UDO

2021 ◽  
Vol 14 (13) ◽  
pp. 3402-3414
Author(s):  
Junxiong Wang ◽  
Immanuel Trummer ◽  
Debabrota Basu
Keyword(s):  
Reinforcement Learning ◽  
Data Structures ◽  
System Parameter ◽  
Parameter Tuning ◽  
Database Systems ◽  
Database System ◽  
Design Parameters ◽  
Cost Models ◽  
Versatile Tool ◽  
Optimal Configurations

UDO is a versatile tool for offline tuning of database systems for specific workloads. UDO can consider a variety of tuning choices, reaching from picking transaction code variants over index selections up to database system parameter tuning. UDO uses reinforcement learning to converge to near-optimal configurations, creating and evaluating different configurations via actual query executions (instead of relying on simplifying cost models). To cater to different parameter types, UDO distinguishes heavy parameters (which are expensive to change, e.g. physical design parameters) from light parameters. Specifically for optimizing heavy parameters, UDO uses reinforcement learning algorithms that allow delaying the point at which the reward feedback becomes available. This gives us the freedom to optimize the point in time and the order in which different configurations are created and evaluated (by benchmarking a workload sample). UDO uses a cost-based planner to minimize reconfiguration overheads. For instance, it aims to amortize the creation of expensive data structures by consecutively evaluating configurations using them. We evaluate UDO on Postgres as well as MySQL and on TPC-H as well as TPC-C, optimizing a variety of light and heavy parameters concurrently.

Cost-Effective Resource Configurations for Multi-Tenant Database Systems in Public Clouds

2015 ◽  
Vol 5 (2) ◽  
pp. 1-22 ◽  
Author(s):  
Rizwan Mian ◽  
Patrick Martin ◽  
Farhana Zulkernine ◽  
Jose Luis Vazquez-Poletti
Keyword(s):  
Cloud Computing ◽  
Virtual Machines ◽  
Cost Effective ◽  
Database Systems ◽  
Service Level ◽  
Database System ◽  
Resource Provisioning ◽  
Cost Models ◽  
Service Level Agreements ◽  
Expected Cost

Cloud computing is a promising paradigm for deploying applications due to its large resource offerings on a pay-as-you-go basis. This paper examines the problem of determining the most cost-effective provisioning of a multi-tenant database system as a service over public clouds. The authors formulate the problem of resource provisioning, and then define a framework to solve it. Their framework uses heuristic based algorithms to select cost-effective configurations. The algorithms can optionally balance resource costs against penalties incurred from the violation of Service Level Agreements (SLAs) or opt for non SLA violating configurations. The specific resource demands on the virtual machines for a workload and SLAs are accounted for by the performance and cost models, which are used to predict performance and expected cost respectively. The work validates our approach experimentally using workloads based on standard TPC database benchmarks in the Amazon EC2 cloud.

scholarly journals Design of an Ultra-Wideband Microstrip-to-Slotline Transition on Low-Permittivity Substrate

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1329
Author(s):  
Jung Seok Lee ◽  
Gwan Hui Lee ◽  
Wahab Mohyuddin ◽  
Hyun Chul Choi ◽  
Kang Wook Kim
Keyword(s):  
Microstrip Line ◽  
Return Loss ◽  
Analytical Formula ◽  
Parameter Tuning ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Analytical Line ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Low Permittivity

Analysis and design of an ultra-wideband microstrip-to-slotline transition on a low permittivity substrate is presented. Cross-sectional structures along the proposed transition are analyzed using conformal mapping assuming quasi-TEM modes, attaining one analytical line impedance formula with varying design parameters. Although the slotline is a non-TEM transmission line, the transitional structures are configured to have quasi-TEM modes before forming into the slotline. The line impedance is optimally tapered using the Klopfenstein taper, and the electric field shapes are smoothly transformed from microstrip line to slotline. The analytical formula is accurate within 5% difference, and the final transition configuration can be designed without parameter tuning. The implemented microstrip-to-slotline transition possesses insertion loss of less than 1.5 dB per transition and return loss of more than 10 dB from 4.4 to over 40 GHz.

