Space Filling Research Articles

Controls of depositional facies patterns on a modern carbonate platform: Insight from hydrodynamic modeling

AbstractRecent studies of Holocene deposits on Great Bahama Bank (GBB) have focused on mapping of sediment distribution, an analysis of the variable filling of accommodation space, a comparison between ooid sandbodies and an examination of whitings and mud production. Collectively, these studies provide insight into the variability in depositional facies that challenge outcrop and subsurface interpretations. Missing from these analyses, however, has been a scrutiny of the physical controls over deposition. To partially explore these controls, a hydrodynamic model forced by prevailing ocean hydrodynamics, tides, winds and atmospheric pressure was developed. Current intensity and direction can be examined at short time steps over 1 year, and GBB can be partitioned into zones of mean annual hydrodynamic energy. Areas of vigorous tidal exchange correspond to localities where platform margin ooid sand shoals have developed. There is a predictive relationship between increasing peak current velocity and increasing area of the sandbody for the Cat, Joulter and Schooners Cays and Tongue of the Ocean sites. A connection between platform‐top hydrodynamics and the formation/suppression of whitings is evidenced west of Andros, suggesting a relationship between the production/deposition of platform‐top muds and off‐platform circulation. Filling of accommodation space can be partially related to platform topography and hydrodynamic flow. For instance, accommodation filling occurs locally along the platform margin by grainstones in areas of high tidal exchange as well as by mud accumulation leeward of islands. Conversely, the development of hiatal surfaces (sites of non‐deposition) occurs in areas not sheltered by islands, such as the southern GBB, where platform‐top currents are persistently vigorous. A broader understanding of platform‐top currents and their diverse controls can aid interpretation of the rock record, including the type and distribution of platform‐top sediments, the distribution of hiatal surfaces and, therefore, identification of locations which have the potential to host more complete depositional cycles.

New Essentials of Economic Theory III. Economic Applications

This paper presents applications of our theory to description of particular economic problems. We give all definitions and equations in Part I and II of our work. Here we argue propagation of small perturbations of economic variables and transactions on economic space. We show that small perturbations may follow wave equations that have parallels to propagation of sound waves and surface waves in fluids. We underline that nature of economic waves is completely different from waves in physical fluids but parallels between them may be useful for their studies. Wave generation, propagation and interactions are the most general properties of any complex system. Descriptions of economic waves on economic space fill existing gap in economic modeling. Usage of economic space allows distribute agents by their risk ratings as coordinates. Agents on economic space cover economic domain bounded by minimum and maximum risk grades. Change of risk ratings of agents due to their economic activity, economic processes or other factors induce flows of economic variables, transactions and expectations. Borders of economic domain cause fluctuations of economic flows and mean risks and these fluctuations describe business cycles. For example fluctuations of credit flows model credit cycles, investment flows model investment cycles and etc. Further we model assets price disturbances as consequences of relations between transactions and expectations. As last economic sample we argue classical Black-Scholes-Merton option pricing model and discuss problems those arise from modeling on economic space.

Chain organization of human interphase chromosome determines the spatiotemporal dynamics of chromatin loci.

We investigate spatiotemporal dynamics of human interphase chromosomes by employing a heteropolymer model that incorporates the information of human chromosomes inferred from Hi-C data. Despite considerable heterogeneities in the chromosome structures generated from our model, chromatins are organized into crumpled globules with space-filling (SF) statistics characterized by a single universal scaling exponent (ν = 1/3), and this exponent alone can offer a quantitative account of experimentally observed, many different features of chromosome dynamics. The local chromosome structures, whose scale corresponds to that of topologically associated domains (∼ 0.1 − 1 Mb), display dynamics with a fast relaxation time (≲ 1 − 10 sec); in contrast, the long-range spatial reorganization of the entire chromatin ( Mb) occurs on a much slower time scale (≳ hour), providing the dynamic basis of cell-to-cell variability and glass-like behavior of chromosomes. Biological activities, modeled using stronger isotropic white noises added to active loci, accelerate the relaxation dynamics of chromatin domains associated with the low frequency modes and induce phase segregation between the active and inactive loci. Surprisingly, however, they do not significantly change the dynamics at local scales from those obtained under passive conditions. Our study underscores the role of chain organization of chromosome in determining the spatiotemporal dynamics of chromatin loci.

