Low Floor Research Articles

Выставки петровского времени в Русском музее. 1972–2022 гг.

The legacy of Peter the Great’s time in the Russian Museum is quite large. Researchers continue to study the collection of works of the beginning of the XVIII century. Since 1946, an exposition called «Peter’s time» has been equipped in one of the halls of the museum. There are portraits of Peter I painted by foreign artists, parsuns, a plaster mask and a bronze bust of the emperor, desudeports. The works of pensioners Peter – I. Nikitin and A. Matveev are also presented. Many paintings, sculptures and graphics of the beginning of the XVIII century are not included in the exhibition, they are revealed to the viewer only at temporary screenings. Landmark exhibitions were held by the Russian Museum on the 300th anniversary of the birth of Peter the Great in the early 1970s. These are: «Engraving of Peter’s Time» (1971–1972), «Portrait of Peter’s Time» and «Iconography of Peter’s Time» (1973). They were in the halls of the lower floor of the left wing of the Mikhailovsky Palace and in the wing of the Rossi. The advantage of these expositions was the demonstration of rare examples of engraving, painting, parsuna and icon painting of the late XVII – early XVIII centuries. The exhibition «Both the navigator and the carpenter. Peter the Great in Russian Art Culture» (2022) was opened in the halls of temporary exhibitions of the dress circle of the Mikhailovsky Castle. The purpose of the exhibition is to continue the visual practice of the mid to present a trellis hanging of paintings. At the same time, a multimedia visual series, detailed annotated accompaniment, lecture podcasts were introduced. The commemorative practices in the existing exhibition are expressed in the invariant treatment of historical heritage in dialogue with the viewer.

Computerized-adaptive testing versus short forms for pediatric inflammatory bowel disease patient-reported outcome assessment.

Computerized-adaptive testing (CAT) may increase reliability or reduce respondent burden for assessing patient-reported outcomes compared with static short forms (SFs). We compared CAT versus SF administration of the Patient-Reported Outcomes Measurement Information System® (PROMIS®) Pediatric measures in pediatric inflammatory bowel disease (IBD). Participants completed 4-item CAT, 5- or 6-item CAT, and 4-item SF versions of the PROMIS Pediatric measures. We compared average T-scores, intra-class correlations (ICCs), floor and ceiling effects, and standard error of measurement (SEM) across forms, along with mean effect sizes between active versus quiescent IBD disease activity groups. Average PROMIS T-scores across forms were <3 points (minimally important difference) of each other. All forms correlated highly with each other (ICCs ≥0.90) and had similar ceiling effects, but the CAT-5/6 had lower floor effects. The CAT-5/6 had lower SEM than the CAT-4 and SF-4, and the CAT-4 had a lower SEM than the SF-4. Mean effect sizes were similar across forms when contrasting disease activity groups. The CAT and SF forms produced similar score results, but the CAT had better precision and lower floor effects. Researchers should consider PROMIS pediatric CAT if they anticipate that their sample will skew toward symptom extremes.

Will Capacity Mechanisms Conflict with Carbon Pricing?

Climate change and related national mitigation targets make the decarbonization of the power sector an urgent need. The power sector faces the challenge of considering the design and interaction between emission reduction policies, which can sometimes counteract each other. This study proposes a framework that can be used to quantitatively study the qualitative link between carbon pricing and capacity pricing. The framework is validated through a case study in Hokkaido, Japan, and used to further investigate the interaction between the two policies through a System Dynamics simulation model and scenario design. The results indicate that a carbon price would promote the introduction of wind power, as well as the reduction in fossil fuels, while the capacity price will mitigate the boom-and-bust investment cycle and stabilize electricity prices. However, when the two policy-based prices act on the power system simultaneously, the advantages will be offset by each other. The existence of the capacity price partially offsets the emission reduction effect of the carbon price, and the carbon price with a lower floor will also indirectly squeeze the generation space of flexible power plants. In order to address these inefficiencies, this study proposed a capacity price focused on subsidizing flexible power plants and also coupled with a higher floor carbon price, which results in a consistent incentive. It also promotes the decommissioning of carbon-intensive base-load power plants and reduces CO2 emissions significantly.

