159 research outputs found
Virtualni i empirijski uvod u modernizaciju zemljišne evidencije
The land record modernisation is vital for nations under developing economy. The modernisation of land records is tedious process. The written part of the cadastre is modified with ease by use of computers. The map portion of the cadastre is critical for modernisation. The land record modernisation with two procedures and their associated enigma is analysed in this paper. The predominant source of error while performing overlay analysis with digitised land records on satellite images is land slope and the limiting land slope of 8° 15\u27 00\u27\u27 is recommended through virtual analysis. The empirical analysis identified the land area suitable for total station or chain survey. The land area less than 900 m2 requires chain survey and land area greater than 900 m2 requires total station survey. The crucial part of land record modernisation is to identify errors and error sources to create reliable land record to cater needs of land under current development zone. The land under future development zone needs to be segregated to identify suitable area for total station or chain surveying.Modernizacija zemljišne evidencije važna je za nacije s gospodarstvom u razvoju. Modernizacija zemljišne evidencije težak je proces. Pisani dio katastra lako se modificira uz pomoć računala. Grafički dio katastra kritičan je u pogledu modernizacije. U ovom radu analizirana je modernizacija zemljišne evidencije kroz dva postupka i s njima povezanu enigmu. Prevladavajući izvor pogrešaka prilikom analize preklapanja s digitaliziranim zemljišnim podacima na satelitskim snimkama je nagib zemljišta te se preporuča ograničavajući nagib zemljišta od 8° 15\u27 00\u27\u27 kroz virtualnu analizu. Empirijskom analizom utvrđuje se površina zemljišta primjerena za izmjeru geodetskom mjernom stanicom ili lancem. Površina zemljišta manja od 900 m2 zahtijeva izmjeru lancem, a površina zemljišta veća od 900 m2 zahtijeva izmjeru geodetskom mjernom stanicom. Ključni dio modernizacije zemljišne evidencije odnosi se na utvrđivanje pogrešaka i izvora pogrešaka kako bi se izradila pouzdana evidencija zemljišta u svrhu zadovoljavanja potreba zemljišta u trenutnoj zoni razvoja. Zemljište u budućoj zoni razvoja treba biti izdvojeno kako bi se utvrdile odgovarajuće površine za izmjeru geodetskom mjernom stanicom ili lancem
Fusing Long Short-Term Memory and Autoencoder Models for Robust Anomaly Detection in Indoor Air Quality Time-Series Data
People spend most of their time indoors by choice or by need. Carbon dioxide (CO2) accumulation can cause various adverse health effects, including vertigo, headache, and fatigue. Therefore, monitoring indoor air quality(IAQ) is necessary for various health reasons. The market is flooded with air quality monitoring devices. However, the ordinary public does not make use of them because they are expensive and difficult to obtain. Several research studies have been carried out to monitor indoor air quality with the help of the Internet of Things(IoT), which has greatly simplified the method for monitoring IAQ. In this research, we offer an improved IoT based IAQ monitoring system with AI-powered recommendations. Our suggested system relies on the Message Queuing Telemetry Transport(MQTT) protocol for communication between IoT devices. In addition, the gathered CO2 occupancy data is used together with the deep learning approach of Long Short-Term Memory and Autoencoder (LSTM-AE) to detect anomalies or outliers in CO2 concentrations. Due to a close connection between air quality and human health and well-being, the detection of anomalies in the data of IAQ has emerged as an essential topic of study. Anomalies requiring the observation of correlations spanning numerous data points (i.e., often referred to as long-term dependencies) were not detectable by conventional statistical and basic machine learning (ML) related techniques in the sector of IAQ. Hence this research uses the LSTM-AE model to address this issue. In comparison to previous similar models, our experimental results on a generated CO2 occupancy time series reveal a robust and powerful accuracy of 99.49%
Portfolio Optimization and the Random Magnet Problem
Diversification of an investment into independently fluctuating assets
reduces its risk. In reality, movement of assets are are mutually correlated
and therefore knowledge of cross--correlations among asset price movements are
of great importance. Our results support the possibility that the problem of
finding an investment in stocks which exposes invested funds to a minimum level
of risk is analogous to the problem of finding the magnetization of a random
magnet. The interactions for this ``random magnet problem'' are given by the
cross-correlation matrix {\bf \sf C} of stock returns. We find that random
matrix theory allows us to make an estimate for {\bf \sf C} which outperforms
the standard estimate in terms of constructing an investment which carries a
minimum level of risk.Comment: 12 pages, 4 figures, revte
Alternation of different fluctuation regimes in the stock market dynamics
Based on the tick-by-tick stock prices from the German and American stock
markets, we study the statistical properties of the distribution of the
individual stocks and the index returns in highly collective and noisy
intervals of trading, separately. We show that periods characterized by the
strong inter-stock couplings can be associated with the distributions of index
fluctuations which reveal more pronounced tails than in the case of weaker
couplings in the market. During periods of strong correlations in the German
market these distributions can even reveal an apparent L\'evy-stable component.Comment: 19 page
The Apparent Madness of Crowds: Irrational collective behavior emerging from interactions among rational agents
Standard economic theory assumes that agents in markets behave rationally.
