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To develop a 3D U-Net-based model for the automatic segmentation of the pancreas using the diameters, volume, and density of normal pancreases among Chinese adults.A total of 2778 pancreas images (dataset 1) were retrospectively collected and randomly divided into training (n = 2252), validation (n = 245), and test (n = 281) datasets. The segmentation model for the pancreas was constructed through cascaded application of two 3D U-Net networks. The segmentation efficiency for the pancreas was evaluated by the Dice similarity coefficient (DSC). Another dataset of 3189 normal pancreas CT images (dataset 2) was obtained for external validation, including 1063 non-contrast images, 1063 arterial phase images, and 1063 portal venous phase images. The pancreas segmentation in dataset 2 was assessed objectively and manually revised by two radiologists. Then, the pancreatic volume, diameters, and average CT value for each phase of pancreas images in dataset 2 were calculated. The relationships between pancreas volume and age, sex, height, and weight were analyzed.In dataset 1, a mean DSC of 0.94 for the test dataset was achieved. In dataset 2, the objective assessment yielded a 90% satisfaction rate for the automatic segmentation of the pancreas as external validation. The diameters of the pancreas were 43.71-44.28 mm, 67.40-68.15 mm, and 114.53-117.06 mm, respectively. The average pancreatic volume was 63,969.06-65,247.75 mmThe pancreas segmentation tool based on deep learning can segment the pancreas on CT images and measure its normal diameter, volume, and CT value accurately and effectively.

An accurate head-related transfer function can improve the subjective auditory localization performance of a particular subject. This paper proposes a deep neural network model for reconstructing the head-related transfer function (HRTF) based on anthropometric parameters and the orientation of the sound source. The proposed model consists of three subnetworks, including a one-dimensional convolutional neural network (1D-CNN) to process anthropometric parameters as input features and another network that takes the sound source position as input to serve as a marker. Finally, the outputs of these two networks are merged together as the input to a third network to estimate the HRTF. An objective method and a subjective method are proposed to evaluate the performance of the proposed method. For the objective evaluation, the root mean square error (RMSE) between the estimated HRTF and the measured HRTF is calculated. The results show that the proposed method performs better than a database matching method and a deep-neural-network-based method. In addition, the results of a sound localization test performed for the subjective evaluation show that the proposed method can localize sound sources with higher accuracy than the KEMAR dummy head HRTF or the DNN-based method. The objective and subjective results all show that the personalized HRTFs obtained using the proposed method perform well in HRTF reconstruction.

A new method of head-related transfer function (HRTF) personalization was built to optimize new user matching in the HRTF database to enhance 3D virtual hearing. The method of modified sparse representation (MSR) treated the HRTF personalization for an incomer as the task of finding similar subjects in the HRTF database with sparse representation (SR) of the incomer’s anthropometric features under the assumption that the equivalent sparse combination expresses the same anthropometric features and HRTFs for virtual hearing. The correlations among principal component coefficients and all anthropometric parameters were calculated after principal component analysis of the HRTF database for the same orientation. A derived database of anthropometric parameters was reconstructed, and SR was performed for all subjects in the original HRTF database. When the SR of the incomer was best matched with that of a subject in the derived database, the HRTF of the matched subject was used for the incomer’s 3D virtual hearing. The effect of MSR HRTF personalization was evaluated by spectral distortion. The results showed that the proposed method performed better than the others with the Chinese pilots database and the CIPIC database, especially in the frequency range of 0–8 kHz.

Objective This study aimed to investigate the use of three-dimensional visualization for preoperative evaluation of portal vein invasion in hilar cholangiocarcinoma (HCCA). Methods This recombination study for preoperative computerized tomography images was completed in 42 patients undergoing radical resection of HCCA combined with hepatectomy. Portal vein invasion with postoperative pathology was used as a gold standard to decide if the diagnosis was correct or not. We compared the sensitivity, specificity, positive predictive value, negative predictive value, and total correctness of radiologists and a three-dimensional (3D) visualization model for the assessment of tumor-caused portal vein invasion. Results The findings for the estimation of portal vein invasion by radiologists based on CT images were as follows: sensitivity = 90.9%; specificity = 83.8%; positive predictive value = 66.7%; negative predictive value = 96.3%; and overall accuracy = 85.7%. The findings for estimation by the 3D visualization model were as follows: sensitivity = 90.9%; specificity = 96.8%; positive predictive value = 90.9%; negative predictive value = 96.8%; and overall accuracy = 90.5%. Conclusion The positive predictive value of 3D visualization technology in the diagnosis of portal vein invasion is notably superior to that of subjective assessment by radiologists. This technique can thus play a significant role in preventing unnecessary resectioning of non-invaded portal veins and hepatectomy.