Psychometric Evaluation of the 'German Neurological Fatigue Index for Multiple Sclerosis (NFI-MS-G)' in a Sample of Rehabilitation Patients with Multiple Sclerosis

The purpose of this study was to provide a patient-reported outcome measure for people with multiple sclerosis (MS) comprehensively reflecting the construct of fatigue and developed upon the assumptions of the Rasch model. The Neurological Fatigue Index - Multiple Sclerosis (NFI-MS) is based on both a medical and patient-described symptom framework of fatigue and has been validated. Therefore, in this study the German version of the NFI-MS (NFI-MS-G) consisting of a physical and cognitive subscale and a summary scale was validated. In this bi-centre-study, 309 people with MS undergoing outpatient rehabilitation or being≥2 months before or after their inpatient rehabilitation completed the German NFI-MS-G twice within 14-21 days together with other questionnaires. Correlation with established questionnaires and Rasch analysis were used for its validation. Additionally, psychometric properties of known-groups validity, internal consistency, test-retest reliability, measurement precision and readability were tested. Finally, the English NFI-MS and German NFI-MS-G were compared with each other to equate the language versions. The NFI-MS-G showed good internal construct validity, convergent and known-groups validity and internal consistency (Cronbach's alpha 0.84-0.93). The physical subscale showed minor local dependencies between items 1 and 7, 2 and 3 and 4 to 6, that could be treated by combining the respective items to testlets. Unidimensionality was found for the physical and cognitive subscales but not for the summary scale. Replacing the summary scale, a 2-domains subtest measuring the higher-order construct of fatigue was created. Good test-retest reliability (Lin's concordance correlation coefficient of 0.86-0.90) and low floor and ceiling effects were demonstrated. The NFI-MS-G was found easily readable and invariant across groups of gender, age, disease duration, timepoint and centre. The German version of the NFI-MS comprehensively represents the construct of fatigue and has adequate psychometric properties. The German version differs from the English original version with respect to a lack of unidimensionality of the summary scale and minor local dependencies of the physical subscale that could be canceled out using a testlet analysis.

Seismic performance of steel braced frames with innovative assembled self-centering buckling restrained braces with variable post-yield stiffness

An innovative assembled self-centering buckling restrained brace (ASC-BRB) with variable post-yield stiffness is proposed in this study, aiming to better control structural responses under earthquakes of different intensity levels. The proposed ASC-BRB consists of the buckling restrained brace (BRB) system and self-centering (SC) system, where the SC system provides the variable post-yield stiffness with trilinear elastic behavior. The overall configuration and restoring force model of the brace are first described, and six independent hysteretic parameters are determined to comprehensively describe its hysteretic behavior. A simplified truss model of the ASC-BRB is established using OpenSees, and the experimental and numerical hysteretic curves coincide well with each other, indicating that the simplified model has satisfactory accuracy. The simplified model is then utilized to investigate the effect of the design parameters on the hysteretic behavior of the ASC-BRB. Nonlinear dynamic analyses are also conducted for three 6-story steel frames with different types of braces. The comparison results indicate that the proposed ASC-BRB with high post-yield stiffness can effectively limit the displacement development at the lower floors, but the structural high-mode effect will be further amplified. Finally, system level parametric analyses are performed to study the influence of brace design parameters on the structural responses, and reasonable values for these design parameters are recommended according to the parametric analysis results.

A review of high-performance MEMS sensors for resource exploration and geophysical applications

MEMS sensors have the advantages of small volume, lightweight, and low cost, therefore, have been widely used in the fields of consumer electronics, industry, health, defence, and aerospace. With their ever-improving performance, MEMS sensors have also started to be used in resource exploration and geophysical applications. However, the requirements of high-precision MEMS sensors for geophysical applications have not been specified in detail. Therefore, this paper systematically analyzes the requirements of high-performance MEMS sensors for prospecting and geophysical applications, including seismic surveillance, Earth tide, volcanic activity monitoring for natural disasters; seismic, gravity, and magnetic resource prospecting; drilling process monitoring and local gravity measurement for gravity aided navigation. Focusing on the above applications, this paper summarizes the state-of-the-art of research on high-performance MEMS sensors for resource exploration and geophysical applications. Several off-the-shelf MEMS sensors have been used for earthquake monitoring, seismic exploration and drilling process monitoring, and a range of MEMS research prototype sensors have successfully been employed for Earth tides measurement and are promising to be used for gravity exploration. MEMS magnetometers should have a lower noise floor to meet the demand for magnetic exploration. MEMS gravity gradiometers are still under early development and will not be deployable in short-term. High-performance MEMS sensors hold the advantages of low-cost, high integration, and capability of working in extreme environments; therefore, they are likely to gradually replace some conventional geophysical instruments in some application areas.

