Size versus truthfulness in the house allocation problem

We study the House Allocation problem (also known as the Assignment problem), i.e., the problem of allocating a set of objects among a set of agents, where each agent has ordinal preferences (possibly involving ties) over a subset of the objects. We focus on truthful mechanisms without monetary transfers for finding large Pareto optimal matchings. It is straightforward to show that no deterministic truthful mechanism can approximate a maximum cardinality Pareto optimal matching with ratio better than 2. We thus consider randomized mechanisms. We give a natural and explicit extension of the classical Random Serial Dictatorship Mechanism (RSDM) specifically for the House Allocation problem where preference lists can include ties. We thus obtain a universally truthful randomized mechanism for finding a Pareto optimal matching and show that it achieves an approximation ratio of eovere-1. The same bound holds even when agents have priorities (weights) and our goal is to find a maximum weight (as opposed to maximum cardinality) Pareto optimal matching. On the other hand we give a lower bound of 18 over 13 on the approximation ratio of any universally truthful Pareto optimal mechanism in settings with strict preferences. In the case that the mechanism must additionally be non-bossy, an improved lower bound of eovere-1 holds. This lower bound is tight given that RSDM for strict preference lists is non-bossy. We moreover interpret our problem in terms of the classical secretary problem and prove that our mechanism provides the best randomized strategy of the administrator who interviews the applicants

Dynamic Optimization of Autocatalytic Esterification in Semi Batch Reactor using Orthogonal Collocation and Control Vector Parameterization Method

Catalyzed Esterification of Propionic Anhydride with 2-Butanol is commonly applied in semi batch reactors where the process variables undergo significant changes during the duration of the batch. In this semi batch operation, there is no steady state and thus no constant setpoints around which the key variables can be regulated

Pengaruh Ethical Ideology Terhadap Ethical Judgements Pada Mahasiswa Akuntansi

Ethical judgement is the process by which an individual determines that one of the alternatives is morally right and the other alternative is morally wrong. This capability is very important and needed by each individual in performing their duties. This study aims to analyze the effect of ethical ideology towards ethical judgments, ethical ideology consist of idealism and relativism. This study was conducted in 2015. The data was collected using a questionnaire. The population of this study were students Accounting Profession in Semarang city and the sample using simple random sampling technique. The analysis technique used is multiple linear regression and the Kruskal-Wallis test. Statistical analysis showed that idealism and relativism has significant effect on ethical judgments. The results indicate that the ethical ideology have a significant effect on ethical judgments, where idealism has a positive significant and relativism has a negative significant. And it is known that the group absolutist judge stricter than the other groups

Normal soaking extraction (NSE) of rotenone from Derris elliptica

Derris elliptica or the tuba plant contains rotenone, bio-active compound known that has the potential to be used as bio-pesticide. Bio-pesticide is the best-known alternative bio-pesticide which has the potential to replace the use of conventional pesticides, as it is more environmentally friendly. The main objective of the paper is to obtain the best extraction solvent for optimizing the yield in rotenone extraction. Rotenone was extracted from Derris root using three different parts of roots and three types of solvent in Normal Soaking Extraction (NSE). The types of Derris roots are: (1) Fine root (2) Coarse root (3) Stem. The three types of solvent system are: (1) Acetone 95 % (v/v), (2) Chloroform 99.9 % (v/v) and (3) a mixture of ethanol: H2O (9:1) added with oxalic acid (1mg/ml). The liquid crude extracts were further cleaned up to remove the fine debris of roots. The presence of rotenone was confirmed using qualitative analysis Thin Layer Chromatography (TLC) and thereupon the determination of rotenone content was carried out using High Performance Liquid Chromatography (HPLC). From the results obtained, it was found that the Normal Soaking Extraction (NSE) using acetone 95 % (v/v) was the best method to extract the highest yield of rotenone; 1.14 % (w/w)

