved by at least 2 dB. Full article

In low-carbon transition policy management, rationally determining the energy-related carbon emission responsibilities (ERCERs) across multiple regions is a fundamental issue. Reasonable allocation must take into account regional heterogeneities, such as energy endowments, economic development levels, industrial structures, and complex interconnections within the multi-regional energy supply chain. Previous studies mostly analyzed it via the multi-regional input–output (MRIO) model on the energy-consumption side, often neglecting the regional distribution of energy production and inter-regional energy transport on the energy-production side. This limitation risks a mismatch between energy policies and economic policies in practical policy governance. To address this gap, this study develops an energy allocation-induced MRIO (EA-MRIO) method integrating energy allocation analysis and an MRIO model to trace ERCER transmissions holistically across the entire energy supply chain. The framework covers seven stages including energy supply, inter-regional energy transport, direct energy consumption of end-use sectors, inter-regional intermediate products input and output, final products supply, inter-regional final products transport, and final demand, applied to a case study of China’s 31 provinces in 2017. Results show that ERCERs mainly transfer from western and northern regions to eastern and southern coastal areas: ERCERs embodied by energy production in western and northern provinces first flow to northern coastal provinces (main intermediate products producers), then to eastern and southern coastal provinces (main final products producers), with 23% ultimately attributed to exports. These findings call for allocating ERCERs based on different subregions’ roles within the national energy–economic system to facilitate more equitable and effective carbon reduction policymaking. Full article

This study presents an integrated geospatial framework for assessing the risk to high-speed railway (HSR) infrastructure, combining a persistent scatterer interferometric synthetic aperture radar (PS-InSAR) analysis with multi-criteria decision-making in a geographic information system (GIS) environment. Focusing on the Honam HSR corridor in South Korea, the model incorporates both maximum ground deformation and subsidence velocity to construct a dynamic hazard index. Social vulnerability is quantified using five demographic and infrastructural indicators, and a two-stage analytic hierarchy process (AHP) is applied with dependency correction to mitigate inter-variable redundancy. The resulting high-resolution risk maps highlight spatial mismatches between geotechnical hazards and social exposure, revealing vulnerable segments in Gongju and Iksan that require prioritized maintenance and mitigation. The framework also addresses data limitations by interpolating groundwater levels and estimating train speed using spatial techniques. Designed to be scalable and transferable, this methodology offers a practical decision-support tool for infrastructure managers and policymakers aiming to enhance the resilience of linear transport systems. Full article

The inherent non-ideal characteristics of circuit components and inter-channel mismatch errors induce nonlinear amplitude and phase distortions in time-interleaved pipelined analog-to-digital converters (TI-pipelined ADCs), significantly degrading system performance. Limited by prior modeling, conventional digital calibration methods only correct partial errors, while machine learning (ML) approaches achieve comprehensive calibration at a high computational cost. This work proposes an ensemble calibration framework that combines polynomial modeling and ML techniques. The ensemble calibration framework employs a two-stage correction: a learned Volterra front-end performs forward mapping to compensate static baseline nonlinear distortions, while a lightweight neural network back-end implements inverse mapping to correct dynamic nonlinear distortions and inter-channel mismatch errors adaptively. Experiments conducted on TI-pipelined ADCs show improvements in both the spurious-free dynamic range (SFDR) and signal-to-noise and distortion ratio (SNDR). It is noteworthy that in two ADCs fabricated using 40 nm CMOS technology, the 12-bit, 3000 MS/s silicon-validated four-channel TI-pipelined ADC exhibits SFDR and SNDR improvements from 35.47 dB and 35.35 dB to 79.70 dB and 55.63 dB, respectively, while the 16-bit, 1000 MS/s silicon-validated four-channel TI-pipelined ADC demonstrates an enhancement from 38.62 dB and 40.21 dB to 80.90 dB and 62.43 dB, respectively. Furthermore, a comparison with related studies reveals that our method achieves comprehensive calibration performance for wide-band inputs while substantially reducing computational complexity, requiring only 4.4 K parameters and 8.57 M floating-point operations per second (FLOPs). Full article

This manuscript provides insight into optimally noise-matched three-stage Low-Noise Amplifiers (LNAs) by proposing a novel chart that illustrates the relationship between the gain of a three-stage LNA and inter-stage mismatch levels. Under certain conditions, the chart also indicates the required feedback inductor values for all transistors. It is demonstrated that, under the specific assumption of optimal noise and signal matching, the LNA gain depends on the levels of two inter-stage mismatches. Contrary to common belief, the results show that the LNA gain increases as the inter-stage mismatch levels rise. This finding is supported through the discussion of two LNA designs, one with lower and one with higher inter-stage mismatch levels, achieving gains of 24 dB and 26 dB, respectively, with a Noise Figure of 1.7 dB at the center design frequency of 28 GHz. Subsequently, one LNA topology is validated in a Monolithic Microwave Integrated Circuit (MMIC) implementation using WIN Foundry’s PIH1-10 GaAs E-mode technology. The MMIC characterization aligns with the simulated behavior, accounting for the unavoidable losses in the matching networks. Full article