To compare the image quality of breath-hold magnetic resonance cholangiopancreatography (BH-MRCP) and respiratory-gating MRCP (RG-MRCP), and to explore breathing curve-based factors and patient-related data affecting image quality.A total of 126 participants who underwent RG-MRCP and BH-MRCP on a 3-T magnetic resonance (MR) scanner were enrolled from May to December 2021. The images were evaluated by three radiologists on a 5-point scale. Respiratory parameters were extracted from the breathing curves. The Wilcoxon test was used to compare the image quality between the two MRCPs. Logistic regression analyzes were performed to identify age, sex, abdominal pain, and breathing predictor variables of better image quality.BH-MRCP performed better in visualizing intrahepatic bile ducts and overall image quality than RG-MRCP (p0.01). Factors predicting relatively good image quality included lower standard deviation of the respiratory amplitude (SDBH-MRCP had significantly better overall image quality than RG-MRCP. Respiratory conditions exerted a significant impact on MRCP image quality, and parameters derived from the breathing curve could help predict the image quality of both sequences.• Both breath-hold (BH) and respiratory-gating (RG) MRCP demonstrate satisfying image quality. • BH-GRASE-MRCP is significantly better than RG-MRCP at the group level, but not for every individual. • Respiratory conditions exert a significant impact on the image quality, and the breathing curve can help predict the image quality.

There were totally 1749 scientific papers published in proceedings of conferences on Man-Machine-Environment System Engineering (MMESE) during 1993 to 2020 since the MMESE was founded in 1981 by guidance of Xuesen Qian with system engineering thought. The results were found by data analysis that 27.90%, 10.29%, 9.26%, 9.89%, 11.78%, 2.69%, 20.01% of the papers were in the subdomains of MMESE named as the Man Character, the Machine Character, the Environment Character, the Man-Machine Relationship, the Man-Environment Relationship, the Machine-Environment Relationship, the Overall Performance of Man-Machine-Environment System in addition to 7.66% under title of Theory and Application Research and 0.51% of Pandect. In the last decade, MMESE went much faster especially in 5.75% growth on the Machine Character, and trend was better and better for internationalization with efforts of main contributors such as the first authors of the papers, publishers, and MMESE committee of SESC.

Personalization of head-related transfer functions (HRTFs) is an essential task in the research on virtual hearing. In this paper, a method based on sparse principal component analysis (SPCA) and sparse representation (SR) was proposed to personalize HRTFs. The fundamental assumption is that an equivalent sparse combination can express the same anthropometric parameters. SPCA was first used to reduce the dimensionality of three-dimensional anthropometric parameters, and the reduced physiological parameters were used to reconstruct a physiological parameter database. SR was performed on the reconstructed physiological parameters of all subjects. For each subject, SR was used on the anthropometric parameters that were consistent with those in the reconstruction database. The matching pursuit algorithm was used to obtain the subjects in the database that had the same SR as the subject, and the HRTFs of the matched subject were used as the HRTFs of the new subject. The effect of the proposed method was evaluated by spectral distortion. The results showed that the method did better than others regardless of whether the Chinese pilots’ database or the CIPIC database was used, especially in the 0–8 kHz bandwidth.

This paper provides an individualization approach for head-related transfer function (HRTF) in arbitrary directions based on deep learning by utilizing dual-autoencoder architecture to establish the relationship between HRTF magnitude spectrum and arbitrarily given direction and anthropometric parameters. In this architecture, one variational autoencoder (VAE) is utilized to extract interpretable and exploitable features of full-space HRTF spectra, while another autoencoder (AE) is employed for feature embedding of corresponding directions and anthropometric parameters. A deep neural networks model is finally trained to establish the relationship between these representative features. Experimental results show that the proposed method outperforms state-of-the-art methods in terms of spectral distortion.

Objective This study aimed to investigate the use of three-dimensional visualization for preoperative evaluation of portal vein invasion in hilar cholangiocarcinoma (HCCA). Methods This recombination study for preoperative computerized tomography images was completed in 42 patients undergoing radical resection of HCCA combined with hepatectomy. Portal vein invasion with postoperative pathology was used as a gold standard to decide if the diagnosis was correct or not. We compared the sensitivity, specificity, positive predictive value, negative predictive value, and total correctness of radiologists and a three-dimensional (3D) visualization model for the assessment of tumor-caused portal vein invasion. Results The findings for the estimation of portal vein invasion by radiologists based on CT images were as follows: sensitivity = 90.9%; specificity = 83.8%; positive predictive value = 66.7%; negative predictive value = 96.3%; and overall accuracy = 85.7%. The findings for estimation by the 3D visualization model were as follows: sensitivity = 90.9%; specificity = 96.8%; positive predictive value = 90.9%; negative predictive value = 96.8%; and overall accuracy = 90.5%. Conclusion The positive predictive value of 3D visualization technology in the diagnosis of portal vein invasion is notably superior to that of subjective assessment by radiologists. This technique can thus play a significant role in preventing unnecessary resectioning of non-invaded portal veins and hepatectomy.