Life Augmentation of Turbine Exhaust System Compensators Through Integrated MADM Optimization Approach of Stress Based Fatigue Cycles

2021 ◽  
Author(s):  
Nitin D. Pagar ◽  
Amit R. Patil
Keyword(s):  
Exhaust System ◽  
Optimization Methods ◽  
Fractional Factorial ◽  
Design Parameters ◽  
Optimization Approach ◽  
Auxiliary Equipment ◽  
Maximum Expansion ◽  
Optimal Configurations ◽  
Selection Of ◽  
Turbine Exhaust

Abstract Exhaust expansion joints, also known as compensators, are found in a variety of applications such as gas turbine exhaust pipes, generators, marine propulsion systems, OEM engines, power units, and auxiliary equipment. The motion compensators employed must have accomplished the maximum expansion-contraction cycle life while imposing the least amount of stress. Discrepancies in the selecting of bellows expansion joint design parameters are corrected by evaluating stress-based fatigue life, which is challenging owing to the complicated form of convolutions. Meridional and circumferential convolution stress equations that influencing fatigue cycles are evaluated and verified with FEA. Fractional factorial Taguchi L25 matrix is used for finding the optimal configurations. The discrete design parameters for the selection of the suitable configuration of the compensators are analysed with the help of the MADM decision making techniques. The multi-response optimization methods GRA, AHP, and TOPSIS are used to determine the parametric selection on a priority basis. It is seen that weighing distribution among the responses plays an important role in these methods and GRA method integrated with principal components shows best optimal configurations. Multiple regression technique applied to these methods also shows that PCA-GRA gives better alternate solutions for the designer unlike the AHP and TOPSIS method. However, higher ranked Taguchi run obtained in these methods may enhance the suitable selection of different design configurations. Obtained PCA-GRG values by Taguchi, Regression and DOE are well matched and verified for the all alternate solutions. Further, it also shows that stress based fatigue cycles obtained in this analysis for the L25 run indicates the range varying from 1.13 × 104 cycles to 9.08 × 105 cycles, which is within 106 cycles. This work will assist the design engineer for selecting the discrete parameters of stiff compensators utilized in power plant thermal appliances.

Constraint Manifold Synthesis of Planar Linkages

1996 ◽  
Author(s):  
A. P. Murray ◽  
J. M. McCarthy
Keyword(s):  
Design Theory ◽  
Geometric Constraints ◽  
Design Parameters ◽  
Design Problems ◽  
Constraint Manifold ◽  
Linkage Design ◽  
Versatile Tool ◽  
Algebraic Constraints ◽  
Planar Linkages

Abstract This paper formulates the design theory of planar four-bar linkages using the planar form of dual quaternions known as planar quaternions. The set of positions reachable by the floating link of a dyad is a quadratic algebraic surface called a constraint manifold. Determining the coefficients of the quadratic form defining this manifold is equivalent to setting the design parameters of the linkage. If the task of the linkage is specified as geometric constraints on the location of the floating link, then algebraic constraints are obtained on the quaternion components. We seek the coefficients of the constraint manifold that satisfies these constraints. The result is an algebraic formulation that is symmetric in its characterization of the linkage and task, and provides a versatile tool for the formulation and solution of linkage design problems.

Integrated and Intelligent Database Systems for Plant Engineering Framework

1994 ◽  
Author(s):  
N. Narikawa ◽  
T. Sato ◽  
N. Sasaki
Keyword(s):  
Three Dimensional ◽  
Database Systems ◽  
Database System ◽  
Structure Design ◽  
Object Oriented Programming ◽  
Design Knowledge ◽  
Automation System ◽  
Functional Requirements ◽  
Plant Structure ◽  
Cad System

Abstract This paper gives an overview of an integrated and intelligent database system for a plant engineering framework. We have integrated existing two-dimensional (2D) CAD systems, a three-dimensional (3D) CAD system, and a relational database system which stores engineering information such as design conditions, maintenance histories, and inherent properties. By integrating these systems, the infrastructure for concurrent engineering has been realized. As for design knowledge, we treat object-oriented programming as a useful knowledge representation method. We analyze the plant structure and functional requirements of the system, and then represented them by using the hierarchical Class structure. Design knowledge accompanies the Class, so we represent it using Method. As a design automation system, we develop an automated design check system. This is implemented by using the Common Lisp Object System. These systems are the main parts of the plant engineering framework, and are utilized in the practical design. We intend to develop a mechanical/electronic design framework using the same approach.

