Design and Construction Technology of Prefabricated Reinforced Concrete Slab Culverts

Compared with traditional cast-in-situ concrete slab culverts,prefabricated reinforced concrete slab culverts can be produced more quickly and has strong quality controllability,strong earthquake resistance,and repeatability.They will be the primary production method of slab culverts in the future.This article offers a comprehensive review of the design and construction technology associated with prefabricated reinforced concrete slab culverts.The objective is to provide a valuable reference for related enterprises,enhance the quality of design and construction in precast pile configuration,and,in turn,contribute to the advancement of construction projects within our country.

Suburban Sightseeing Farm Design from the Perspective of Behaviordriven Design

Suburban sightseeing farm has always been restrained by such problems as focusing on form and visual effect, low design level, poor depth, similarity with others, poor sustainability and so on. This paper proposed major characteristics of sightseeing farm design based on core connotations of behavior-driven design from the perspective of cognitive psychology. Cases were taken to analyze the design techniques of sightseeing farm, and it was concluded that sightseeing farm design based on behavior-driven perspective should orient to performancebased, refi ned, individualized and participatory from the four perspectives of highlighting functions, deepening the details, stressing originality, and optimizing experience, in order to provide new thoughts for solving existing problems of current sightseeing farm design.

NEW APPROACH FOR RELIABILITY-BASED DESIGN OPTIMIZATION:MINIMUM ERROR POINT

Conventional reliability-based design optimization （RBDO） requires to use the most probable point （MPP） method for a probabilistic analysis of the reliability constraints. A new approach is presented, called as the minimum error point （MEP） method or the MEP based method, for reliability-based design optimization, whose idea is to minimize the error produced by approximating performance functions. The MEP based method uses the first order Taylor＇s expansion at MEP instead of MPP. Examples demonstrate that the MEP based design optimization can ensure product reliability at the required level, which is very imperative for many important engineering systems. The MEP based reliability design optimization method is feasible and is considered as an alternative for solving reliability design optimization problems. The MEP based method is more robust than the commonly used MPP based method for some irregular performance functions.

Interval design point method for calculating the reliability of structural systems

The evaluation of reliability for structural system is important in engineering practices.In this paper,by combining the design point method,JC method,interval analysis theory,and increment load method,we propose a new interval design point method for the reliability of structural systems in which the distribution parameters of random variables are described as interval variables.The proposed method may provide exact probabilistic interval reliability of structures whose random variables can have either a normal or abnormal distribution form.At last,we show the feasibility of the proposed approach through a typical example.

Estimation for Partially Linear Models with Missing Responses:the Fixed Design Case

Suppose that we have a partially linear model Yi = xiβ ＋ g（ti） ＋εi with independent zero mean errors εi, where （xi,ti, i = 1, ... ,n} are non-random and observed completely and （Yi, i = 1,...,n} are missing at random（MAR）. Two types of estimators of β and g（t） for fixed t are investigated： estimators based on semiparametric regression and inverse probability weighted imputations. Asymptotic normality of the estimators is established, which is used to construct normal approximation based confidence intervals on β and g（t）. Results are reported of a simulation study on the finite sample performance of the estimators and confidence intervals proposed in this paper.

Single point and asymmetric incremental forming

This paper presents an update on single point incremental forming （SPIF） of sheet metal since 2005. It includes a description of the process with new information on the maximum forming angle, Фmax, for 5052-H32. An indepth example of the successful design and production of parts is given for industry. This includes discussion on production times and surface roughness with details that will help designers. A general design guide for users of SPIF is provided. It is based upon experience gained in the last decade. In general, materials show a trend of decreasing formability with increasing initial thickness. It is shown that for thicker sheet metal, it is recommended using large spherical tools （12.7 mm or larger）, or a large fiat-ended tool. The fiat-ended tool provides the best combination of good formability and very low surface roughness. For aluminum, galvanized steel and stainless steel, it is recommended using a fiat-ended tool. Advances in multi-pass techniques and information on successful and useful numerical models which predict forming behaviour are included. Finally, there is a discussion on future work needed in SPIF.

Numerical simulation of the three-dimensional flow-path in a ram-rotor

A kind of three-dimensional flow-path of the ram-rotor was designed in this paper according to the design method of the typical supersonic intake of aircraft and missiles,especially the design method of the compression ramp,the throat and the subsonic diffuser.The design Mach number of the flow-path was based on the averaged relative Mach number,regardless of the change of incoming Mach number along radial direction of the flow-path.Then,the flowfield of the designed flow-path was simulated numerically with computational fluid dynamics software at design point.The purpose of simulation was to obtain the details of the flowfield,including the structure of the shock wave system,position of flow separation zone,and so on.The performance of the ram-rotor was also evaluated.The numerical results show the structure of the shock wave system in the flow-path is similar to that in the supersonic intake.To improve the overall performance of the ram-rotor,the reasonable compromise between the total pressure ratio and the isentropic adiabatic efficiency should be reached.The structure optimization of the flow-path and the configuration of the shock wave system have great influence on the performance of the ram-rotor.

Local Homography Estimation on User-Specified Textureless Regions

This paper presents a novel deep neural network for designated point tracking(DPT)in a monocular RGB video,VideoInNet.More concretely,the aim is to track four designated points correlated by a local homography on a textureless planar region in the scene.DPT can be applied to augmented reality and video editing,especially in the field of video advertising.Existing methods predict the location of four designated points without appropriately considering the point correlation.To solve this problem,VideoInNet predicts the motion of the four designated points correlated by a local homography within the heatmap prediction framework.Our network refines the heatmaps of designated points through two stages.On the first stage,we introduce a context-aware and location-aware structure to learn a local homography for the designated plane in a supervised way.On the second stage,we introduce an iterative heatmap refinement module to improve the tracking accuracy.We propose a dataset focusing on textureless planar regions,named ScanDPT,for training and evaluation.We show that the error rate of VideoInNet is about 29%lower than that of the state-of-the-art approach when testing in the first 120 frames of testing videos on ScanDPT.