scholarly journals Budgeted Optimization with Constrained Experiments

2016 ◽  
Vol 56 ◽  
pp. 119-152 ◽  
Author(s):  
Javad Azimi ◽  
Xiaoli Fern ◽  
Alan Fern
Keyword(s):  
Real World ◽  
Unknown Function ◽  
Optimization Problem ◽  
Experimental Results ◽  
Trade Off ◽  
Input Space ◽  
Real World Problem ◽  
Real Functions ◽  
The Cost

Motivated by a real-world problem, we study a novel budgeted optimization problem where the goal is to optimize an unknown function f(.) given a budget by requesting a sequence of samples from the function. In our setting, however, evaluating the function at precisely specified points is not practically possible due to prohibitive costs. Instead, we can only request constrained experiments. A constrained experiment, denoted by Q, specifies a subset of the input space for the experimenter to sample the function from. The outcome of Q includes a sampled experiment x, and its function output f(x). Importantly, as the constraints of Q become looser, the cost of fulfilling the request decreases, but the uncertainty about the location x increases. Our goal is to manage this trade-off by selecting a set of constrained experiments that best optimize f(.) within the budget. We study this problem in two different settings, the non-sequential (or batch) setting where a set of constrained experiments is selected at once, and the sequential setting where experiments are selected one at a time. We evaluate our proposed methods for both settings using synthetic and real functions. The experimental results demonstrate the efficacy of the proposed methods.

scholarly journals Weakly Supervised Disentanglement by Pairwise Similarities

2020 ◽  
Vol 34 (04) ◽  
pp. 3495-3502 ◽  
Author(s):  
Junxiang Chen ◽  
Kayhan Batmanghelich
Keyword(s):  
Real World ◽  
Latent Variables ◽  
Generative Models ◽  
Experimental Results ◽  
New Method ◽  
Weak Supervision ◽  
Real World Problem ◽  
Variational Autoencoder ◽  
Weakly Supervised

Recently, researches related to unsupervised disentanglement learning with deep generative models have gained substantial popularity. However, without introducing supervision, there is no guarantee that the factors of interest can be successfully recovered (Locatello et al. 2018). Motivated by a real-world problem, we propose a setting where the user introduces weak supervision by providing similarities between instances based on a factor to be disentangled. The similarity is provided as either a binary (yes/no) or real-valued label describing whether a pair of instances are similar or not. We propose a new method for weakly supervised disentanglement of latent variables within the framework of Variational Autoencoder. Experimental results demonstrate that utilizing weak supervision improves the performance of the disentanglement method substantially.

A MEMBERSHIP FUNCTION APPROACH FOR COST-RELIABILITY TRADE-OFF OF COTS SELECTION IN FUZZY ENVIRONMENT

2011 ◽  
Vol 18 (06) ◽  
pp. 573-595 ◽  
Author(s):  
PANKAJ GUPTA ◽  
SHILPI VERMA ◽  
MUKESH KUMAR MEHLAWAT
Keyword(s):  
Real World ◽  
Fuzzy Optimization ◽  
Delivery Time ◽  
Minimum Threshold ◽  
Trade Off ◽  
Total Cost ◽  
Fuzzy Environment ◽  
Proposed Model ◽  
The Cost ◽  
Cots Selection

The optimization techniques used in commercial-off-the-shelf (COTS) selection process faces challenges to deal with uncertainty in many important selection parameters, for example, cost, reliability and delivery time. In this paper, we propose a fuzzy optimization model for selecting the best COTS product among the available alternatives for each module in the development of modular software systems. The proposed model minimizes the total cost of the software system satisfying the constraints of minimum threshold on system reliability, maximum threshold on the delivery time of the software, and incompatibility among COTS products. In order to deal with uncertainty in real-world applications of COTS selection, the coefficients of the cost objective function, delivery time constraints and minimum threshold on reliability are considered fuzzy numbers. The fuzzy optimization model is converted into a pair of mathematical programming problems parameterized by possibility (feasibility) level α using Zadeh's extension principle. The solutions of the resultant problems at different α-cuts provide lower and upper bounds of the fuzzy minimum total cost which helps in constructing the membership function of the cost objective function. The solution approach provide fuzzy solutions instead of a single crisp solution thereby giving decision maker enough flexibility in maintaining cost-reliability trade-off of COTS selection besides meeting other important system requirements. A real-world case study is discussed to demonstrate the effectiveness of the proposed model in fuzzy environment.