The temperature of domestic drain water is relatively high, but its flux is sometimes insufficient as a heating source. Thus, the conventional wastewater source heat pump water heater is incapable of meeting user heating demand given the limited sensible heat temperature difference in many situations. To address this problem, a novel in–house heat pump water heater with a freezing latent heat evaporator and assisted by domestic drain water was proposed. A prototype of the system was first constructed to determine the performance of the system. An experiment was then conducted, in which a parallel helical coil tube evaporator was designed and developed to extract freezing latent heat from domestic drain water. Experimental data was obtained in different experimental conditions. Results of the investigation show that the heat pump water heater with a freezing latent evaporator recovers 3.4 times more energy than the conventional wastewater source heat pump water heater, and saves 60% energy compared with the traditional electric water heater. Furthermore, an interesting result is that the heat transfer coefficient increased significantly at the moment the wastewater was just frozen. This paper provides a reference for the wastewater source heat pump water heater to extract freezing latent heat from domestic drain water.

An array arrangement strategy of photovoltaic thermal modules and a connection form of refrigerant pipeline were innovatively proposed by author’s research group. Subsequently, the photovoltaic thermal heat pump system engineering was designed and constructed, and then the performance study of system heating in continuous operation and stage operation in winter was carried out in January 2021. During the system operation, the average coefficient of heating performance of the system was 2.95 in daytime stage operating, 2.55 in nighttime stage operating and 2.07 in continuous operating. To conduct the application simulation of photovoltaic thermal heat pump system, first the prediction model of system heating performance based on back propagation neural network was established and verified according to the operational parameters, then 12 cities of typical climate zone in China were selected to conduct operation simulation and performance prediction to analyze the regional applicability of the system, finally the performance prediction of system heating under variable working conditions was carried out to guide the design calculation of engineering application of photovoltaic thermal heat pump system engineering. It can be concluded that the system was more suitable for engineering application in cities of cold zone and hot summer and cold winter zone than that in severe cold zone. Besides that, the integration and operation optimization of system should be carried out to reduce the average temperature of the circulating hot water tank so that the energy efficiency of hot water system can be improved by 42%.

Actively promoting the reconstruction of clean heating is the key direction of the “Planning for clean heating in winter in northern China (2017–2021)”. The photovoltaic thermal heat pump system was introduced in this paper to improve the comprehensive energy efficiency and reduce the operation energy consumption of the heat source system, which provided a new idea for the energy saving reconstruction of clean district heating. In order to verify the feasibility of the energy saving reconstruction by photovoltaic thermal heat pump, following studies were carried out in this paper: First, the integrated energy system engineering based on photovoltaic thermal heat pump was constructed to study the heating performance of the system in winter. Subsequently, the prediction model of heating performance based on back propagation neural network was established and optimized to simulate the heating performance throughout the year. Then, the calculation model of district heating system was established and the evaluation method of system operation energy efficiency and economic performance based on “equivalent electricity consumption of heating” was introduced. Finally, a residential area of Dalian was taking as an example to study the economic performance of energy saving reconstruction of district heating system based on three conventional heat sources by photovoltaic thermal heat pump. The results showed that after the capacity expansion and energy saving reconstruction based on photovoltaic thermal heat pump were conducted, the payback period of energy saving reconstruction investment was 5 years. Besides, with the increase of the configuration ratio of photovoltaic in the system from 1 to 2, the payback period was further shortened to 3 years.

The condensates generated in the process of film condensation, such as condensing, falling, and acting condensates, are identified and defined to obtain precise inundation effect model of 3D finned tube bundle. Furthermore, the influence of three categories of condensates on the film condensation under different heat fluxes and condensing temperatures is experimentally investigated via the homologous method. A test bench with a test section contains two arrays of 8 horizontal tubes is initially constructed. Experimental results show that the inundation effect coefficient decreases from 1.00 to 0.78 as acting condensate Re increases from 75 to 1860. The influence of heat flux on three categories of condensates is more significant than that of condensing temperature. As tube row depth increases from 1 to 6, the proportion of condensing condensate Re to acting condensate Re decreases from 100% to 15.0%, whereas the proportion of falling condensate Re to acting condensate Re increases from 0 to 85.0%. Furthermore, the condensation heat transfer model of single 3D finned tube and inundation effect model are established, and the deviations of results between experiments and models are almost within ±3.0%. The deviations of inundation effect coefficients between experiment and model proposed in this study are 92.5% and 50.0% less than those between experiment and models using routine method and considering single condensate with homologous method, respectively. Moreover, the inundation effect model proposed in this study reveals that different proportions of condensing or falling condensates to acting condensate lead to different inundation effect coefficient at the same acting condensate Re. The research results will lay the foundation for further revealing the mechanism of film condensation on 3D finned tube bundle and guide the thermal design of 3D finned tubes applied in shell-and-tube condensers.

A specified procedure was conducted for measuring HRTF database. The experimenters were trained to reduce the tester errors. Pilot as participator was sat in (x, y, z) coordinates with the origin at midpoint of bitragion on his Frankfurt plane same as polar coordinates of (r, ϕ, θ), keeping his posture to reduce the testee errors during each block of the experiment. The test–retest checks were arranged at (ϕ, 0°), (ϕ, 180°) and (ϕ, 360°) for data quality control. Other strategies were done such as the division of the experiment into 13 blocks and schedules of rest by turns to reduce human errors from fatigue. Three testers were trained with dummy head MK2B, and 63 male pilots were measured in hemi-anechoic room to build CHNAF HRTF database. The results were found that the tester error was about 0.29 dB of ILD and –0.75° azimuth deviation, the 2.0 dB of ILD was acceptable alarm threshold for binaural spatial symmetry because of pilots posture change, and the data quality of the CHNAF HRTF database was well validated.