Feasibility study of a practical causal rate-independent damping device for the improved performance of seismic isolated structures

When rate-independent linear damping (RILD) is incorporated into a base-isolated structure, it achieves a similar response displacement reduction effect with significantly lower floor response acceleration compared with linear viscous damping (LVD) with the same loss factor. To address the undesirable stiffness added to an isolation layer when we adopt a mechanical device comprising a few branches of a spring–dashpot link to realize RILD, this study proposes canceling the undesirable isolator stiffness by adding an inerter element and reducing the isolator stiffness. A heuristic optimization method was developed to design the proposed mechanical device to mimic the behavior of RILD. A parametric survey on the optimal designs of the device suggests that the three branches of the spring–dashpot link work best in terms of practicality and feasibility. Seismic control performance was assessed using a 10-story base-isolated building mounted on linear and nonlinear isolation systems. Analyses of linear systems revealed that the proposed device achieved lower inter-story drifts and approximately 40% reduction in floor response acceleration with a 4% increase in isolator displacement compared with the LVD when subjected to high-frequency ground motions. Analyses of the nonlinear systems showed that the displacement control performance of the proposed model was slightly compromised when subjected to ground motions dominated by low-frequency components, thereby identifying a further challenge in developing a causal RILD device for nonlinear structures.

Modeling of Daytime and Nighttime Surface Urban Heat Island Distribution Combined with LCZ in Beijing, China

Along with urbanization, surface urban heat island (SUHI) has attracted more attention. Due to the lack of perspective of spatial heterogeneity in relevant studies, it is difficult to propose specific strategies to alleviate the SUHI. This study discusses the impact of spatial heterogeneity on the day and night SUHI by taking one day and night in Beijing as an example, and uses it to improve the efficiency of SUHI simulation for related planning. This study, based on the local climate zone (LCZ), deeply discusses the relationship between urban morphology and the SUHI. Then, an artificial neural network (ANN) model with the LCZ is developed to predict the distribution of the SUHI. The results show that: (1) In summer, the general SUHI intensity distribution patterns are compact zone &gt; large low-rise zone &gt; open zone and medium floor zone &gt; low floor zone &gt; high floor zone. (2) Building density and albedo in dense areas are higher correlated with the SUHI than open areas. The building height has a significant negative correlation with the SUHI in high-rise zone, but has a positive correlation in middle and low floors. (3) The LCZ improves the overall accuracy of the ANN model, especially the simulation accuracy in the daytime. In terms of regions, LCZ2, LCZ8, and LCZ10 are improved to a higher degree. This study is helpful to formulate the SUHI mitigation strategies of “adapting to the conditions of the LCZ” and provide reference for improving the sustainable development of the urban thermal environment.

Sensitization to Furry Animals in Patients with Suspected Allergic Disease in China: A Multicenter Study.

An objective of this study was to investigate the allergen sensitization characteristics of cat, dog and horse dander in patients with suspected allergic diseases in different geographical regions of Chinese mainland. We invited 2377 patients aged 0-86 years with suspected allergic diseases to participate in a cross-sectional survey in 11 provinces in China. Combined with the questionnaires and animal-specific IgE levels, we analyzed the epidemiological characteristics and risk factors of furry animal sensitization in different regions and populations of Chinese Mainland. Among the 2377 patients with suspected allergic diseases, 14.9% were sensitized to cat dander, 9.3% to dog dander and 5.5% to horse dander. Animal allergens mainly cause low-level sensitization (class 1-3). There was a significant correlation between cat, dog and horse dander allergen sIgE, with correlation coefficients (rs) all greater than 0.750. The majority (46.5%) of sIgE-positive patients were sensitized to at least two animal allergens simultaneously. The prevalence of these animals all showed a trend of increasing first and then decreasing with age, and all reached the peak in young adolescence. As for the geographical factors, the sensitization rate of cats and dogs in Western was significantly higher than that in Eastern (cat: 18.4% vs 9.2%, dog: 11.6% vs 5.5%, all P < 0.001), however, no significant differences were found in horses. Aged ≤6 years, living in Western, and high animal allergen exposure elevated the risk of cat or dog sensitization. Living on a lower floor (aOR: 0.56) was a protective factor for horse sensitization. In this representative sample of Chinese patients with suspected allergic diseases, there was an apparent geographic variation in sensitization to cats and dogs. Age factor and living in Western also had a significant impact on animal allergen sensitization rate.