scholarly journals Adaptively Multi-Objective Adversarial Training for Dialogue Generation

2020 ◽  
Author(s):  
Xuemiao Zhang ◽  
Zhouxing Tan ◽  
Xiaoning Zhang ◽  
Yang Cao ◽  
Rui Yan
Keyword(s):  
Real World ◽  
Optimization Problem ◽  
Experimental Results ◽  
Sampling Distribution ◽  
Multi Objective Optimization ◽  
Generation Task ◽  
Multi Objective ◽  
Adversarial Models ◽  
Adversarial Training ◽  
Real World Datasets

Naive neural dialogue generation models tend to produce repetitive and dull utterances. The promising adversarial models train the generator against a well-designed discriminator to push it to improve towards the expected direction. However, assessing dialogues requires consideration of many aspects of linguistics, which are difficult to be fully covered by a single discriminator. To address it, we reframe the dialogue generation task as a multi-objective optimization problem and propose a novel adversarial dialogue generation framework with multiple discriminators that excel in different objectives for multiple linguistic aspects, called AMPGAN, whose feasibility is proved by theoretical derivations. Moreover, we design an adaptively adjusted sampling distribution to balance the discriminators and promote the overall improvement of the generator by continuing to focus on these objectives that the generator is not performing well relatively. Experimental results on two real-world datasets show a significant improvement over the baselines.

scholarly journals Tight Bounds for Delay-Sensitive Aggregation

2010 ◽  
Vol Vol. 12 no. 1 (Distributed Computing and...) ◽  
Author(s):  
Yvonne Anne Pignolet ◽  
Stefan Schmid ◽  
Roger Wattenhofer
Keyword(s):  
Distributed Computing ◽  
Upper Bound ◽  
Competitive Ratio ◽  
Optimization Problem ◽  
Tree Topology ◽  
Trade Off ◽  
Transmission Cost ◽  
Delay Sensitive ◽  
International Audience ◽  
The Cost

Distributed Computing and Networking International audience This article studies the fundamental trade-off between delay and communication cost in networks. We consider an online optimization problem where nodes are organized in a tree topology. The nodes seek to minimize the time until the root is informed about the changes of their states and to use as few transmissions as possible. We derive an upper bound on the competitive ratio of O(min (h, c)) where h is the tree's height, and c is the transmission cost per edge. Moreover, we prove that this upper bound is tight in the sense that any oblivious algorithm has a ratio of at least Omega(min (h, c)). For chain networks, we prove a tight competitive ratio of Theta(min (root h, c)). Furthermore, we introduce a model for value-sensitive aggregation, where the cost depends on the number of transmissions and the error at the root.

scholarly journals Supply Chain Planning for a Timber Harvesting Plus Sale Tender

2015 ◽  
Vol 63 (1) ◽  
pp. 217-225
Author(s):  
Josef Holoubek ◽  
Martina Lindnerová ◽  
Jitka Janová
Keyword(s):  
Linear Programming ◽  
Supply Chain ◽  
Real World ◽  
Programming Model ◽  
Timber Harvesting ◽  
Selling Price ◽  
Distribution Strategy ◽  
Real World Problem ◽  
The Cost ◽  
Office Software

Since 2010, the Czech State Forest Enterprise has been inviting timber-harvesting tenders while insisting on the forestry company purchasing the timber from the felled trees as well. To win, a tender must offer the greatest difference between the price of the timber purchased and the cost of the operations. Thus, the forest companies are now facing new problem: apart from minimizing the logging costs they are searching for a cross-cutting and mill-distribution strategy that maximizes the selling price of the harvested timber. The optimization model devised by the present paper provides support for finding an optimal timber selling strategy and, as an important contribution, include a detailed plan for cross-cutting the logs and assign them to the particular customers. We keep the support accessible via common office software and the cross-cutting and customer-assigning problem is formulated as a linear programming model for EXCEL, a particular real-world problem is solved and, using expert comparison, the model appears to provide very good results.

scholarly journals A Heuristic Approach for Distributing Pilgrims over Mina Tents