Objective—To study the color requirements of displayed information in see-through displays when pilots flying in the desert. Methods—The experimental materials included some route and combat flight menus. There were eight fixed colors and custom colors provided to be chosen. The experimental procedure was programmed. One hundred and fifteen fighter pilots participated in the study. They were required to choose the most suitable colors for the display elements in the menus. Results—(1) For the two types of menus, the numbers of pilots that chose colors for the same information elements were generally consistent. The number of pilots choosing green was superior in most long-time displayed information elements including normal information. (2) For the information of flight element category and flight instruction category, the numbers of pilots choosing green and choosing blue were generally equal. For the dangerous information, unattackable information and overrun information with unlong-time displayed information, the number of pilots choosing red was superior. And for the information that was latent dangerous, the number of pilots choosing yellow was superior. Conclusions—When flying in the desert, pilots have evident requirements of colorful displayed information for see-through displays. Their requirements were as follows: The main color was green. The long-time displayed and normal and attackable information was tended to be displayed in green. The dangerous, unattackable and overrun information was tended to be displayed in red. And the latent dangerous information was tended to be displayed in yellow.

This study aims to evaluate effectiveness of several psychological measures from Vienna Test System. Method A total of 110 male pilot candidates complete Chinese pilot selection psychological test battery and five measures from Vienna Test System. Spearman correlation was used to evaluate the effectiveness of the measures. Results: Spearman correlation analysis results reveal that total score of Chinese selection systems significantly correlate to seven indexes drived from five VTS subtest respectively (r = 0.250–0.508, P < 0.05) expect correct numbers of Pilot’s Spatial Test. Conclusion: In this study, we test the effectiveness of five measures from VTS in Chinese pilot candidate selection. These five measures are all consistent with our system and be conducive to improvement of selection system.

The 3D head anthropometry of 69 Chinese male pilots was tested in order to build China Air Force head-related transfer function (HRTF) database, i.e. CHNAF HRTF Database in abbreviation. There were totally 93 anthropometric landmarks defined according to principles of physical acoustic reflection and refraction. All the landmarks were measured in sitting with (x, y, z) coordinate system to get 2D dimensions in GB/T 5703/ISO 7250-1 and GJB 4856 and 3D descriptions of the head with polar coordinate transformation in (r, ϕ, θ). The test results of the 3D descriptors showed the 3D positions of anatomical mediators between the outer acoustic signal and pilots’ auditory spatial localization, in which there were 50 landmarks about ears or auricle, 33 landmarks about skull, eyes, face and noses and 10 about neck and shoulders. Therefore, the CHNAF HRTF Database could provide about 150 items of anthropometric measurements for HRTF and its personalization especially with focus on the role of ears.

Objective: To develop an evaluation system on the emergency coping ability that is very important for effective performance in many emergency or extremely tasks, especially in aviation. Methods: An evaluation system and related hardware on emergency coping ability based on continuous tracking task and psychophysiology measurement were developed. The reversed operation was used to provide emergency situation. A total of 13 pilots completed the continuous tracking task. Performance which was measured by the average distance deviated from the target track and heart rate, heart rate variability indexes were recorded by the system and were analyzed for the validity. Results: Tracking performance of norm tracking task are significantly higher than those of different reversed tracking phases, especially that of the first six seconds. The participants adapted to the reversed operation gradually after 6 s. Mean heartbeat rate and LF/HF ratio also increased in reversed tracking phase. Conclusions: Index of emergency coping ability could be derived from the difference between tracking performance and psychophysiology change of norm tracking task and reversed tracking phase. The emergency situation model and evaluation system were developed and validated.

Ergonomics evaluation of aircraft cockpit interface is the way to apply human-centered design philosophy. This study aims to explore Ergonomics evaluation method based on eye tracking technology which could be used in UVA control station. Methods A total of 31 operation tasks were developed and each one aimed at one function unit of the UVA system. Ergonomics evaluation by eye tracking technology and expert subjective analysis were both done to diagnose the design problems. A total of 12 male UVA pilots participated in the experiment. Results A total of 13 units were diagnosed as low level by eye tracking method, while 14 units were evaluated as low level by subjective evaluation. McNemar test results show that the difference between two methods was not significant (P > 0.05). One-way ANOVA test shows pupil diameter of low-level Ergonomics tasks was significantly longer than that of the high-level task (P < 0.05). Conclusion Combination of two methods was the practical Ergonomics evaluation method in UAV control station interface.

Objective: To verify the superiority of colorful display schemes proposed by authors before for see-through display information. Methods: 67 Chinese male pilots finished flight and combat tasks in two colorful schemes versus one monochrome scheme with dynamic simulating flight procedure and then evaluated every scheme. Results: (1) There was superiority with several performance indexes in two colorful schemes. (2) For alerting information in colorful display schemes, their correct reaction times (CRTs) were shorter and faster than those in monochrome scheme. (3) In subjective evaluations, there were higher rate of excellent and good with several indexes in colorful schemes. Conclusions: There were superiority with some performance and subjective evaluation indexes in colorful schemes. The advantages were evident especially for the time of accomplishing identification of alerting information. The superiority of two colorful display schemes was verified in this study.

