Final Layout Research Articles

Layout optimization and Performance of Large Array of imaging atmospheric Cherenkov Telescope (LACT)

Abstract Large Array of imaging atmospheric Cherenkov Telescope (LACT) is an array of 32 Cherenkov telescopes with 6-meter diameter mirrors to be constructed at the LHAASO site. In this work, we present a study on the layout optimization and performance analysis of LACT. We investigate two observation modes: large zenith angle observations for ultra-high energy events and small zenith angle observations for lower energy thresholds. For large zenith angles (60°), simulations show that an 8-telescope subarray can achieve an effective area of $3 ~\rm km^2$ and excellent angular resolution. For small zenith angles, we optimize the layout of 4-telescope cells and the full 32-telescope array. The threshold of the full array is about $200~\rm GeV$, which is particularly crucial for studying transient phenomena, including gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). This study provides important guidance for the final LACT layout design and performance estimates under different observational conditions, demonstrating LACT's potential for deep observations of ultra-high energy \gray sources and morphological studies of PeVatrons, as well as time-domain \gray astronomy.

Power-efficient wideband programmable pseudo differential ring oscillator CP-PLL

A power-efficient, wide-band, programmable pseudo-differential ring-oscillator charge-pump phase-locked loop (CP-PLL) is proposed. The ring-VCO, characterized by its low power consumption and broadband, is achieved based on a feedforward pseudo-differential configuration. The linearity of ring-VCO is improved by using the source negative feedback topology. Through the rail-to-rail operatingamplifier clamping current source, the current matching accuracy is improved to realize a high-performance CP circuit. The results show that the output frequency range of the phase-locked loop is 0.6–6 GHz at a 1.2 V supply voltage, and the power consumption is 1.372 mW at 5 GHz with a lock-up time of 1.72 μs and RMS jitter of 9.3 ps. The power consumption is as low as 0.643 mW at 2.5 GHz and 1.067 mW at 4 GHz, and the final layout area is 0.00716 mm2. The implemented CP-PLL can be used effectively in wireless RF communication system of NB-IoT and intelligent edge computing scenario.

Method for Collaborative Layout Optimization of Ship Equipment and Pipe Based on Improved Multi-Agent Reinforcement Learning and Artificial Fish Swarm Algorithm

The engine room is the core area of a ship, critical to its operation, safety, and efficiency. Currently, many researchers merely address the ship engine room layout design (SERLD) problem using optimization algorithms and independent layout strategies. However, the engine room environment is complex, involving two significantly different challenges: equipment layout and pipe layout. Traditional methods fail to achieve optimal collaborative layout objectives. To address this research gap, this paper proposes a collaborative layout method that combines improved reinforcement learning and heuristic algorithms. For equipment layout, the engine room space is first discretized into a grid, and a Markov decision process (MDP) framework suitable for equipment layout is proposed, including state space, action space, and reward mechanisms suitable for equipment layout. An improved adaptive guided multi-agent Q-learning (AGMAQL) algorithm is employed to train the layout model in a centralized manner, with enhancements made to the agent’s exploration state, exploration action, and learning strategy. For pipe layout, this paper proposes an improved adaptive trajectory artificial fish swarm algorithm (ATAFSA). This algorithm incorporates a hybrid encoding method, adaptive strategy, scouting strategy, and parallel optimization strategy, resulting in enhanced stability, accuracy, and problem adaptability. Subsequently, by comprehensively considering layout objectives and engine room attributes, a collaborative layout method incorporating hierarchical and adaptive weight strategies is proposed. This method optimizes in phases according to the layout objectives and priorities of different stages, achieving multi-level optimal layouts and providing designers with various reference schemes with different focuses. Finally, based on a typical real-world engine room engineering case, various leading algorithms and strategies are tested and compared. The results show that the proposed AGMAQL-ATAFSA (AGMAQL-ATA) exhibits robustness, efficiency, and engineering practicality. Compared to previous research methods and algorithms, the final layout quality improved overall: equipment layout effectiveness increased by over 4.0%, pipe optimization efficiency improved by over 40.4%, and collaborative layout effectiveness enhanced by over 2.2%.