The Discovery of the Romero VMS Deposit and Its Bearing on the Metallogenic Evolution of Hispaniola during the Cretaceous

The recently discovered Romero deposit, located in the Tres Palmas district, Cordillera Central of the Dominican Republic, has probable reserves of 840,000 oz gold, 980,000 oz silver and 136 Mlb copper. Mineralization is hosted by intermediate volcanic and volcaniclastic rocks of the lower stratigraphic sequence of the Cretaceous Tireo formation. The andesitic host rocks yield a U-Pb zircon concordia age of 116 ± 10 Ma. Au–Ag–Cu(–Zn) mineralization is divided into: (1) an upper domain with stacked massive sulfide lenses and sulfide dissemination within a 20-m-thick level of massive anhydrite-gypsum nodules, and (2) a lower domain with a high-grade stockwork mineralization in the form of cm-scale veins with open space fillings of fibrous silica and chalcopyrite, sphalerite, pyrite (+electrum ± Au–Ag tellurides). The δ34S values of sulfides from the upper (−7.6 and +0.9‰) and lower (−2.4 and +5.6‰) domains are consistent with a heterogeneous sourcing of S, probably combining inorganically and organically induced reduction of Albian-Aptian seawater sulfate. Despite this, a magmatic source for sulfur cannot be discarded. The δ34S (+19.2 and +20.0‰) and δ18O (+12.5 and +14.2‰) values of anhydrite-gypsum nodules are also consistent with a seawater sulfate source and suggest crystallization in equilibrium with aqueous sulfides at temperatures higher than 250 °C. These data point to a classification of Romero as a volcanogenic massive sulfide (VMS) deposit formed in an axial position of the Greater Antilles paleo-arc in connection with island arc tholeiitic magmatism during a steady-state subduction regime. Circulation of hydrothermal fluids could have been promoted by a local extensional tectonic regime expressed in the Tres Palmas district as a graben structure.

Archipiélagos narrativos y culturales

La relevancia del espacio en las colecciones de relatos integrados, modalidad narrativa ubicada entre el libro de cuentos misceláneos y la novela, es perceptible tanto en lo temático como en lo formal (Sánchez Carbó, 2012), ya que por sus implicaciones en la estructura se vincula a la llamada literatura espacial (Frank, 1991). Como elemento explícito de integración de los relatos de una colección, el espacio representado puede interpretarse como una toma de posición identitaria, es decir, como una intersección en la que convergen aspectos biográficos e intereses estéticos, sociales, culturales o políticos de los autores. En la literatura hispanoamericana es un elemento de integración frecuente en muchas colecciones, lo que permite, en primer lugar, elaborar una cartografía literaria (Tally, 2012) compuesta por cinco zonas (“Lugares imaginarios”, “Espacios cerrados e interiores”, “Provincias”, “Países y capitales” y “Fronteras y Exilios”) y, en segundo, proponer al archipiélago como un modelo de espacialidad propicio para evidenciar, por una parte, las tensiones y las relaciones entre las partes, y, por otra, para visibilizar la diversidad cultural hispanoamericana desde la literatura.