A color perception experiment was conducted to explore the color requirements of paratroopers for the interior decoration of transport cabin in military missions in order to determine the color design of transport aircraft. 392 male paratroopers in service were volunteered as subjects to choose their approved colors relative to their air-move missions on the basis of visual comparisons with two series of color palettes which are made by aerospace paint producer. The light series of color paint films were chosen for the cabin walls of structure, and the dark series was for the main controllers in the cabin, respectively. It was found that the light gray coded L002 and the monkey gray coded L004 got the top rank in the light color series of paint films while the concrete gray coded D001 was the top followed by the medium gray coded D008 in the dark color series to the exclusion of private color preference in daily life. The colors of paint film approved by paratroopers can be used for environment design of transport aircraft cabin.

The working eye position (WEP) of 256 Chinese male pilots were tested in simulated flight to determine the design eye position (DEP) of advanced fighter cockpit. Four WEPs were defined in that (1) WEP-C, i.e. the WEP with seated posture of cruise, (2) WEP-L, i.e. the WEP with oblique posture of left sway, (3) WEP-R, i.e. the WEP with oblique posture of right sway, and (4) WEP-G, i.e. the WEP with bowed posture of anti-G load in a simulated recurrences of their mission flight for level linear cruise or rapid maneuvers. The results were found that the WEP-L showed significantly about 30 mm left-shifting with 3 mm downward-shifting marginally, the WEP-R showed significantly about 40 mm right and 18 mm backward shifting with 3 mm downward-shifting, and the WEP-G showed significantly about 10 mm downward-shifting in contrast with the WEP-C. The DEP should be pointed at (0,125,755) in (x, y, z) above neutral seat reference point (NSRP) based on WEPs of pilots rather than point (0,155,795) in GJB35B, and the HUD design eye box (DEB) may be in size of 340 mm wide, 195 mm high, and 470 mm deep better than 340, 185, and 415 mm without the WEP-G.

To develop a radiomics model in the preoperative differentiation of mucinous cystic neoplasm (MCN) and macrocystic serous cystadenoma (MaSCA) and to compare its diagnostic performance with conventional radiological model.57 Patients (MCN = 31, MaSCA = 26) with preoperative multidetector computed tomography (MDCT) scans were retrospectively included in this study. A radiological model was constructed from radiological features evaluated by radiologists. A radiomics model was constructed with high-dimensional quantitative features extracted from manually segmented volume of interests (VOIs). A combined model was constructed using both radiomics features and radiological features. The diagnostic performance of three models were assessed by the area under the receiver-operating characteristic curve (AUC), sensitivity, specificity, accuracy, and the calibration curves.The radiological model yielded an AUC of 0.775, sensitivity of 74.2 %, specificity of 80.8, and accuracy of 77.2 %. The radiomics model yielded an AUC of 0.989, sensitivity of 93.6 %, specificity of 96.2 %, and accuracy of 94.7 %. The combined model yielded an AUC of 0.994, sensitivity of 96.8 %, specificity of 100 %, and accuracy of 98.2 %. Both combined model and radiomics model showed higher AUC, sensitivity, and accuracy than radiological model (all P .05). The combined model showed higher AUC than radiomics model, though no significant difference was found (P = .41). The combined model showed better calibration than radiomics model (P = .91 vs. P .001).Combined model which contained both radiomics features and radiological features outperformed radiomics model and radiological model in the preoperative differentiation of MCN and MaSCA.

To accurately evaluate the condensation heat transfer performance of new 3D finned tubes in shell-and-tube condenser, the inundation effect of the film condensation of R-134a on an array of 6 horizontal new 3D (three-dimensional) finned tubes is experimentally investigated with a new experiment method of homologous method. And the precise inundation effect coefficient of film condensation is determined. A novel test facility, whose test section contains two arrays of 8 horizontal tubes to realize the homologous method, is developed and constructed. The outer diameter of the tube and effective tube length in the test section are 19.05 and 500 mm, respectively. The condensation heat transfer coefficient of new 3D finned tube and inundation effect coefficient of new 3D finned tube bundle are determined under different conditions. The results show that the inundation effect coefficient of new 3D finned tube bundle decreases from 1.00 to 0.78 as Re increases from 75 to 1860. And the effect of heat flux on the inundation effect is more sensitive than the condensing temperature. Furthermore, for new 3D finned tube, the condensation heat transfer and inundation effect models are established, and the deviations of results between experiment and models are almost within ±6.0%. In comparison with literatures, the average inundation effect coefficient of new 3D finned tube bundle is 10.0-25.0% higher than that of 3D finned tube bundle in literatures, within 3.0% lower than that of two-dimensional finned tube bundle, and 15.2% higher than that of plain tube bundle. And the average condensation heat transfer coefficient of new 3D finned tube bundle in this article is 5.0-25.0% higher than that of 3D finned tube bundle in literatures, 10.0-30.0% higher than that of 2D finned tube bundle, and more than 10 times that of plain tube bundle. The precise inundation effect coefficients can be used as benchmark data to build precise and universal inundation effect model of 3D finned tube, and the models established in this study will help guide the thermal design of the new 3D finned tube applied in shell-and-tube condenser.