Analysis of Parasitic Parameters and Winding Loss Characteristics of High-Frequency Transformer under Different Winding Structures

Abstract With the development of the smart grid and the increasing access of renewable energy to the distribution grid, the traditional AC power grid puts forward an urgent demand for power electronic transformer (PET). The high-frequency transformer (HFT) serves as the core equipment of PET, and its electromagnetic structure and parasitic parameters are the hot spot of study in the field of power electronics. In this paper, the parasitic parameters, winding loss, and leakage magnetic field characteristics of the 20 kHz, 20 kVA HFT are investigated under different winding structures. The results show that the higher the degree of crossover of HFT winding, the lower the leakage magnetic field. The cross winding reduces winding loss and leakage inductance, and also attenuates the impact of frequency variations. The higher the winding height, the lower the leakage inductance. As the insulation thickness increases, the leakage inductance rises. The distribution capacitance varies opposite to the leakage inductance. Based on the analysis of winding loss and parasitic parameters, as well as the consideration of insulation, the final winding layout, the height of winding and the thickness of insulation of the HFT are determined.

Facility layout design of bag and apparel factory with systematic layout planning and computerized relative allocation of facilities technique method

The high market attractiveness index and competitive position made Dewi Media Lestari invest in building a new factory. The factory specifically is used to produce convection products and apparel. Development is carried out using a systematic layout planning and computerized relative allocation of facilities technique. The objective of this research is to obtain an ideal layout that can minimize the distance between departments. As a result, there are nine departments with a total area of 385 m2 consisting of 18 m2loading dock department, 36 m2 raw material department, 86 m2cutting department, 42 m2 branding department, 21 m2 screen printing department, 105 m2 sewing department, 28 m2 finishing department, 28 m2 packing department, and 21 m2 warehouse department. Material handling costs for the initial layout produced using the systematic layout planning method are IDR 29,808.95 per day. After adjusting with Computerized Relative Facility Allocation Technique, the most ideal final layout was produced with minimal material handling costs of IDR 24,411.40 per day.

Design optimization of offshore wind farm layout based on game theory

In offshore wind farm (OWF) planning, traditional methods usually use global optimal strategies. In this paper, game theory is applied to the multi-objective optimization of wind turbine (WT) micro-siting and cabling in an OWF. This method considers the real situation where two different teams may choose the global optimal or the local optimal solution. Firstly, the wind speed deficit in the OWF is estimated using the Gaussian wake model. The objective function and constraints of this optimization problem are formulated. Secondly, the game strategies are exhaustively enumerated. The strategies are allocated to the game space matrix and the payoffs are calculated. The above steps are repeated after redistributing the design permissions. Finally, the Nash front is formed and compared with the Pareto optimum. From simulation results, it can be observed that different Nash solutions can be obtained using different strategy permission allocation methods. So the final layout of the OWF should be determined according to different strategy allocation methods when planning the OWF.

Initiating and integrating user-centred design in upgrading the e-learning layout: a case study on FlexLearn (Brightspace) 2.0 template

PurposeThe purpose of this paper is to articulate how the user experience (UX) approach was initiated and integrated into the centre’s scope of operations with the objective of improving the e-learning layout on the D2L learning management system (LMS). One of the most effective ways to collect user feedback has historically been to evaluate user interfaces using strategies from user testing. The integration of a UX approach by the Centre for ODL Experiences (COLE) at Wawasan Open University has led to a more user-oriented design of FlexLearn by conducting user testing on students as the target users of the platform and gathering course leaders’ (CLs) feedback after the presentation of the new template.Design/methodology/approachSince the process of design and development is a looping process, the first user testing methods employed were observation and interviews, which were conducted over the course of numerous sessions. The data collection used a mixed-methods approach, combining quantitative demographic and background data with qualitative feedback from open-ended questions and real-time interview responses. A standardized questionnaire gathered demographic information, while questions for feedback forms and interviews were adjusted based on specific tasks to explore usability and user interactions comprehensively.FindingsThe findings revealed overall positive feedback, with some concerns highlighted by the students who claimed to have trouble navigating the courses during the initial prototype. In addition to the qualitative data from the user testing session, a quantitative method based on an online questionnaire was also utilised for the CLs after the presentation of the final layout. Positive responses were received from the CLs, and constructive suggestions were considered for FlexLearn 3.0.Research limitations/implicationsThis paper is among the first that articulates the process of initiating and integrating user-centred design in an effort to improve the user experience of online and ODL platforms and LMSs. It will contribute to a dialogue on investigating and prioritising learners’ ODL experiences to ensure education equity across all levels or categories of students, which aligns with the United Nations Sustainable Development Goals.Practical implicationsThe integration of UX and user testing allows us to better identify what users like, their concerns and their needs. We gain important input on how easy or difficult it is to use the system, move around it and how much they enjoy using it. This feedback helps us make changes to the design so that the final product is more in line with what users want. It also allows us to discover problems before they become major, saving time and effort later on. Finally, integrating user input improves the LMS, delivering a more fun and successful learning experience for everyone.Social implicationsUser-friendly systems arise as institutions prioritise user-centred design, breaking down barriers for various learners. This develops an innovative culture, improving present learning experiences and setting a precedent for future generations. The emphasis on user demands helps to create a more accessible, adaptive and egalitarian educational landscape by connecting education with current technological trends. As education becomes more inclusive, the broader community benefits, emphasising the beneficial social impact of LMS user testing.Originality/valueBy articulating the process of integrating user testing on an LMS/e-learning prototype, helps us understand what users like, where they face problems and what needs improvement. By involving users in testing, we get valuable feedback on how easy it is to use the system, navigate around and overall, how much they enjoy using it. Case studies like this also offer universities concrete examples of real-world challenges and successes.