Northwest China has been facing a contrast between water resource shortage and rapid economic and social development for a long time, and the enhancement of water resource carrying capacity (WRCC) is of strategic significance in solving this contradiction. In this study, a comprehensive evaluation system of water resource carrying capacity is constructed to define the characteristics of Northwest China, which innovatively integrates the four major systems of water resources, economy, society, and the ecological environment. The improved TOPSIS model is applied to systematically evaluate the dynamic evolution of WRCC in the five provinces (autonomous regions) of the Northwest region from 2000 to 2022. The obstacle degree diagnosis model is used to deeply analyze the spatiotemporal evolution of the main constraining factors. The study finds the following: (1) the Northwest WRCC grows slowly amidst fluctuations, with insignificant inter-regional differences, but at a much slower rate than GDP growth in the same period; (2) WRCC in the Northwest region exhibits significant regional differentiation, with Ningxia and Xinjiang maintaining steady upward trends, while Shanxi, Gansu, and Qinghai show a fluctuating upward trend; (3) the constraining factors for WRCC improvement exhibit obvious regional characteristics and time-stage characteristics, with a spatial mismatch of water resource supply and demand, and with low population and economic agglomeration being the core bottlenecks constraining WRCC improvement in the Northwest region. Based on empirical analysis, this study provides customized WRCC improvement strategies for each province (autonomous region), providing scientific decision-making support for the sustainable use of water resources in the Northwest region. Full article

As the preferred architecture for high-speed and high-resolution analog-to-digital converters (ADC), the accuracy of pipelined ADC is limited mainly by various errors arising from multiple digital-to-analog converters (MDAC). This paper presents a multi-dimensional (M-D) MDAC calibration based on a genetic algorithm (GA) in a 12-bit 750 MS/s pipelined ADC. The proposed M-D MDAC compensation model enables capacitor mismatch and static interstage gain error (IGE) compensation on the chip and prepares for subsequent background calibration based on a pseudo-random number (PN) injection to achieve accurate compensation for dynamic IGE. An M-D coefficient extraction scheme based on GA is also proposed to extract the required compensation coefficients of the foreground calibration, which avoids falling into local traps through MATLAB. The above calibration scheme has been verified in a prototype 12-bit 750 MS/s pipelined ADC. The measurement results show that the signal-to-noise and distortion ratio (SNDR) and spurious-free dynamic range (SFDR) are increased from 49.9 dB/66.7 dB to 59.6 dB/77.5 dB with the proposed calibration at 25 °C. With the help of background calibration at 85 °C, the SNDR and SFDR are improved by 3.4 dB and 8.8 dB, respectively. Full article

In wireless applications, such as radars, tens of MHz signals need to be quantized using an analog-to-digital converter (ADC) with a large dynamic range. The detected signal amplitude can be random, with a small or large amplitude. In addition, the dynamic performance is degraded by capacitor mismatches. A 16-bit 120 MS/s pipelined ADC implemented in a 180 nm complementary metal–oxide–semiconductor (CMOS) process is presented in this work. We propose a multi-level dither technique that can significantly enhance the ADC linearity. The injected dither also helps improve the linearity when the ADC handles an input signal with a small amplitude. Traditional dither injection leads to an increase in the amplifier output swing. A counteracting dither injection scheme, both in sub-flash ADC and the multiplying digital-to-analog converter (MDAC), is proposed to remedy this issue. Moreover, capacitor mismatches in the first three pipeline stages are calibrated in a foreground way. The inter-stage residue gain accuracy is guaranteed by a gain-boosting amplifier. To demonstrate the effectiveness of the dither scheme, we obtained the dynamic performance of the ADC with a small input signal (−12 dBFS). The proposed calibration and dither injection technique improved the spurious-free dynamic range (SFDR) from 77 dBc to 85 dBc with −12 dBFS input. With −1 dBFS input, the SFDR remained at over 85 dBc, reaching up to the Nyquist input frequency. Therefore, the dither scheme enhances the dynamic performance when the ADC handles a signal with small amplitude. Full article