Heat pumps are a part of the environmentally friendly technologies using renewable energy and have been utilized in HVAC systems. A heat pump water heater unit with frozen type evaporator was designed and developed. And a test bed was constructed to determine the performance of the unit. In the experiment, a parallel helical coil type evaporator was used in the unit to extract latent heat from the sewage. The data (dynamic COP and other parameters) was obtained in three processes(including the first freezing, melting, and the second freezing) at different water temperatures (8.2℃ and 13.8℃). Results show that compare with traditional water source heat pumps, the newly designed unit with the frozen evaporator can reduce the required water amounts as a heat source by more than 90%. The higher initial temperature of hot water and sewage, the higher temperature of sewage after melting. Meanwhile, with the increase of the initial temperature of hot water and sewage, the comprehensive COP was greater. This paper will provide a reference for the sewage source heat pump system to extract the latent heat from the sewage.

Emotional analysis of text has always been a hot topic in natural language research. In view of the long-term dependence of recurrent neural networks and the fact that most models do not consider the correlation between input and output, this paper proposes a bidirectional LSTM model based on attention mechanism to judge the comment emotion. This method vectorizes the semantics of comments into the LSTM model, improves the relevance of input and output through the attention mechanism, fuses the aspect category and aspect Term, and outputs the results through the classifier. The experimental results of Dianping.com review data set provided by AI Challenger competition show that the improved method adopted in this paper is better than the common deep learning method.

Employee training is not only important for the continuous growth of human resources but also guarantees sustainable human resource management in enterprises. It is very important to understand corporate behaviour related to employee training not only from the perspective of a single enterprise but also from that of multiple enterprises. The purpose of this study is to explore multiple enterprises’ employee training behaviours by conducting a content analysis of corporate social responsibility (sustainability) reports and a social network analysis. This study also seeks to find a way to achieve sustainable employee training by analysing the similarities in the different types of corporate training behaviours. Our analysis shows that, in 2017, 108 types of training activities were implemented by 53 enterprises, the key employee trainings (e.g., security training and skills training) and enterprises (e.g., bank of communication) are identified. The training behaviours of some of the enterprises are similar to some extent, and eight groups of firms that are very similar are identified. The results of this study show that social network analysis performs well for studying corporate employee training behaviours. Some suggestions to minimize the investment costs of training and to improve the sustainability of human resource management from the employee training perspective are provided.

A novel integrated home energy system with freezing latent heat collection was proposed to improve the overall efficiency of building energy usage. The novel unit can recycle waste heat (including sensible and freezing latent heat) from domestic drain water and condensing heat to efficiently provide space heating and cooling and domestic hot water for a household. A novel unit, whose core equipment was a parallel serpentine tube evaporator with a new de-icing technique to efficiently extract freezing latent heat, was initially constructed. The performance, annual thermal energy recycling rate, and life cycle cost of the novel unit were determined, studied, and discussed, respectively. Results showed that the coefficient of performance of the unit with de-icing technology is 10.00−20.00% higher than that of systems reported in extant literature under unfavorable condition. The annual thermal energy recycling rate was 25.00−30.00%, which is approximately 2.6 times that of systems described in literature. In addition, the life cycle cost of the unit is 10.00−35.00% lower than that of traditional units. The novel unit considerably reduces the energy consumption, environmental pollution, and related costs of buildings, thus providing practical importance and a scientific research value for improving energy efficiency, changing the original energy structure, and reducing the environmental load brought by energy conversion.

An experiment was conducted to research the optimal position of heading information in display formats of fighter HUD. Two display formats were programmed according to the guidelines in ARP5288 or the “Basic T” arrangement in AC25-11B, i.e. display format (a) in which heading information were located on the attitude, and display format (b) in which heading information were positioned below the attitude. In the present study, 151 pilots participated in user performance test in context of simulated A/A and A/G flight tasks for heading information reading and state judgment of aircraft based on the display formats. The results were that the main effect of display formats was marginally significant for CR (P = 0.05) and very significant for CRT (P < 0.001). The display format (b) was maybe slightly better than that of display format (a), or both of the display formats were compatible. The pilots preferred the display format (a) to (b) in a vote (about 98% vs. 30%) after experimental uses, although the display format (b) might be cognized slightly faster than the display format (a). Other findings were also discussed.

A two-step subjective rating technique was constructed to refine and validate the responses of pilots in Q–Q test for aircraft cockpit as a means of subjective data collection and problem diagnosis of designs on the bases of pilot judgment from points of user’s view in the context of simulated flight tasks. Twelve male pilots participated in the Q–Q test for pilot evaluation of a new cockpit prototype as 5th, 50th or 95th percentile representatives in stature. Each user made a judgment firstly about the tested design on the index with acceptability scale and then indicated the deficiencies in the design or the problems in use they found if they complained as “not acceptable” or “not satisfactory” in satisfaction scale, while pilot comments were verified. It is not allowed that only a level or rating score was made without a problem arising because the list of questions is very important as well as suggestions for improvement in Q–Q test. The final list of questions and suggestions was based on the consensus of users, but how to improve is the responsibility of the designer. The results and the influences were also discussed.