A two-step topology and layout wind farm optimization approach

A novel two-step approach is presented to optimize the placement of wind turbines within a wind farm. The goal is to maximize the annual energy production, while the topology and layout of the wind turbines are optimized in sequence with a two-step procedure using gradient-based algorithms. In particular, in the first step the topology of the wind farm is optimized. A grid of potential wind turbine locations is defined, and continuous density variables ranging from zero to one are assigned to each location. The variables indicate the presence or absence of a wind turbine. Throughout the topology optimization process, we penalize the intermediate values of these variables, implicitly pushing the algorithm towards crisp 0-1 final layouts. Constraints are imposed on the minimum and maximum number of wind turbines and the spacing between them. Subsequently, in the second step, we refine the wind farm layout by optimizing the coordinates (x, y) of the wind turbines, which are initialized based on the optimal topology obtained in the first step. Numerical findings demonstrate the capability of the proposed approach to identify non-intuitive optimized wind farm layouts, with reasonable computational resources and time.

Usulan Perancangan Tata Letak Fasilitas Produksi Dengan Metode BLOCPLAN Untuk Meningkatkan Produktivitas CV. Madu Apiari Mutiara

CV. Madu Apiari Mutiara is a company that operates in the field of derivative honey products such as pure honey, candy, soap, and health products such as propolis and other derivative products which have various shapes and compositions. This condition makes it necessary to have the most efficient spatial layout of work areas and production facilities in order to increase work morale and work productivity in terms of the layout of production facilities. The method used to solve this problem is the BLOCPLAN method. This method can solve facility layout problems in CV Madu Apiari Mutiara production houses with the level of close relationship, area requirements, taking into account the distance of material movement and final layout. The area on CV. Madu Apiari Mutiara is 100 m2, the total area requirement is 70.48 m2. There are 3 alternative layouts in the BLOCPLAN method, the proposed layout chosen is based on the R-Score value which is close to 1, namely the 2nd layout with a material movement distance efficiency of 8.1 meters or 20.9%.

Designing and implementing a new icon-based difficult airway cart: a two-phase prospective qualitative improvement project.

The difficult airway cart is essential for difficult airway management. Recognition of the importance of human factors in critical scenarios promoted the evolution of the difficult airway cart. Limitation to essential equipment, a structured layout, and proper labelling should be observed. We sought to redesign the difficult airway cart accordingly and analyze how perioperative professionals reacted to it. We conducted a two-phase prospective qualitative improvement project involving a multidisciplinary team. In phase 1, we reconfigured our difficult airway cart, including developing icons for labelling the drawers and discussing the equipment content. In phase 2, we delivered a multidisciplinary educational program and pre- and postsession questionnaires were administered to the professionals involved and compared. Phase 1 of the project encompassed 21 participants. We presented the final layout and content of the difficult airway cart. In phase 2, 44 participants responded the presession questionnaires, and 30 participants answered the postsession questionnaires. The results showed that the new design and the implementation program increased the comfort level of professionals involved in a potential airway crisis (presession mean [standard deviation (SD)]: anesthesiologists, 8.0 [1.9]; anesthesia assistants/respiratory therapists [AAs/RTs], 9.3 [0.8]; operating room registered nurses [OR RNs], 6.3 [2.7]; P = 0.001; postsession: anesthesiologists, 8.5 [2.0]; AAs/RTs, 9.6 [0.5]; OR RN, 7.9 [2.0]; P = 0.10). Nevertheless, the improvement was only statistically significant among the OR RNs (presession mean [SD]: 6.3 [2.7]; postsession: 7.9 [2.0]; P = 0.01). Additionally, the program facilitated the recognition of the location of airway equipment in the airway cart (positive responses ranging from 97% to 100%). Our quality improvement project successfully designed and implemented a new visual-based difficult airway cart at our institution. We believe this report enables other institutions to reproduce our project.