Fast time-domain current measurement for quantum dot charge sensing using a homemade cryogenic transimpedance amplifier

We developed a high-speed and low-noise time-domain current measurement scheme using a homemade GaAs high-electron-mobility-transistor-based cryogenic transimpedance amplifier (TIA). The scheme is versatile for broad cryogenic current measurements, including semiconductor spin-qubit readout, owing to the TIA's having low input impedance comparable to that of commercial room-temperature TIAs. The TIA has a broad frequency bandwidth and a low noise floor, with a trade-off between them governed by the feedback resistance RFB. A lower RFB of 50 kΩ enables high-speed current measurement with a −3 dB cutoff frequency f−3dB = 28 MHz and noise-floor NF = 8.5 × 10−27 A2/Hz, while a larger RFB of 400 kΩ provides low-noise measurement with NF = 1.0 × 10−27 A2/Hz and f−3dB = 4.5 MHz. Time-domain measurement of a 2-nA peak-to-peak square wave, which mimics the output of the standard spin-qubit readout technique via charge sensing, demonstrates a signal-to-noise ratio (SNR) of 12.7, with the time resolution of 48 ns, for RFB = 200 kΩ, which compares favorably with the best-reported values for the radio frequency reflectometry technique. The time resolution can be further improved at the cost of the SNR (or vice versa) by using an even smaller (larger) RFB, with a further reduction in the noise figure possible by limiting the frequency band with a low-pass filter. Our scheme is best suited for readout electronics for cryogenic sensors that require a high time resolution and current sensitivity and, thus, provides a solution for various fundamental research and industrial applications.

Characteristics of Light Rail Travel Time: Examples from France

The total journey time of Light Rail Vehicles (LRVs) is made up of running time, dwell time (station stops for passenger boarding and alighting), and signal delay (delay of LRVs being stopped by the regular traffic signals). Data from operational surveys of six modern light rail systems in France has shown that LRV running time was 65-71 percent of the total journey time and dwell time was 22-27 percent, while signal delay was 7 to 8 percent of the total journey time. The average operating speed of the Light Rail Transit (LRT) ranged from 17.7 to 22.8 km/h and has an approximate linear relationship to passenger stop frequency (stops/km).Light rail dwell time has been found to follow a log-normal distribution, although the values differed significantly between different LRT systems. The means of the dwell time distribution have the range of 16 to 31 seconds in off-peak periods and 21 to 37 seconds in peak periods. Factors that influence light rail dwell time include the number of passengers at the stops, the number of standees in the vehicles, vehicle design (number of doors, door size, low floor or high floor vehicle, etc.), fare collection system, and the location of LRT stops.The findings in this paper could be used by LRT planners and operators directly in developing and assessing operating and service changes and in providing input to long-range planning procedures. The results can also be used in microscopic simulation modeling studies of LRT in an urban network, such as the TRGMSM model.

Nonlinear Modeling of RC Substandard Beam–Column Joints for Building Response Analysis in Support of Seismic Risk Assessment and Loss Estimation

The paper discusses how joint damage and deterioration affect the seismic response of existing reinforced concrete frames with sub-standard beam–column joints. The available simplified modeling techniques are critically reviewed to propose a robust, yet computationally efficient, technique for simulating the nonlinear behavior of substandard beam–column joints. Improvements over the existing models include the simulation of the cyclic deterioration of joint stiffness and strength, as well as pinching in the hysteretic response, implemented considering a deteriorating hysteretic rule. A fiber-section forced-based inelastic beam–column element is developed, considering improved material models and fixed-end rotation due to bond failure, rebars-slip, and inelastic extension, to simulate the deteriorating cyclic behavior of existing pre-cracked beam–column members. For the assessment of frames with substandard exterior beam–column joints, a nonlinear model for the exterior joint is developed and validated through a full-scale quasi-static cyclic test performed on a substandard T-joint connection. The proposed model allows considering structural performance in risk assessment while accounting for true inelastic mechanisms at the joints. An assessment of a five-story RC frame revealed that the activation of the joint shear mechanism increases the chord rotation demand on the connecting beam members by up to 85%, with increases of up to 62% (mean drift) and 89% (mean + 1.std.) on the lower floors when determining the inter-story drift demand, and the collapse probability of structures subjected to design base ground motions increased from 4.20% to 29.20%.