Objective To study the simulated flight performance with monochrome and colorful display for see-through displays, and propose the best color scheme of information. Methods Ninety-one fighter pilots participated in the experiment. In virtue of monochrome and colorful display effects experimental procedure for see-through displays information in fighters, pilots finished simulated flight and combat tasks, respectively, in six color schemes and evaluated every color scheme after the simulated tasks. Results (1) In the simulated tasks, the performance indexes were not significant in six color schemes. (2) In monochrome scheme (scheme No. 1), it was not propitious for pilots to rapidly identify and response to the alerting information when they displayed in green, and there was more advantages when displayed in red and yellow (scheme No. 3 and No. 5). (3) In subjective evaluations, scheme No. 2 was evaluated better, and scheme No. 3 was in the next place. Conclusions The scheme No. 2 and No. 3 were recommended as the best color schemes, but this conclusion was only primary, and verifying researches should be conducted later.

Eye-tracking technology was used to study the visual sensitive area and the ergonomics of commonly used information encoding methods in large screen primary flight display (PFD) in order to optimize the interface design. Methods A total of 44 pilots (36 ± 6 years) attended the experiment. Seven typical flight human–machine interface images were adapted according to varied factors such as 12 quadrants, 6 colors, and 10 presentation encodings which would affect the ergonomics design. The pilots were asked to search a target picture with full information intercepted from the typical images, and the eye tracker was used to record the eye movement data during the task. The performance differences were analyzed among factors. Results The results of multivariate test showed that: (1) There are significant differences between 12 quadrants and 7 typical pictures (P < 0.01), and the interaction effect between pictures and quadrants is significant (P < 0.01). (2) There were significant differences among the 6 colors, 7 typical pictures, and 12 quadrants groups (P < 0.01); and the interaction among three factors were significant (P < 0.01). (3) There were significant differences among the 10 presentation encodings, 7 typical pictures, and 12 quadrants (P < 0.01). The interaction among three factors was significant (P < 0.01). Conclusion (1) The visual sensitive area of the large screen primary flight display is quadrant 1, 5, 7; the area of visual insensitivity is 10, 12. (2) According to colors, red was the optic color, yellow and green were the worst color. (3) According to presentation encodings, white character with white borders and white character with red shading borders are optic encoding, and black character with yellow borders and green shading was the worst.

Objective To investigate use requirements of pilots for inner color in aircraft cabin design. Methods Compared to the light and dark color system boards with rank-order method, 198 Chinese pilots participated in the experiment. Pilots were asked to rank 24 pieces of color boards according to the fitness as aircraft cockpit interior and select their favorite colors in daily life from standardized color cards. Results (1) In light color system, the lowest grades were E and C boards, and the highest grades were L and K. At the same time, the pilots’ favorite to 12 light colors had statistical significance (P < 0.001). (2) In dark color system, the lowest grades were E′, H′, and A′ boards, and the highest grades were L′ and K′. The pilots’ favorite to 12 dark colors had also statistical significance (P < 0.001). (3) Pilots’ favorite to daily colors had no significant effect on their choice in cockpit color. Conclusions Through the pilots’ comparing color boards and questionnaire investigation, the decorating colors that fit control devices and cabin walls in aircraft were proposed. Pilots’ favorite to daily colors had no effect on their choosing colors for cockpit decoration.

To investigate the risk factors and computed tomography (CT) diagnostic accuracy of anastomotic leakage after resection of rectal cancer (Dixon).This retrospective study was conducted in Peking University First Hospital from January 2013 to June 2015. A cohort of 452 patients with rectal cancer was enrolled in the study. All the patients underwent anterior resection. The relationship between clinical-pathological data (including sex, age, body mass index (BMI), presence of diabetes, hypohemoglobin (Hb90 g/L), hypoalbuminemia (Alb35 g/L), the distance from the lower edge of the tumors to the anus, tumor diameter, tumor differentiation, tumor TNM stage, neoadjuvant therapy status, ligation of the left colonic artery(LCA), preventive colostomy, and anastomotic leakage was analyzed retrospectively. Univariate analysis using χOf all the cases, 281 and 171 patients were men and women, respectively. The median age was 64 years (range, 18-88 years). Forty-seven patients (10.4%) were diagnosed with anastomotic leakage, and the median diagnostic time of anastomotic leakage was 6.5 days(range, 3-31 days). One patient with anastomotic leakage died because of respiratory failure within 1 month postoperatively; 11 patients underwent salvage colostomy performed 2-34 days (median, 7 days) after the first surgery. All the 11 patients underwent colostomy closure within 2 years. The other 35 patients recovered by antibiotic and peritoneal lavage treatment. The mean length of postoperative hospital stay in patients without anastomotic leakage was 8.4±2.4 days, which was significantly shorter than that in patients with anastomotic leakage (34.6±15.7 days), and the difference was statistically significant (t=24.127, P=0.008). The results of the univariate analysis showed that BMI≥28 kg/mImportant factors, including BMI of patients, LCA ligation, and the distance from the lower edge of the tumors to the anus are related with anastomotic leakage. The individual treatments should be considered based on the patient's clinical condition. CT was recommended 7 days postoperatively when anastomotic leakage was highly suspected.

