A Geometric Layout Method for Synchronous Pseudolite Positioning Systems Based on a New Weighted HDOP

The positioning accuracy of a ground-based system in an indoor environment is closely related to the geometric configuration of pseudolites. This paper presents a simple closed-form equation for computing the weighted horizontal dilution of precision (WHDOP) with four eigenvalues, which can reduce the amount of calculation. By comparing the result of WHDOP with traditional matrix inversion operation, the effectiveness of WHDOP of the proposed simple calculation method is analyzed. The proposed WHDOP has a linear relationship with the actual static positioning result error in an indoor environment proved by the Pearson analysis method. Twenty positioning points are randomly selected, and the positioning variance and WHDOP of each positioning point have been calculated. The correlation coefficient of WHDOP and the positioning variance is calculated to be 0.82. A pseudolite system layout method based on a simulated annealing algorithm is proposed by using WHDOP, instead of Geometric dilution of precision (GDOP). In this paper, the constraints of time synchronization are discussed. In wireless connection system, the distance between master station and slave station should be kept within a certain range. Specifically, for a given indoor scene, many positioning target points are randomly generated in this area by using the Monte Carlo method. The mean WHDOP value of all positioning points corresponding to the synchronous pseudolite layout is used as the objective function. The results of brute force search are compared with the method, which proves the accuracy of the new algorithm.

Geometric design of single-lane roundabouts for optimum consistency and operation

The objectives while designing roundabout is design consistency and operational performance. Design consistency affects roundabout safety while operational performance affects its level of service. Along with design consistency, roundabout will be more safe if its geometry forces traffic to enter and circulate at less than specified design speed. Vehicle path radii control speeds at each vehicle path. Vehicle path radii are traditionally obtained from drawing freehand each vehicle paths on proposed roundabout geometry. Existing design approaches for roundabouts use a trial-and-error procedure to choose the design parameters in order to satisfy design standards. With this approach it is quite complicated to satisfy design guidelines and site conditions at the same time. A minor change in geometry can result in significant changes in safety and operational performance. Therefore, many iterations of geometric layout would be required to evaluate safety and operational analysis at given traffic conditions. Designer needs to revise and refine the initial geometric layout to enhance safety and its operational performance. In this thesis, an optimization model is developed that predicts optimum design parameters with multiple objectives: maximum design consistency and minimum average intersection delay. At optimum design parameters, this model also provides vehicle path radii for each path. These vehicle path radii were used to predict operating speed along each path using an existing operating speed prediction model. The optimization model takes site conditions as input and satisfies the two objectives for given traffic and geometric conditions. This is a new approach of optimum design of single-lane roundabouts with four legs intersecting at right angle. The model not only satisfies the two objectives, but also limits the operating speed along each path (left, through, and right), below the specified design speed of roundabout.

Geometric design of single-lane roundabouts for optimum consistency and operation

The objectives while designing roundabout is design consistency and operational performance. Design consistency affects roundabout safety while operational performance affects its level of service. Along with design consistency, roundabout will be more safe if its geometry forces traffic to enter and circulate at less than specified design speed. Vehicle path radii control speeds at each vehicle path. Vehicle path radii are traditionally obtained from drawing freehand each vehicle paths on proposed roundabout geometry. Existing design approaches for roundabouts use a trial-and-error procedure to choose the design parameters in order to satisfy design standards. With this approach it is quite complicated to satisfy design guidelines and site conditions at the same time. A minor change in geometry can result in significant changes in safety and operational performance. Therefore, many iterations of geometric layout would be required to evaluate safety and operational analysis at given traffic conditions. Designer needs to revise and refine the initial geometric layout to enhance safety and its operational performance. In this thesis, an optimization model is developed that predicts optimum design parameters with multiple objectives: maximum design consistency and minimum average intersection delay. At optimum design parameters, this model also provides vehicle path radii for each path. These vehicle path radii were used to predict operating speed along each path using an existing operating speed prediction model. The optimization model takes site conditions as input and satisfies the two objectives for given traffic and geometric conditions. This is a new approach of optimum design of single-lane roundabouts with four legs intersecting at right angle. The model not only satisfies the two objectives, but also limits the operating speed along each path (left, through, and right), below the specified design speed of roundabout.