Computer-aided hospital layout optimization based on patient flow analysis: A case study from China

Chinese hospitals face challenges with overwhelming patient flow and efficiency. This study focuses on optimizing the outpatient building layout of a general hospital to reduce patients’ travel distances. Electronic medical records (EMRs) (N = 64,315) were analyzed using process mining and systematic layout planning to understand patient flows. Optimal path planning was then used to simulate travel routes and calculate travel distances. The existing layout was optimized using a genetic algorithm to minimize total travel distance for general patients, high-volume department patients, and those with mobility limitations. The final layout was selected manually considering relocation expense, local building codes and regulations, functional continuity, and design flexibility. The layout effectively met the optimization objectives, reducing total travel distance for general outpatients by 5.84%, high-volume department patients by 4.58%, and limited mobility patients by 1.90%. Additionally, the final layout demonstrates outstanding performance in spatial adjacency, site-building relationship, and flow disturbance reduction. This study proposes a computer-aided design framework to improve outpatient building renovations. Utilizing EMR data with a large sample size, it broadens the research scope, refines travel distance calculation methods, and includes practical architectural indicators for a comprehensive analysis. The novelty of the study lies in integrating the optimal path planning method considering travel costs of a multi-story building into the framework of Hospital Layout Problems (HLPs) based on Patient Flow Analysis (PFA), and incorporating the opinions of stakeholders at various stages of computerized design. The method offers the potential to enhance hospital building performance and efficiency with minimal adjustments to existing structures.

Facility layout planning through the ALDEP Method in the wooden cable reels industry

Facility layout planning plays a pivotal role in manufacturing system design, impacting vital metrics such as lead time, handling costs, and space optimization. While a significant portion of research has been invested in refining existing facility layouts, there is a noticeable research gap in devising optimized layouts for new establishments, especially in the value-added wood products domain. Addressing this lacuna, this research focused on designing an efficient department-level layout for a wooden cable drums manufacturing facility in an area of 4150 m2. This facility included both office and production areas. The investigative process was segmented into four distinct phases: Deciding the strategic positioning of the facility on the available plot, defining the functional and spatial requirements for each department, establishing the intricate relationship dynamics between these individual units, and rigorously documenting the most optimal department-level facility layout. For precision in layout creation, the ALDEP algorithm was employed, which was further visualized to offer a comprehensive three-dimensional representation. The final layout seamlessly organized seven departments within the 1st Floor Office Area, eight in the 2nd Floor Office Area, and thirteen within the Production Floor. Efficiency evaluation of these areas yielded scores of -811, 184, and -318, respectively. Conclusively, this research furnished actionable insights for manufacturers within the wood products sector and was expected to be an invaluable reference for academics delving into facility planning and value-added wood products manufacturing.

Multichannel integrated circuit for time-based measurements in 28 nm CMOS

This paper discusses the application-specific integrated circuit prototype dedicated to readout of hybrid pixel X-ray detectors. The circuit is fabricated in 28 nm CMOS technology and occupies 1.1 × 1.1 mm2 of silicon area. Each of 8 × 4 pixels present in the prototype includes an analog front-end and a digital block with two ring oscillators and their supporting circuits. The circuit can operate in single-photon counting mode or time-based measurement mode. The paper discusses in detail the design decisions that influenced the final in-pixel ring oscillator architecture and layout. Measurement results are presented which demonstrate the performance of ring oscillators as well as regular operating modes of the chip: single photon counting and time-over-threshold measurement.

