Some applications of probability theory in statistical mechanics

Imperial Users onl

Estimation of Apartment Submarkets

The analysis of apartment sub-markets and the modelling of such markets have attracted a considerable degree of attention recently. This study compares apartment submarkets within a major European city. The price behaviour of the Dublin, Ireland apartment market is tested using hedonic models and aggregate and disaggregate data. The results strongly indicate that the modelling of apartment markets at the disaggregate level does result in significant improvements in estimation in comparison to estimations undertaken at an aggregate level. This particular apartment market is especially interesting, due to the introduction of fiscal incentives in inner-city locations. In order to fully understand the Dublin apartment market requires an appreciation of the role played by tax breaks for owner-occupiers and investors in urban renewal locations. The results show that different submarkets responded differently. The central city apartment market [urban renewal locations] saw a short-term stabilization of prices in the months following the fiscal changes, with price increases accelerating again shortly afterwards.

Low-Cost QCM Sensor System for Screening Semen Samples

Artificial insemination is a well-established part of modern agricultural practice. A viable semen sample is judged by the total number of spermatozoa (sperm) in the sample and the motility of the sperm. In this paper, we report the development of a reusable measurement cell and electronics for screening semen samples based on the Quartz Crystal Microbalance (QCM) and Universal Frequency to Digital Converter (UFDC-1) to produce a low-cost sensor system. After introducing the semen sample at one end of the measurement cell, sperm swim down a channel before causing a frequency change on the QCM. Data is presented that shows the different frequency changes using a commercial frequency counter caused by porcine semen samples, one two days old and one twenty one days old. Similar data is presented for a motile semen sample measurement using the low-cost UFDC-1

Low-Cost QCM Sensor System for Screening Semen Samples

Artificial insemination is a well-established part of modern agricultural practice. A viable semen sample is judged by the total number of spermatozoa (sperm) in the sample and the motility of the sperm. In this paper, we report the development of a reusable measurement cell and electronics for screening semen samples based on the Quartz Crystal Microbalance (QCM) and Universal Frequency to Digital Converter (UFDC-1) to produce a low-cost sensor system. After introducing the semen sample at one end of the measurement cell, sperm swim down a channel before causing a frequency change on the QCM. Data is presented that shows the different frequency changes using a commercial frequency counter caused by porcine semen samples, one two days old and one twenty one days old. Similar data is presented for a motile semen sample measurement using the low-cost UFDC-1

Rapid and robust spin state amplification

Electron and nuclear spins have been employed in many of the early demonstrations of quantum technology (QT). However applications in real world QT are limited by the difficulty of measuring single spins. Here we show that it is possible to rapidly and robustly amplify a spin state using a lattice of ancillary spins. The model we employ corresponds to an extremely simple experimental system: a homogenous Ising-coupled spin lattice in one, two or three dimensions, driven by a continuous microwave field. We establish that the process can operate at finite temperature (imperfect initial polarisation) and under the effects of various forms of decoherence.Comment: 5 pages, 2 figure

Bankruptcy risk model and empirical tests

We analyze the size dependence and temporal stability of firm bankruptcy risk in the US economy by applying Zipf scaling techniques. We focus on a single risk factor-the debt-to-asset ratio R-in order to study the stability of the Zipf distribution of R over time. We find that the Zipf exponent increases during market crashes, implying that firms go bankrupt with larger values of R. Based on the Zipf analysis, we employ Bayes's theorem and relate the conditional probability that a bankrupt firm has a ratio R with the conditional probability of bankruptcy for a firm with a given R value. For 2,737 bankrupt firms, we demonstrate size dependence in assets change during the bankruptcy proceedings. Prepetition firm assets and petition firm assets follow Zipf distributions but with different exponents, meaning that firms with smaller assets adjust their assets more than firms with larger assets during the bankruptcy process. We compare bankrupt firms with nonbankrupt firms by analyzing the assets and liabilities of two large subsets of the US economy: 2,545 Nasdaq members and 1,680 New York Stock Exchange (NYSE) members. We find that both assets and liabilities follow a Pareto distribution. The finding is not a trivial consequence of the Zipf scaling relationship of firm size quantified by employees-although the market capitalization of Nasdaq stocks follows a Pareto distribution, the same distribution does not describe NYSE stocks. We propose a coupled Simon model that simultaneously evolves both assets and debt with the possibility of bankruptcy, and we also consider the possibility of firm mergers.Comment: 8 pages, 8 figure

Pengembangan Model Evaluasi Total Cost of Ownership untuk Mengestimasi Umur Ekonomis pada Sebuah Subsistem Produksi yang Terdiri dari Beberapa Komponen (Studi Kasus di Industri Semen)

Dalam ekonomi global, khususnya untuk item dengan nilai yang besar, pertimbangan biaya tidak berhenti hanya pada akuisisi melainkan sepanjang siklus hidup. Total Cost of Ownerhip (TCO) merupakan penjumlahan dari seluruh biaya dalam produk selama siklus hidup. Penggunaan istilah TCO dibandingkan life cycle cost (LCC) dipilih karena penelitian terfokus pada kepemilikan aset fisik. TCO dapat digunakan sebagai alat untuk membantu dalam pembuatan keputusan penggantian aset melalui penentuan umur ekonomis yang dihitung melalui equivalent uniform annualized cost (EUAC) TCO dengan mempertimbangkan discount rate dan tingkat inflasi per tahun. TCO melalui EUAC diproyeksikan ke dalam jangka waktu tertentu hingga mendapatkan nilai minimum untuk menentukan umur ekonomis. Umur ekonomis pada penelitian ini dipertimbangkan dalam ruang lingkup sistem untuk menemukan jangka waktu pengoperasian sistem yang dapat meminimalkan biaya dan menemukan komponen kritis yang berdampak pada EUAC dan umur ekonomis sistem tersebut. Pada penelitian ini, model TCO akan dikembangkan pada subsistem produksi yaitu Raw Mill dan Packer dengan mengakomodasi faktor ketidakpastian yang berkaitan dengan operasional, pemeliharaan, dan faktor produksi yang digunakan untuk mengestimasi umur ekonomis. Tujuan penelitian ini antara lain adalah melakukan evaluasi atau analisis terkait struktur TCO dan komponen penyusun dari TCO, mengembangkan teknik solusi dan rekayasa matematis yang diperlukan untuk mendapatkan profil TCO yang dapat digunakan untuk mengevaluasi TCO, dan menentukan estimasi umur ekonomis sistem, EUAC, profil biaya komponen, dan komponen kritis pada sistem Raw Mill dan Packer. Pengembangan model TCO dilakukan dengan metode simulasi monte carlo. Hasil estimasi umur ekonomis untuk sistem Raw Mill adalah 15 tahun dan Packer adalah 28 tahun. Nilai umur ekonomis dan EUAC pada sistem Raw Mill dipengaruhi secara signifikan oleh Roller Mill dari aspek kerusakan dan Raw Mill Fan dari aspek operasional, sedangkan untuk Packer dipengaruhi oleh Packing Machine secara keseluruhan

Layer guided-acoustic plate mode biosensors for monitoring MHC-peptide interactions

The transduction signals from the immobilisation of a class I heavy chain, HLA-A2, on a layer guided acoustic plate mode device, followed by binding of beta(2)-microglobulin and subsequent selective binding of a target peptide are reported