An Analysis of Turbo Roundabouts from the Perspective of Sustainability of Road Transportation

The designs of turbo roundabouts vary among countries and undesirable and potentially dangerous situations can occur for vehicles passing through the roundabout. In this article, we focus on an analysis of one of the problems within sustainable road transportation, i.e., the geometric layout of turbo roundabouts. First, we review the Czech and foreign regulations and describe the design procedures for turbo roundabouts. Studies that have been performed in the Czech Republic and abroad (the Netherlands, Slovenia, Poland, Germany, Hungary, etc.) are described. We evaluate the geometric layout of turbo roundabouts, the effectiveness of construction adjustments at the entrance to the roundabout, and an analysis of the physical separation of lanes. We present procedures and methods for measurements and assessments, which are used for evaluating the effectiveness of the geometry of a turbo roundabout. Finally, conclusions for the given hypotheses are given, as well as the importance of geometric elements (shape of the turbo roundabout, physical separation of lanes, the spike, etc.) for the actual passage of vehicles through the turbo roundabout. Furthermore, we discuss how these elements influence the safety of road traffic, the sustainability of road transportation, and the emergence of potentially dangerous situations.

Automated structural design for 3D printed circular composite bridges

<p>The construction industry is in transition. Recyclable materials will become more common to minimise the negative impact of materials. Additive manufacturing with circular composite material is introduced to infrastructure, requiring new design solutions. A thorough understanding of the material behaviour during and after the 3D printing process is needed. It is a misunderstanding that large 3D printing is an upscale of the commonly known small desktop 3D printing. The geometric layout for large print is highly dependent on the window of operation, dominated by the thermal material characteristics. Besides material orthotropy because of fiber orientation, the printed structure is geometrically orthotropic. Different print strategies result in different structural behaviour of the printed part. This paper aims to explain the important factors to consider for the design and engineering of 3D printed load bearing structures, such as bridges, with circular composites, as well as the associated disruption of the value chain.</p>

PENENTUAN LOKASI TOWER CRANE PADA PROYEK KONSTRUKSI BERBASIS SIMULASI

Development of high-level building construction projects that require complex equipment that can be used in high-level construction, equipment used to help complete construction projects called heavy equipment. One of the heavy equipment used in high-rise buildings is a tower crane. The use and layout of tower cranes can speed up the schedule and save on project costs. Therefore many methods have been developed to determine the tower crane layout. This study will discuss determining the location of tower cranes by discussing simulations. The location will be determined based on the site map data which is processed in the form of a geometric arrangement and tower crane data specifications. Location determination is done by comparing the total travel time of several simulated locations according to several different speed criteria in a construction project. Speed criteria are divided into four times the jib speed and trolley speed. Location of the location with the total travel time will be taken as the final result. Different speed criteria will make the total travel time change. ABSTRAKPerkembangan proyek pembangunan gedung bertingkat tinggi yang semakin kompleks menyebabkan diperlukannya peralatan yang dapat mempermudah pembangunan gedung bertingkat, peralatan yang digunakan untuk membantu menyelesaikan tugas konstruksi disebut alat berat. Salah satu peralatan berat yang digunakan pada gedung bertingkat tinggi adalah tower crane. Penggunaan dan tata letak tower crane yang baik dapat mempercepat jadwal dan menghemat biaya proyek. Oleh karena itu banyak dikembangkan metode-metode untuk menentukan tata letak tower crane. Penelitian ini akan membahas penetapan letak lokasi tower crane dengan pendekatan simulasi. Letak lokasi akan ditetapkan berdasarkan data site map yang diolah dalam bentuk geometric layout dan data spesifikasi tower crane. Penetapan lokasi dilakukan dengan cara membandingkan total travel time dari beberapa lokasi yang disimulasi sesuai dengan beberapa kriteria kecepatan yang berbeda-beda pada suatu proyek konstruksi. Kriteria kecepatan terbagi menjadi empat berdasarkan besarnya kecepatan jib dan kecepatan trolley. Letak lokasi dengan total travel time terkecil akan diambil sebagai hasil akhir. Kriteria-kriteria kecepatan yang berbeda disimulasi akan membuat total travel time berubah.