However, the observation of extremely large fluctuations in the price of
financial assets that are not correlated to changes in their fundamental value,
as well as the extreme instance of financial bubbles and crashes, imply that
markets (at least occasionally) do display irrational behavior. In this paper,
we briefly outline our recent work demonstrating that a market with interacting
agents having bounded rationality can display price fluctuations that are {\em
quantitatively} similar to those seen in real markets.Comment: 4 pages, 1 figure, to appear in Proceedings of International Workshop
on "Econophysics of Stock Markets and Minority Games" (Econophys-Kolkata II),
Feb 14-17, 200
Bioactive potential of actinobacteria isolated from the gut of marine fishes
1280-1285The study was undertaken to explore the gut-associated actinobacteria from two marine fish with special reference to antimicrobial and anti-quorum sensing activity. A total of 40 actinobacterial strains were isolated from fish gut samples using starch casein agar and Kuster’s agar medium. About 14 morphologically different strains recovered from Rastrelliger kanagurta (Indian mackerel) and Panna microdon (Panna croaker) were screened for the antimicrobial activity against Staphylococcus aureus MTCC96, Escherichia coli MTCC739, Salmonella enterica, Candida albicans, and quorum sensing inhibition (QSI) against Chromobacterium violaceum and Serratia marcescens. The actinobacterial strain IM20 from R. kanagurta showed both antimicrobial and QSI activity, whereas the strains PCA1 and PCA4 from P. microdon showed only antimicrobial activity. Strain IM20, which showed wide range of activity, was selected as the potential strain for further studies. Thus, the findings suggested that the fish-associated actinobacteria is a promising source for antimicrobial compounds for developing novel therapeutic drugs
Long-Time Fluctuations in a Dynamical Model of Stock Market Indices
Financial time series typically exhibit strong fluctuations that cannot be
described by a Gaussian distribution. In recent empirical studies of stock
market indices it was examined whether the distribution P(r) of returns r(tau)
after some time tau can be described by a (truncated) Levy-stable distribution
L_{alpha}(r) with some index 0 < alpha <= 2. While the Levy distribution cannot
be expressed in a closed form, one can identify its parameters by testing the
dependence of the central peak height on tau as well as the power-law decay of
the tails. In an earlier study [Mantegna and Stanley, Nature 376, 46 (1995)] it
was found that the behavior of the central peak of P(r) for the Standard & Poor
500 index is consistent with the Levy distribution with alpha=1.4. In a more
recent study [Gopikrishnan et al., Phys. Rev. E 60, 5305 (1999)] it was found
that the tails of P(r) exhibit a power-law decay with an exponent alpha ~= 3,
thus deviating from the Levy distribution. In this paper we study the
distribution of returns in a generic model that describes the dynamics of stock
market indices. For the distributions P(r) generated by this model, we observe
that the scaling of the central peak is consistent with a Levy distribution
while the tails exhibit a power-law distribution with an exponent alpha > 2,
namely beyond the range of Levy-stable distributions. Our results are in
agreement with both empirical studies and reconcile the apparent disagreement
between their results
Scaling of the distribution of price fluctuations of individual companies
We present a phenomenological study of stock price fluctuations of individual
companies. We systematically analyze two different databases covering
securities from the three major US stock markets: (a) the New York Stock
Exchange, (b) the American Stock Exchange, and (c) the National Association of
Securities Dealers Automated Quotation stock market. Specifically, we consider
(i) the trades and quotes database, for which we analyze 40 million records for
1000 US companies for the 2-year period 1994--95, and (ii) the Center for
Research and Security Prices database, for which we analyze 35 million daily
records for approximately 16,000 companies in the 35-year period 1962--96. We
study the probability distribution of returns over varying time scales , where varies by a factor of ---from 5 min up to
4 years. For time scales from 5~min up to approximately 16~days, we
find that the tails of the distributions can be well described by a power-law
decay, characterized by an exponent ---well outside the
stable L\'evy regime . For time scales days, we observe results consistent with a slow
convergence to Gaussian behavior. We also analyze the role of cross
correlations between the returns of different companies and relate these
correlations to the distribution of returns for market indices.Comment: 10pages 2 column format with 11 eps figures. LaTeX file requiring
epsf, multicol,revtex. Submitted to PR
Economic Fluctuations and Diffusion
Stock price changes occur through transactions, just as diffusion in physical
systems occurs through molecular collisions. We systematically explore this
analogy and quantify the relation between trading activity - measured by the
number of transactions - and the price change ,
for a given stock, over a time interval . To this end, we
analyze a database documenting every transaction for 1000 US stocks over the
two-year period 1994-1995. We find that price movements are equivalent to a
complex variant of diffusion, where the diffusion coefficient fluctuates
drastically in time. We relate the analog of the diffusion coefficient to two
microscopic quantities: (i) the number of transactions in
, which is the analog of the number of collisions and (ii) the local
variance of the price changes for all transactions in , which is the analog of the local mean square displacement between
collisions. We study the distributions of both and , and find that they display power-law tails. Further, we find that
displays long-range power-law correlations in time, whereas
does not. Our results are consistent with the interpretation
that the pronounced tails of the distribution of w_{\Delta t}|
G_{\Delta t} |N_{\Delta t}$.Comment: RevTex 2 column format. 6 pages, 36 references, 15 eps figure
Components of multifractality in high-frequency stock returns
We analyzed multifractal properties of 5-minute stock returns from a period
of over two years for 100 highly capitalized American companies. The two
sources: fat-tailed probability distributions and nonlinear temporal
correlations, vitally contribute to the observed multifractal dynamics of the
returns. For majority of the companies the temporal correlations constitute a
much more significant related factor, however.Comment: to appear in Physica
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