Optimasi Pupuk Dalam Usahatani LEISA Bawang Merah Di Dataran Rendah

Usahatani bawang merah telah dianggap menggunakan input bahan kimia sintetik terlalu tinggi, sehingga perlu dicari teknologi alternatif yang lebih ramah lingkungan dengan mengganti sebagian input kimia sintetik dengan bahan alami, seperti bahan organik. Untuk itu, diadakan kegiatan penelitian di Desa Kemukten, Kecamatan Kersana dari bulan Juni sampai dengan September 2003 menggunakan bawang merah varietas bangkok warso yang ditanam dengan jarak 17x17 cm. Tujuan penelitian ini adalah untuk mendapatkan macam pupuk organik dan dosis pupuk NPK untuk meningkatkan hasil sayuran dalam USAhatani Leisa di dataran rendah. Rancangan percobaan menggunakan acak kelompok dengan tiga ulangan. Perlakuannya adalah kombinasi jenis pupuk organik (Oo = tanpa pupuk organik, O1= kompos ampas tebu dan O2 = bokasi jerami) dengan dosis pupuk NPK (Po = 0 kg/ha; P1 = 375 kg/ha; P2 = 750 kg/ha; P3 = 1.125 kg/ha, dan P4 = 1.500 kg/ha). Hasil percobaan menunjukkan bahwa pada tanaman yang tidak diberi bahan organik, penggunaan pupuk NPK (15-15-15) kadar 375 kg/ha sudah meningkatkan bobot basah dan bobot kering bawang merah secara nyata. Pada tanaman yang diberi bahan organik ampas tebu, pemupukan NPK (15-15-15) dosis 375 kg/ha sudah memberikan kenaikan hasil bawang merah baik bobot basah maupun bobot kering secara nyata. Sedang penggunaan bahan organik bokasi jerami dengan pupuk NPK (15-15-15) dosis 375 kg/ha hanya meningkatkan bobot basah hasil bawang merah secara nyata.Optimization of vegetable production input in lowland under LEISA system. Production of shallot has been considered to use high chemical synthetic input, so there is a need to look for an alternative technology which is more environmentally safe by replacing some chemicals input with natural product such as organic matters. The experiment has been conducted in Kemukten, Kersana, Brebes from June up to September 2003 by using shallot variety bangkok warso that was planted at planting distance of 17x17 cm. The objective of this experiment was to find out kind of organic manure and dosage of NPK to increase yield of shallot under LEI SA system. The experimental arranged in a randomized complete block design with three replications. The treatments were the combination between kind of organic matters without organic matter, sugarcane waste, and fermented rice straw) with dosages of NPK (0 kg/ha; 375 kg/ha; 750 kg/ha; 1,125 kg/ha; and 1,500 kg/ha). The results showed that shallot plantation without organic matters combined with 375 kg/ha NPK (15-15-15) could improve fresh and dry crops weight significantly. The application of sugarcane waste in combination with 375 kg/ha NPK (15-15-15), significantly increased fresh and dry weight of the harvested crops, while application of fermented rice straw organic matters in combination with 375 kg/ha NPK (15-15-15) just improved the yield in term of fresh crops weight significantly

Assessing human error during collecting a hydrocarbon sample of the chemical plant using therp

This paper reports the assessment method of the hydrocarbon sample collection standard operation procedure (SOP) using THERP. The Performance Shaping Factors (PSF) from THERP analyzed and assessed the human errors during collecting a hydrocarbon sample of a petrochemical refinery plant. Twenty-two scenarios and standard operating procedures (SOP) are analysed to identify the human errors. The event tree analysis is employed to quantify the human error. The finding revealed that the THERP is a feasible technique for measuring human performance errors and performance shaping factors.Keywords: THERP, Event Tree Analysis, Human Error Probability, Hydrocarbon SampleCollection SOP

Kinematic Self-Similar Plane Symmetric Solutions

This paper is devoted to classify the most general plane symmetric spacetimes according to kinematic self-similar perfect fluid and dust solutions. We provide a classification of the kinematic self-similarity of the first, second, zeroth and infinite kinds with different equations of state, where the self-similar vector is not only tilted but also orthogonal and parallel to the fluid flow. This scheme of classification yields twenty four plane symmetric kinematic self-similar solutions. Some of these solutions turn out to be vacuum. These solutions can be matched with the already classified plane symmetric solutions under particular coordinate transformations. As a result, these reduce to sixteen independent plane symmetric kinematic self-similar solutions.Comment: 29 pages, accepted for publication in Classical Quantum Gravit