Accessibility to transportation is a crucial factor for economic growth. Transportation land, defined as the land used to support transportation infrastructure, such as city and inter-city rail, ports, and air travel, is a critical element for constructing transportation facilities and has attracted increasing attention from researchers and policy makers. Transportation land transfer (TLT) is defined as the act by which the state transfers transportation land-use rights to a land user (collective or individual) within a certain period of time as the land owner (all land in China is owned by the state). The land user pays a land-use right transfer fee to the state. This article first reveals the multidimensional effect between TLT and economic growth based on data from China’s 30 provinces for 2007–2019. The study found the following. (1) A continuous increase in the availability of transportation land is vital to ensure sustainable economic growth, and the construction of transportation land between adjacent areas has positive spatial spillover effects. (2) These positive effects work through three mechanisms, i.e., increased employment, industrial interactions, and improvements in economic operational efficiency, with a time lag. (3) The positive effects of TLT on economic growth have significant heterogeneous moderating effects on the differences in the economic development stage, the level of industrial structure, and urbanization rate. The study expands the front-end to back-end analysis of land use, provides a reference for countries and regions at different stages of development to promote economic growth using transportation land construction, and presents beneficial insights for governments to efficiently avoid the mismatch of transportation land resources. Full article

In this study, a pipelined noise-shaping successive-approximation register analog-to-digital converter (PLNS-SAR ADC) structure was proposed to achieve high resolution and to be free from comparator design requirements. The inter-stage amplifier and integrator of the PLNS-SAR ADC were implemented through a ring amplifier with high gain and speed. The ring amplifier was designed to improve power efficiency and be tolerant to process–voltage–temperature (PVT) variation, and uses a single loop common-mode feedback (CMFB) circuit. By processing residual signals with a single ring amplifier, power efficiency can be maximized, and a low-power system with 30% lower power consumption than that of a conventional PLNS-SAR ADC is implemented. With a high-gain ring amplifier, noise leakage is greatly suppressed, and a structure can be implemented that is tolerant of mismatches between the analog loop and digital correction filters. The measured signal to noise distortion ratio (SNDR) is 70 dB for a 5.15 MHz bandwidth (BW) at a 72 MS/s sampling rate (Fs) with an oversampling ratio (OSR) of 7, and the power consumption is 2.4 mW. The ${\mathrm{FoM}}_{\mathrm{S},\mathrm{SNDR}}$ (= SNDR + ${10\log }_{10}$BW/Power) is 163.5 dB. The proposed structure in this study can achieve high resolution and wide BW with good power efficiency, without a filter calibration process, through the use of a ring amplifier in the PLNS-SAR ADC. Full article

This work presents a 12 bit 200 MS/s dual-residue pipelined successive approximation registers (SAR) analog-to-digital converter (ADC) with a single open-loop residue amplifier (RA). By using the inherent characteristics of the SAR conversion scheme, the proposed ADC sequentially generates two residue levels from the single RA, which eliminates the need for inter-stage gain-matching calibration. To convert the sequentially generated the two residues, a capacitive interpolating SAR ADC (I-SAR ADC) is also proposed. The I-SAR ADC is very compact because it consists of the one comparator, a CDAC, and control logic like a conventional SAR ADC. In addition, the I-SAR ADC needs no static power dissipation for the residue interpolation. A prototype ADC fabricated in a 40 nm CMOS technology occupies an active area of 0.026 mm². At a 200 MS/s sampling-rate with the Nyquist input, the ADC achieves an SNDR (Signal-to-Noise distortion ratio) of 62.1 dB and 67.1 dB SFDR (Spurious-Free Dynamic Range), respectively. The total power consumed is 3.9 mW under a 0.9 V supply. Without any inter-stage mismatch calibration, the ADC achieve Walden Figure-of-Merit (FoM) of 19.0 fJ/conversion-step. Full article