Trade and the Mosque: An Investigation of Commercial Activities and Mosques in Antalya with Spatial, Legal and Functional Recommendations

Expenditures, such as repair, heating and lighting costs, and payment of mosque staff’s salaries, are the main cost items that need to be satisfied for mosques to continue their services. Throughout history, these expenses have been met sometimes with the state budget, sometimes through waqfs and associations, and sometimes with the cash aid provided by the people directly in Turkey. Adding a commercial function to the mosque, which was built for the sake of continuous income, has been seen in the history of Turkey since the Ottoman period. However, the commercial units dedicated to the mosque during this period were not always close to the mosque; sometimes they could also be located in very remote location. Today, a type of structure is built which can be called a trade and religious building in the lower floor of the mosque, or as a part of the same floor due to space shortage, cost reduction etc. This type of building, which was interpreted with different perspectives, caused problems in terms of perceptibility, ratio and proportion, visuality, accessibility, noise pollution, and the moral values of the mosque, and even became the subject of lawsuits for the closure of commercial functions. In this context, the commercial functions that the mosques added to the structure in order to find financial resources were examined throughout the city center of Antalya. Accordingly, the architectural projects and zoning status of the 15 identified mosques were examined, and a spatial and configuration analysis was made. The functionality of the mosques was discussed with the mosque community, its officials, and the people in the area close to the mosque via focus group discussions, and examples of the issue brought to the judiciary were examined.

Traffic Safety and City Public Transport System: Case Study of Bengaluru, India

Vehicle crashes are a major concern in rapidly growing urban agglomerations. They also have attracted the attention of researchers, academicians, and policy makers. A large body of research literature exists that throws light on the magnitude of this problem and also indicates the interventions required. In a vast majority of Indian cities, buses are the main mode of public transport. An externality of the bus-based public transport system, like any other mode of transport, is the injuries and fatalities arising out of the crashes involving them. Buses are involved in 12-20 percent of fatal crashes in Indian cities. This paper presents an analysis of the fatal crashes that involved public transport buses in Bengaluru, India. The study suggests that low floor buses with mechanical doors and segregated pedestrian and bicycle lanes can have a major impact on reducing fatal crashes of bicycles and pedestrians involving buses.

Determinants of Bus Dwell Time

Bus dwell time data collection typically involves labor-intensive ride checks. This paper reports an analysis of bus dwell times that use archived automatic vehicle location (AVL)/automatic passenger counter (APC) data reported at the level of individual bus stops. The archived data provide a large number of observations that serve to better understand the determinants of dwells, including analysis of rare events, such as lift operations. The analysis of bus dwell times at bus stops is applicable to TriMet, the transit provider for the Portland metropolitan area, and transit agencies in general. The determinants of dwell time include passenger activity, lift operations, and other effects, such as low floor bus, time of day, and route type.

On the Construction of QC-LDPC Codes Based on Integer Sequence With Low Error Floor

Quasi-cyclic low-density parity-check (QC-LDPC) codes have efficient hardware implementation and excellent correcting performance. However, the existence of trapping sets can affect the decoding performance. In this letter, a novel class of QC-LDPC codes based on integer sequence with column weight 3 and girth at least 8 is proposed. If the numbers in the sequence are different, the QC-LDPC codes free of elementary trapping sets ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${b}$ </tex-math></inline-formula> ) with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${a} \leq10$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${b} \leq $ </tex-math></inline-formula> 3 can be constructed. The row weight of the parity check matrix can be arbitrary and we give a lower bound of the circulant permutation matrix (CPM) size. Simulation results show that the generated codes have good performance with low error floor over AWGN channels.