2019 ◽  
Vol 30 (2) ◽  
pp. 11-23
Author(s):  
Mohd K. Shambour Mohd K. Shambour
Keyword(s):  
Real World ◽  
Optimization Problem ◽  
Heuristic Approach ◽  
Experimental Results ◽  
Search Process ◽  
Accommodation Space ◽  
Best Fit ◽  
Holy City ◽  
Available Resources

t. Every year, more than two million Muslims come to the holy city, Makkah, to perform Hajj (the Islamic pilgrimage). One of Hajj rituals is to spend two to three nights in Mina, one of the holy sites. Distributing Muslim pilgrims in Mina, respecting different kinds of constraints, over limited number of tents is a real-world optimization problem. In this paper, a heuristic based algorithm is proposed, called Mina Tent Distribution Algorithm (MTDA), attempting to better utilize the available capacity of Mina’s area in the best possible way with an efficient use of the available resources. MTDA employs seven functions during the search process to find the best fit accommodation for pilgrims on the available tents of Mina. Experimental results revealed that MTDA achieves better performance compared with eight algorithm schemes in all experimental cases. The best result of MTDA was obtained through allocating 80% of the total number of pilgrims over 76.2% of the total available accommodation space of Mina area.

Moving to a New City

2016 ◽  
Vol 22 (5) ◽  
pp. 320
Author(s):  
E. Fanny Sosenke ◽  
Tala Councilman
Keyword(s):  
Real World ◽  
Real World Problem ◽  
New City ◽  
The Cost

A real-world problem about the cost of moving one's household from one city to another.

Developing Schedule With Linear Programming (Case Study: STTF II Project Komplek Sukamukti Banjaran)

2020 ◽  
Vol 4 (02) ◽  
pp. 34-45
Author(s):  
Naufal Dzikri Afifi ◽  
Ika Arum Puspita ◽  
Mohammad Deni Akbar
Keyword(s):  
Linear Programming ◽  
Objective Function ◽  
Project Scheduling ◽  
Time Limit ◽  
Minimum Time ◽  
Service Cost ◽  
Trade Off ◽  
Overtime Work ◽  
The Cost

Shift to The Front II Komplek Sukamukti Banjaran Project is one of the projects implemented by one of the companies engaged in telecommunications. In its implementation, each project including Shift to The Front II Komplek Sukamukti Banjaran has a time limit specified in the contract. Project scheduling is an important role in predicting both the cost and time in a project. Every project should be able to complete the project before or just in the time specified in the contract. Delay in a project can be anticipated by accelerating the duration of completion by using the crashing method with the application of linear programming. Linear programming will help iteration in the calculation of crashing because if linear programming not used, iteration will be repeated. The objective function in this scheduling is to minimize the cost. This study aims to find a trade-off between the costs and the minimum time expected to complete this project. The acceleration of the duration of this study was carried out using the addition of 4 hours of overtime work, 3 hours of overtime work, 2 hours of overtime work, and 1 hour of overtime work. The normal time for this project is 35 days with a service fee of Rp. 52,335,690. From the results of the crashing analysis, the alternative chosen is to add 1 hour of overtime to 34 days with a total service cost of Rp. 52,375,492. This acceleration will affect the entire project because there are 33 different locations worked on Shift to The Front II and if all these locations can be accelerated then the duration of completion of the entire project will be effective

Systems theories

2018 ◽  
Author(s):  
Marc J. Stern
Keyword(s):  
Social Networks ◽  
Problem Solving ◽  
Natural Resources ◽  
Real World ◽  
Common Pool Resources ◽  
Ecological Systems ◽  
Effective Governance ◽  
Social Ecological Systems ◽  
Social Ecological ◽  
Real World Problem

This chapter covers systems theories relevant to understanding and working to enhance the resilience of social-ecological systems. Social-ecological systems contain natural resources, users of those resources, and the interactions between each. The theories in the chapter share lessons about how to build effective governance structures for common pool resources, how to facilitate the spread of worthwhile ideas across social networks, and how to promote collaboration for greater collective impacts than any one organization alone could achieve. Each theory is summarized succinctly and followed by guidance on how to apply it to real world problem solving.

scholarly journals Black Hole Algorithm for Sustainable Design of Counterfort Retaining Walls

2020 ◽  
Vol 12 (7) ◽  
pp. 2767 ◽  
Author(s):  
Víctor Yepes ◽  
José V. Martí ◽  
José García
Keyword(s):  
Black Hole ◽  
Sustainable Design ◽  
Retaining Walls ◽  
The Other ◽  
Trade Off ◽  
Construction Company ◽  
Geometric Variables ◽  
The Stability ◽  
The Cost ◽  
Black Hole Algorithm

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.

Sign in / Sign up

Export Citation Format

Share Document