Background and Objectives: Current recommendations and treatment regimens in breast cancer are a reflection of its heterogeneity on multiple levels including histological subtypes, grading, molecular profiling, and numerous prognostic indices. Although based on extensive research, current guidelines are not explicit in the case of surgical specimens showing various degrees of mismatch between different parts of the same tumor and even more so between multicentric lesions. Synchronous breast cancer is the ideal prototype for studying inter- and intra-tumoral heterogeneity, therefore we envisaged that a study on patients with multicentric and multifocal lesions could contribute to the reshaping of the staging, prognosis, and treatment of breast malignancies. Material and Methods: A prospective observational study was conducted between January 2013 and May 2017 on 235 patients diagnosed with breast cancer (BC) and surgically treated at Emergency University Hospital, Bucharest. Thirty-seven patients had multiple breast tumors and were eligible for assessment of the heterogeneity of their lesions. Results: 6 were multicentric and 31 multifocal. The number of foci varied from 2 to 11. We encountered numerous mismatches between the index and the secondary tumors, as follows: 3 cases (8.1%) with histopathological mismatch, 13 (35.1%) with different grades of differentiation, 11 (29.8%) with ER (Estrogen Receptors) status mismatch, 12 (32.4%) with PR (Progesterone Receptors) status mismatch, 8 (21.6%) with molecular phenotype mismatch, and 17 (45.9%) cases with variable Ki-67. After careful analysis of index and secondary tumors, apart from the mismatches reported above, we discovered that the secondary tumors were actually dominant in 5 cases (13.5%), and therefore at least those cases had to be reclassified/restaged, as the supplementary data commanded changes in the therapeutic decision. Conclusions: For synchronous breast tumors, the current Tumor-Node-Metastasis (TNM) staging system ignores not only the histopathological and immunohistochemical characteristics of the secondary foci, but also their size. When secondary lesions are more aggressive or their cumulative mass is significantly bigger than that of the index tumor, the treatment plan should be adapted accordingly. We believe that information obtained from examining secondary foci in synchronous breast cancer and assessment of the cumulative tumoral mass should be reflected in the final staging and definitive treatment. The clinical benefit of staging the patients based on the most aggressive tumor and the cumulative tumoral burden rather than according to the biggest single tumor, will avoid under-treatment in cases with multifocal/multicentric BC displaying intertumoral mismatch. Full article

This paper presents a four-channel time-interleaved 3GSps 12-bit pipelined analog-to-digital converter (ADC). The combination of master clock sampling and delay-adjusting is adopted to remove the time skew due to channel mismatches. An early comparison scheme is used to minimize the non-overlapping time, where a custom-designed latch is developed to replace the typical non-overlapping clock generator. By using the dither capacitor to generate an equivalent direct current input, a zero-input-based calibration is developed to correct the capacitor mismatch and inter-stage gain error. Fabricated in a 40 nm CMOS process, the ADC achieves a signal-to-noise-and-distortion ratio (SNDR) of 57.8 dB and a spurious free dynamic range (SFDR) of 72 dB with a 23 MHz input tone. It can achieve an SNDR above 52.3 dB and an SFDR above 61.5 dB across the entire first Nyquist zone. The differential and integral nonlinearities are −0.93/+0.73 least significant bit (LSB) and −2.8/+4.3 LSB, respectively. The ADC consumes 450 mW powered at 1.8V, occupies an active area of 3 mm × 1.3 mm. The calculated Walden figure of merit reaches 0.44 pJ/step. Full article

Tumor DNA mismatch repair (MMR) deficiency testing is important to the identification of Lynch syndrome and decision making regarding adjuvant chemotherapy in stage II colorectal cancer (CRC) and has become an indispensable test in metastatic tumors due to the high efficacy of immune checkpoint inhibitor (ICI) in deficient MMR (dMMR) tumors. CRCs greatly benefit from this testing as approximately 15% of them are dMMR but only 3% to 5% are at a metastatic stage. MMR status can be determined by two different methods, microsatellite instability (MSI) testing on tumor DNA, and immunohistochemistry of the MMR proteins on tumor tissue. Recent studies have reported a rate of 3% to 10% of discordance between these two tests. Moreover, some reports suggest possible intra- and inter-tumoral heterogeneity of MMR and MSI status. These issues are important to know and to clarify in order to define therapeutic strategy in CRC. This review aims to detail the standard techniques used for the determination of MMR and MSI status, along with their advantages and limits. We review the discordances that may arise between these two tests, tumor heterogeneity of MMR and MSI status, and possible explanations. We also discuss the strategies designed to distinguish sporadic versus germline dMMR/MSI CRC. Finally, we present new and accurate methods aimed at determining MMR/MSI status. Full article

In this article, a highly efficient power module is presented with two class-E power amplifiers and an adaptive power combiner for transmitting output powers >100 W at 6.78 MHz in a wireless power transfer system. The losses caused by the combiners and interstage matching circuits or mismatching between the amplifier, and the combiners can significantly reduce the overall efficiency of the power module. To achieve an efficient combination of the output amplifier signals, the adaptive power combiner is proposed based on the consideration of the optimum load impedance characteristics of the power amplifiers. The input impedance of the combiner is designed using series capacitors and resistors between the two input ports of the combiner and the two output signals of the class-E amplifiers at the optimum load condition. The output performances of the proposed module can decrease based on the component mismatch between the two power amplifiers. The proposed power module was implemented on an FR4 PCB, with a 15 mm metal heat sink, and demonstrated an output power of 123.3 W, a power-added efficiency of 85.7%, and a power gain of 25.6 dB at 6.78 MHz. The second harmonic suppression of the module was 37 dBc. Full article