Distribusi Spasial Lamun di Perairan Sekotong Barat-TWP Gita Nada Lombok Barat Menggunakan Citra Landsat 8 OLI

West Sekotong Village is one of the coastal water areas included in the Gita Nada Aquatic Tourism Park (TWP) area which has a seagrass habitat. Seagrass beds in West Sekotong are threatened due to increased tourism and community activities. This research aims to determine the distribution and extent of seagrass beds on the coast of West Sekotong-TWP Gita Nada. This research uses a remote sensing approach through interpretation of Landsat 8 OLI imagery. This research consists of 2 steps, namely image data processing and supporting data. Image data processing includes several stages, namely image data collection, geometric correction, radiometric correction, image cutting, image composite, image data sharpening, image data interpretation, accuracy testing, area measurement, and final layout. Supporting data was obtained by searching related literature, interviews and surveys of activities that have the potential to have an impact on seagrass ecosystems. The research results show that the distribution of seagrass in West Sekotong-TWP Gita Nada covers the coast of the large island (mainland) and the coast of small islands. The distribution of seagrass on the mainland is found on the coasts of Medang, Tanjung Kelor, Batu Kijuk, Tawun, Labu, Kelapa, Pandanan, Gili Genting, Labuan Petung, Temeran, and Gawah Pudak. In the coastal areas of small islands, seagrass is found on Gili Sudak, Gili Tangkong, Gili Nanggu, Gili Poh, and Gili Lontar. The total area of seagrass beds in West Sekotong is around 144.68 ha. On the mainland coast the area is 118.96 ha (82.2%) and on small islands the area is around 25.72 ha (17.8%). The distribution of seagrass in West Sekotong is influenced by many factors, among which those observed in this research are the type of substrate, the presence of river estuaries, and the use of land and coastal waters.

Optimized Development of Hohhot’s New Public Cultural Space Layout Construction Based on Genetic Algorithm under the Perspective of Urban Renewal

Abstract The rational layout and scientific configuration of public cultural space is an important criterion to measure the public service function of a city, whether it is perfect or not. In this paper, Hohhot Downtown is selected as the research object, and the spatial layout structure of the city is explored using the indicators of expansion intensity, compactness and fractal dimension. A layout optimization method based on a genetic algorithm is proposed to build a spatial layout model, set the spatial layout optimization constraints, complete the genetic algorithm optimization through the optimization coding process, and finally solve the Pareto optimization solution set by using the genetic algorithm of Matlab, which results in the optimization scheme of the new public cultural spatial layout of Hohhot City. The results show that six new public cultural space layout schemes of Hohhot are obtained after optimization, and the six layout scores are in the interval of [0.9, 1.0], all of which are excellent. Decision makers can choose the final layout scheme based on their actual situation and decision preferences.

FLAYERS IN THE PLANETS ATMOSPHERE

Planets of the Solar System or exoplanets with atmospheres are complicated to investigate because of the absence of sufficiently intense energy fluxes reflected by their atmospheres. At a sufficiently high brightness of the neighboring star, the atmosphere of the exoplanet gives the absorption spectra of some molecules with a high dissociation potential. If the star's surface temperature is low enough and its activity is low, then the presence of thunderstorm activity in the planet's atmosphere can make it possible to identify it. We show the processes that lead to the formation of flare spectra in the γ- and optical ranges and ways to identify them. It is important to note that current discharges initiate intense nuclear transformations with the formation of proton-rich C11, N13, and O15 nuclei. The spectrum of such a medium is specific and different from the spectra formed by the neighboring star. The statistical irregularity of the frequency of thunderstorms and the variety of conditions in the atmospheres of planets makes it possible to study them due to their illumination in the optical part of the spectrum. It is shown that the integrated optical flow and the detailed γ-spectrum make it possible to trace the time evolution of the lightning head current cord and obtain quantitative values of the current strength. Such fluctuations of the current give changes in the magnetic field of the filament, comparable with the value and even greater than the intrinsic magnetic fields of the planets. To carry out the proposed research, M. Doikov developed a multichannel spectrograph consisting of a γ- and optical spectrometer, a highly sensitive magnetometer, and a radio wave recorder. Its design is discussed in his report. We also note here that the calculations make it possible to determine the statistical parameter of time signals, the operating modes of the equipment, and the selection of the necessary nodes for designing the final working layout of the multichannel spectrometer. The value of the choice of observation site is indicated. In mountainous areas, these are heights of the order of a kilometer. In this case, the devices are near lightning.