Mental ability will decline by ageing while the experience accumulating. It is important to study the mental attributes of aged test pilots in order to maximum professional span and ensure flight safety. Methods A total of 35 experts including test pilots and aircraft design engineers were interviewed on the issues of the mental ability of aged test pilots through completing a questionnaire about the issue. A battery of mental ability test and 16PF were used to examine 37 test pilots who were divided into three age groups (age above 45 year, n = 16) and control group (age below 45 year, n = 21). Results Most important mental attributes of older test pilots were related to professional spirits, flying expertise (judgment) and personality. The firstly aging abilities were cognition and psychomotor ones. Scores of Detecting special graph, Distinguishing direction and Distracted listening were lower than those of control group (P < 0.05), which were negatively correlated to age (r = −0.335, −0.411, −0.409, P < 0.05). Conclusion Mental abilities related to reaction speed decline earlier. Although the expertise may compensate for the decline, routine aptitude test will benefit the increasing need for test pilot and aviation safety.

The purpose of the study was to find visual search characteristics on cockpit man–machine interface by the pilots with different flight experiences and different ages. Methods Test objects were 44 men; they were divided into three groups according to different aircraft cockpit experiences with large screen display or different age groups. The completely randomized block test was used. The instrument for recording eye movement was adopted in the process of eye-target search. Results Among 14 parameters for eye movement, 13 parameters were statistically significant (P < 0.05). Significant differences existed between groups of different experience background. There were seven indicators showed that the novice group was more than the expert group, the expert pilot group was greater than the mature group. The results of different age groups were as follows: Significant differences existed among three groups of different ages. Eight eye movement indicators showed that the values of 40–45-year-old group were more than that of 25–35-year-old group; the values of 25–35-year-old group were more than that of 35–40-year-old group. Conclusion The novice group was least familiar with screen layout and therefore search target took longer time and more fixation points. The expert pilot group is the most experienced in three groups, but they took more time to search targets than the mature group. The reason might be that “no error” thought forced them to confirm on the same issue repeatedly, resulting that the search efficiency was lower. Data of different age groups showed that the older the ages were the worse eye movement data were. This shows that as the increase of age the eye’s capture and search ability fall. But for some other indicators, 35–40-year-old group was better than that of 25–35-year-old group, indicating that there were interactions between the experienced background and ages because there were more novice pilots in 25–35-year-old group, familiarity of the picture can make up for the lack of physical reaction speed.

Objective To study the color coding requirements of displayed information in see-through displays during aeromarine fight. Methods One hundred and fifteen fighter pilots participated in the experiment. In virtue of color coding experimental procedure for see-through displays information in fighters, pilots selected colors for the display elements in the route and combat flight menu. Results (1) The pilots’ color coding requirements of flight course menu were that green was the main color, longtime displayed and normal information was inclined to be green, dangerous and overrun information was inclined to be red, and latent dangerous and needing pilots’ attention information was inclined to be yellow. (2) The pilots’ color coding requirements of combat menu were that green was the main color, longtime displayed and attackable information was inclined to be green, and unattackable and overrun information was inclined to be red. Conclusions The pilots’ color coding requirements for see-through displays in aeromarine flight were that green was the main color; longtime displayed and normal and attackable information was inclined to be green; dangerous, overrun, and unattackable information was inclined to be red; latent dangerous and needing pilots’ attention information was inclined to be yellow. Above conclusions were only primary, and subjective and objective researches should be conducted later, so as to deeply verify the rationality of pilots’ requirements.

An experiment was conducted to explore the optimal display format of target range for HUD of aircraft. An integrated display format with trigon attached to the target designator was defined and compared with a separable display format of fixed scale with level linear indicator. The cognitive tasks were of extractive task versus integrative task in simulated flight with 2 × 2 within-subject experiment design. There were 151 Chinese male pilots participating in the human factor test. Results were found that the integrated display format of target range was recognized much better and faster in performance of 7.61% increments in correct reaction and 1.16s decrements in correct reaction time compared with the separable format and approved by 90.76% of the pilots. The conclusion was made that the integrated display format of target range could improve cognitive performance of target range information in HUD of aircraft on the basis of discussion.

A comparative survey was conducted with 163 Chinese male pilots to build an anthropometric method based on computer graphics. 10 human body dimensions of point-to-point distance were gathered by extracted measurement based on computer graphic and traditional measurement in ISO7250 techniques. It was found that the extracted measurements were homogeneous with the traditional measurements in standardized Z scores, but there were systematic errors in raw data of the anthropometric method based on computer graphics. It suggested that the methodology based on computer graphics was well acceptable in views of ISO20685 because all mean differences were less than ±1.0 mm in 95% confidence interval after data correction by linear equation. Some factors were also discussed.