Low-cost measurement-grade microphone powered by MEMS elements and preamplifier housed in 3D printed enclosure

Acoustic measurement-grade microphones with flat frequency responses and adequate sensitivities are a necessary tool for many acousticians and vibroacoustic engineers. These microphones can often cost hundreds, if not thousands, of dollars. With the availability of microelectromechanical systems (MEMs) microphone elements and 3D printers, it is possible to construct drop-in replacements of these measurement grade microphones at the fraction of the cost. A MEMs system was designed with four elements in parallel to reduce uncorrelated noise. The system runs rail-to-rail on a 3.3VDC, Integrated Electronics Piezo-Electric (IEPE) powered preamplifier, producing a nominal sensitivity of 13 mV/Pa. The microphone body is 3D printed, and the final bill of material cost is less than 30 USD. The performance of the microphone was measured experimentally in a semi-anechoic chamber and verified by comparing the data to measurements of a commercial microphone: the PCB Piezotronics 378B02 ½” free-field microphone with a nominal sensitivity of 50 mV/Pa. This presentation will show that the MEMs microphone has a similar electrical noise floor, and lower acoustical noise floor below 1 kHz. The frequency response of the MEMs microphone is flat in the audio band through 10 kHz, making it a suitable replacement for acoustical measurements where its lower sensitivity can be tolerated.

Preventing, predicting, and simulating the noise impact of one indoor music venue on another through a large glass wall

Jaffe Holden has worked on a confidential new project in Cambridge, MA in a proposed new building which will feature a 2-venue performing arts center in the lower floors of the building. The PAC includes a multi-use theater for music, speech, and dance with a large upstage wall made predominantly of a glass curtain-wall system. On the opposite side of the glass is an atrium with a second smaller venue that will also feature loud music programming. The client would like to allow as much flexibility in programming for both spaces as possible, while avoiding acoustic impact between the two spaces. As acoustical consultants on the project, Jaffe Holden modeled different glazing systems and provided recommendations to achieve the project goals. We used our acoustic lab to simulate the effect of different curtain-wall designs and played back the demo to the client to provide a subjective listening evaluation in addition to computational decibel predictions. This paper will study the acoustical challenges with this pairing, the challenges in acoustically modeling the performance of the curtain-wall, the architectural/constructability/budget challenges associated with the curtain-wall, and the lab demo simulation that was used to help the client make design decisions.

Experimental Study on Composite Beam with Various Connections under Midspan Impact Scenarios

The performance of an immediate frame span subjected to a falling-debris-impact scenario is of great importance to investigate the spread of initial damage during a progressive collapse event. If the frame span was not able to resist the impact load from possible falling debris, it would become new debris and impact the lower floor with previous debris. After that, progressive collapse might probably happen. However, the impact mechanism considering the contribution of composite slabs of an immediate span remained unclear currently. Therefore, experimental studies on a series of three half-scale composite beam subassemblies were conducted under impact scenarios. The impact loads were applied via a high-performance drop-weight test machine. Various beam–column connections, including welded unreinforced flange-bolted web, fin plate, and reverse channel connections, which represented rigid connection, hinge connection, and semirigid connection, respectively, were investigated. The structural resistances of the specimens were provided by flexural action, compression arch action, and catenary action. Among them, the contribution of compressive arch action was limited and can be ignored. Flexural action always provided the most structural resistance contribution in the whole impact process, and catenary action provided structural resistance under large deformation. The specimen structural resistance increased with increasing deformation before the failure of connections. Good flexural resistance and deformation capacity were the key factors for structures to resist impact load. The reversed channel specimen had the best impact resistance.

The Relation between Morphology of Maxillary Sinus after Augmentation in Three Classification Methods and Residual Bone Height: A Retrospective Study.

Maxillary sinus augmentation is critical to oral implantology, particularly in some cases. The morphology of the sinus floor reflects the lifting effect to a certain extent; however, there has been limited research on the morphology after sinus augmentation. The present study aims to investigate the relationship between residual bone height (RBH) and the morphology of the sinus floor and determine whether a correlation exists between the different evaluation classifications. Maxillary sinus floor augmentation procedures were performed in 56 patients and 68 teeth using the sinus crest approach (SCA). Imaging results obtained after one year of sinus augmentation were analyzed and simultaneously classified along the coronal plane, the sagittal plane, and the biplane (coronal-sagittal). The higher the RBH, the closer the result tends to be to A, A', or type 1 (more satisfactory). There was a significant correlation between the three different evaluation classifications (p < 0.05). The morphology of perforation cases was involved in types C, D, C', and D'. A more satisfactory post-lifting morphology (tent type and flat type) is probably related to an optimal preoperative bone height, and an unsatisfactory post-lifting morphology is related to a low preoperative sinus floor height. The sagittal plane evaluation correlates with the coronal plane and biplane evaluation and is thus more recommended.