Undirected graph representing strategy for general room layout estimation

Room layout estimation aims to predict the spatial structure of a room from a single image. Most existing methods relying on 2D cues are suitable for cuboid rooms, but non-cuboid rooms. 3D layout estimation methods can reconstruct 3D models of general rooms, but they are trained with depth information on high collection costs, consume large computation resources, and run slowly. This paper considers an undirected graph representation method of the general room layouts, which includes cuboid and non-cuboid rooms consisting of a single ceiling, a single floor, and multiple walls. To this end, we first predict the positions of the layout vertices and then use the network automatically learn the connection relationship between the vertices. The final layout is obtained through a simple layout inference post-processing algorithm. The experimental results both on cuboid and non-cuboid datasets validate the effectiveness and efficiency of our method. The code is available at https://github.com/Hui-Yao/2D-graph-layout-estimation.

Diagnosis of Environmental Degradation in the Controlled Landfill Area of New Venetia – ES

Objective: One of the main environmental problems of today's society concerns the final disposal of urban solid waste (MSW), and increasing the generation rates of this waste has become a high priority concern for both environmental preservation and human health. Inadequate final disposal leads to serious environmental impacts, including the risks of contamination of soil, subsoil, surface water and groundwater, even after decommissioning of inappropriate sites. The purpose of this research was to assess the level of degradation in the area around the Controlled Landfill of New Venetia. To do so, documentary, oral and bibliographical research was carried out on the area, technical visits, drawing up maps, applying the Quality Index of Waste Landfills (IQR) with adaptations directed to the reality of the landfill and finally, bacteriological analyzes of surface and underground water were carried out in the surroundings of the area. The application of the IQR resulted in a score of 5.15 and the non-existent or deficient aspects that caused this score were: soil waterproofing, plant protection, drainage and treatment of slurry, drainage of rainwater and gases, geotechnical and groundwater monitoring, presence of flies, birds and animals, occurrence of odors and proximity of bodies of water. The results of the bacteriological analyzes indicated a potential for microbiological contamination in the surface water resource downstream of the landfill, which may be linked to extensive livestock rearing, but may also indicate that the slurry contamination plume is influencing the water quality of the analyzed stream. Evaluate the level of degradation in the area around the Controlled New Veneto Landfill. Theoretical benchmark: The inadequate final layout of MSW results in severe environmental impacts, including the risks of contamination of soil, subsoil, surface water and groundwater, even after decommissioning of inappropriate sites. Furthermore, this inadequate destination generates visual pollution, property devaluation in the environs, the presence of precariously organized waste pickers, and promotes the favoring of disease vectors. Method: The methodology encompassed bibliographical review of the area in question, as well as of the concepts associated with the themes necessary for the research; obtaining data and making maps; characterization of the area; determination of the Quality Index of Waste Landfills (IQR) and bacteriological analysis of ground and surface water. Results and conclusion: The application of the IQR, by means of historical and current characterization and evaluation of the controlled landfill of New Venetia, resulted in a score of 5.15 classifying this in inappropriate conditions. The results of the bacteriological analyzes indicated a potential for microbiological contamination in the surface water resource downstream of the landfill, which may be linked to extensive livestock rearing, but may also indicate that the slurry contamination plume is influencing the water quality of the analyzed stream. Research implications: The results of this research should serve as a basis for reflections and analysis on aspects necessary for the correct implementation of final destination systems of MSW, as well as for the deactivation and recovery of them. In addition, it also supports the study of improvements that can be made in the area of the controlled landfill of New Venetia, to adapt and reduce the impacts and environmental risks of the area. Besides collaborating for the education and environmental awareness of the inhabitants of the municipality. Originality/value: To bring reflections from an analysis of multiple factors and consequences arising from the inadequate final destination of the MSW, emphasizing the importance and necessity of the study and characterization of these sites, administrative political actions and awareness of the population.

Layout Quality Criteria for CMOS Standard Cells of Digital IC

The article is devoted to review and systematization of layout quality criteria for CMOS standard cells used as base core elements in EDA based digital IC design flows. Review of such criteria grouped by various quality aspects is given. It is shown with specific examples, that quality criteria of completed standard cell layouts can be used for a variety of purposes, including: analysis and quality control/assessment of standard cell libraries, identifying possibilities for layout improvements, and selecting the best variant of the layout among alternatives from different vendors (if available). Integral layout quality criterion, which enables flexible prioritization of different layout quality characteristics, is introduced. It is also proposed to use integral criterion for selecting between different layout versions of the same cell, obtained with different layout creation approaches. It is proposed to use branch-and-bound methodology based on quality criteria of partially completed (symbolic) layouts for selection from folded/placed/routed layout versions during the process of automated layout creation. Review of the criteria used for evaluating quality of the intermediate symbolic layouts during different stages of standard cell layout creation flow is also given in the article. Thus, with the thorough selection of intermediate layout versions the effectiveness of final layout is achieved. The results might be applied by standard cell libraries developers, but also by design engineers who should take a decision about different libraries usage based on comparative analysis.