Accessing Data From Multiple Heterogeneous Distributed Database Systems

2019 ◽  
pp. 192-219
Author(s):  
Shefali Trushit Naik
Keyword(s):  
System Parameter ◽  
Database Systems ◽  
Distributed Database ◽  
Sql Server ◽  
Distributed Database Systems ◽  
Data Source ◽  
Database Connectivity ◽  
Relational Database Management ◽  
Complete Process ◽  
Relational Database Management Systems

This chapter describes the method to retrieve data from multiple heterogeneous distributed relational database management systems such as MySQL, PostgreSQL, MS SQL Server, MS Access, etc. into Oracle RDBMS using Oracle's Heterogeneous Gateway Services. The complete process starting from downloading and installation of required software, creation of data source names using open database connectivity, modification of system parameter files, checking connections, creation of synonyms for tables of remote databases into oracle, creation of database links and accessing data from non-oracle databases using database links is explained in great detail. Apart from this, data manipulation in remote databases from Oracle and execution of PL/SQL procedures to manipulate data residing on remote databases is discussed with examples. Troubleshooting common errors during this process is also discussed.

Distributed multi-robot collision avoidance via deep reinforcement learning for navigation in complex scenarios

2020 ◽  
Vol 39 (7) ◽  
pp. 856-892 ◽  
Author(s):  
Tingxiang Fan ◽  
Pinxin Long ◽  
Wenxi Liu ◽  
Jia Pan
Keyword(s):  
Reinforcement Learning ◽  
Collision Avoidance ◽  
Autonomous Navigation ◽  
Large Scale ◽  
Learning Algorithm ◽  
Free Action ◽  
Parameter Tuning ◽  
Movement Velocity ◽  
Robot Systems ◽  
Multi Robot

Developing a safe and efficient collision-avoidance policy for multiple robots is challenging in the decentralized scenarios where each robot generates its paths with limited observation of other robots’ states and intentions. Prior distributed multi-robot collision-avoidance systems often require frequent inter-robot communication or agent-level features to plan a local collision-free action, which is not robust and computationally prohibitive. In addition, the performance of these methods is not comparable with their centralized counterparts in practice. In this article, we present a decentralized sensor-level collision-avoidance policy for multi-robot systems, which shows promising results in practical applications. In particular, our policy directly maps raw sensor measurements to an agent’s steering commands in terms of the movement velocity. As a first step toward reducing the performance gap between decentralized and centralized methods, we present a multi-scenario multi-stage training framework to learn an optimal policy. The policy is trained over a large number of robots in rich, complex environments simultaneously using a policy-gradient-based reinforcement-learning algorithm. The learning algorithm is also integrated into a hybrid control framework to further improve the policy’s robustness and effectiveness. We validate the learned sensor-level collision-3avoidance policy in a variety of simulated and real-world scenarios with thorough performance evaluations for large-scale multi-robot systems. The generalization of the learned policy is verified in a set of unseen scenarios including the navigation of a group of heterogeneous robots and a large-scale scenario with 100 robots. Although the policy is trained using simulation data only, we have successfully deployed it on physical robots with shapes and dynamics characteristics that are different from the simulated agents, in order to demonstrate the controller’s robustness against the simulation-to-real modeling error. Finally, we show that the collision-avoidance policy learned from multi-robot navigation tasks provides an excellent solution for safe and effective autonomous navigation for a single robot working in a dense real human crowd. Our learned policy enables a robot to make effective progress in a crowd without getting stuck. More importantly, the policy has been successfully deployed on different types of physical robot platforms without tedious parameter tuning. Videos are available at https://sites.google.com/view/hybridmrca .

ARTIFICIAL INTELLIGENCE IN DATABASE SECURITY

2004 ◽  
Vol 18 (01) ◽  
pp. 3-17
Author(s):  
YUN BAI ◽  
YAN ZHANG
Keyword(s):  
Artificial Intelligence ◽  
Object Oriented ◽  
Database Systems ◽  
Database System ◽  
Database Security ◽  
Security Policies ◽  
Formal Approach ◽  
Formal Syntax ◽  
Data Objects ◽  
Object Oriented Database

In this paper, we propose a formal approach of Artificial Intelligence (AI) in securing object oriented database systems. We combine the specification of object oriented database with security policies and provide its formal syntax and semantics. The properties in the inheritance of authorizations in object oriented database system and reasoning about authorizations on data objects are also investigated in detail.

Sign in / Sign up

Export Citation Format

Share Document