Back Gate Bias Influence on BESOI ISFET Sensitivity

The application of Field Effect Transistors (FETs) to sensors and biosensors allows a mass production, low cost, small size, fast response and, also, the possibility of integrating the device and conditioning signal circuit in the same integrated circuit (IC). The Ion Sensitive Field Effect Transistor (ISFET), invented in 1970 by Piet Bergveld (1), is a device similar to the conventional Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), except that the metal gate is replaced by an inert electrode/pseudo electrode and a sample solution, in order to expose the gate oxide layer to ions present in the solution. The solution charges change the electrical potential in the gate oxide surface and, consequently, the device threshold voltage changes as a function of the ion concentration in the sample solution, being used as a pH sensor. Thus, the ISFET is a very promising device to Point-of-Care (POC) monitoring, such as COVID-19 control (2) and for continuous in vivo monitoring ion activity in biological processes (3)-(6).The BESOI (Back Enhanced Silicon-On-Insulator) MOSFET is a device patented in 2015 by João Antonio Martino and Ricardo Cardoso Rangel (7). This device is easy to fabricate and low cost. In the last years, the research using this device as a sensor/biosensor has been done (8)-(14). This paper presents, for the first time, the BESOI MOSFET working as an Ion Sensitive Field Effect Transistor (ISFET): the BESOI ISFET. Therefore, the focus of this work is to study the device electrical behavior influenced for pH standard solutions.The BESOI ISFET was fabricated at Integrated System Laboratory (LSI) from University of Sao Paulo (USP), Brazil. It is a planar device made on a SOI (Silicon-On-Insulator) wafer with three conventional photolithography steps, in an analogous way to previous work (15) and one more photolithography step to create microchannel and microreservoirs with SU-8 (16) layer to contain the sample solution. The wafer has no doping process (there is only the natural wafer doping of 1015 cm-3). The silicon channel layer and the gate oxide (SiO2) thicknesses are 10 nm and 25 nm, respectively. The buried oxide layer thickness is 200 nm. The drain and source contacts are fabricated with nickel and the contact pads using aluminum. The Figure 1 presents the final device layout and the Figure 2 shows the device schematic drawn.Differently from a conventional ISFET, where the drain current flows at the front interface, in the BESOI ISFET the drain current flows at the back interface. As the BESOI ISFET is a non-intentionally doped device, the free conduction charge layer is formed by biasing the Back Gate electrode (VGB). When a positive enough VGB is applied, electrons are attracted and accumulated at the back interface, and therefore, current flows from source to drain when VDS (Drain bias) is applied. A Platinum (Pt) pseudo-electrode is used to apply front-gate voltage (VGF) to the sample solution.The experimental drain current (IDS) as a function of the front-gate voltage (VGF), for 25 V applied at the back-gate (VGB), is presented in Figure 3.A, which is possible to observe that the neutral pH (pH7) curve stayed between the acid pH (pH4) curve, in the left, and alkaline pH (pH10) curve, in the right. This result shows that the threshold voltage (VTH) is lower for acid pH and higher for alkaline pH, what is compatible with the conventional ISFET results present in the literature (17). To corroborate the experimental measurement result, the device simulation was made with TCAD-Sentaurus (18), based in the paper (19). Figure 3.B shows the same trend for the simulated device with pH solution for any VGB value.In Figure 4, the threshold voltage was analyzed as a function of the pH for different VGB values. The VTH increases (becomes more positive) for alkaline pH values, regardless of the VGB applied. However, the VTH variation in the pH range, between pH4 and pH10, is different for different VGB values. With higher VGB applied, higher is the VTH variation. In Figure 5 Is possible to see clearly that the sensitivity (ΔVTH /ΔpH) increases with the VGB increase probably due to the small influence of the series resistance. In another hand, the acquired sensitivity values for VGB higher than 15 V in this work (about 25-33 mV/pH, approximately), is compatible with results present in the literature for conventional ISFETs with silicon dioxide (SiO2) for gate insulator (20). Figure 1