Archimedean Tiling Patterns Self-Assembled from X-Shaped Rod–Coil Copolymers with Hydrogen Bonds

On the basis of self-consistent field theory (SCFT), we demonstrate that X-shaped rod–coil molecules with hydrogen-bonding groups self-assemble into Archimedean tiling patterns including [36], [44], [63], [3.4.6.4], and [(3.6)2], and dual tiling patterns including dual-[32.4.3.4]. The rod blocks form the edges of polygons, coil blocks fill in the inner spaces of polygons, and the existence of hydrogen bonds further decreases the domain size. A new mechanism is proposed to guide the formation of Archimedean tiling patterns: the fabrication of tiling patterns is controlled by the relationship between the length–diameter ratio β and volume fraction fR of rigid cores in X-shaped supra-macromolecules. This study provides a concept of macromolecular tiling for producing Archimedean tilings and suggests X-shaped rod–coil supra-macromolecules with hydrogen-bonding groups as an ideal platform for the fabrication of two-dimensional nanoscale patterns.

CLUSTERING AND INDEXING HISTORIC VESSEL MOVEMENT DATA WITH SPACE FILLING CURVES

Abstract. This paper reports on the result of an on-going study using Space Filling Curves (SFCs) for indexing and clustering vessel movement message data (obtained via the Automated Identification System, AIS) inside a geographical Database Management System (Geo-DBMS). With AIS, vessels transmit their positions in intervals ranging from 2 seconds to 3 minutes. Every 6 minutes voyage related information is broadcast. Relevant AIS messages contain a position, timestamp and vessel identifier. This information can be stored in a DBMS as separate columns with different types (as 2D point plus time plus identifier), or in an integrated column (as higher dimensional 4D point which is encoded as the position on a space filling curve, that we will call the SFC-key). Subsequently, indexing based on this SFC-key column can replace separate indexes (where this one integrated index will need less storage space than separate indexes). Moreover, this integrated index allows a good clustering (physical ordering of the table). Also, in an approach with separate indexes for location, time and object identifier the query optimizer inside a DBMS has to estimate which index is most selective for a given query. It is not possible to use two indexes at the same time – e.g. in case of a space-time query. An approach with one multi-dimensional integrated index does not have this problem. It results in faster query responses when specifying multiple selection criteria; i.e. both search geometry and time interval. We explain the steps needed to make this SFC approach available fully inside a DBMS (to avoid expensive data transfer to external programs during use). The SFC approach makes it possible to better cluster the (spatio-temporal) data compared to an approach with separate indexes. Moreover, we show experiments (with 723,853,597 AIS position report messages spanning 3 months, Sep–Dec 2016, using data for Europe, both on-sea and inland water ways) to compare an approach based on one multi-dimensional integrated index (using a SFC) with non-integrated approach. We analyze loading time (including SFC encoding) and storage requirements, together with the speed of execution of queries and granularity of answers. Conclusion is that time spend on query execution in case of space-time queries where both dimensions are selective using the integrated SFC approach outperforms the non-integrated approach (typically a factor 2–6). Also, the SFC approach saves considerably on storage space (less space needed for indexes). Lastly, we propose some future improvements to get some better query performance using the SFC approach (e.g. IOT, range-glueing and nD-histogram).

An efficient space filling curve based image encryption

There has been an increasing concern for the fast image encryption of multimedia data in the Internet world. The different varieties of encryption methods are introduced to ensure the fast execution, but most of the methods did not improve the speed. In this research work, a simple and the fast image encryption scheme based on Space Filling Curve (SFC) is proposed. The SFC is a method to traverse every pixel of the image continuously and based on that the proposed research work designed a new square-wave confusion and saw-tooth diffusion method for the fast image encryption. Initially, the original image is scrambled by square-wave confusion with different orders and subsequently diffused by saw-tooth diffusion method with different orders. This combination of confusion and diffusion is repeated in many times to obtain the final encrypted image. The experiment results and performance analysis demonstrate that our proposed scheme is a fast and efficient scheme.

Space Filling Approach for Distributed Processing of Top-k Dominating Queries

A top-k dominating query returns k data objects that dominate the highest number of data objects in a given dataset. This query provides us with a set of intuitively preferred data, thus can support a wide variety of multi-criteria decision-making applications, e.g., e-commerce and web search. Due to the growth of data centers and cloud computing infrastructures, the above applications are increasingly being operated in distributed environments. These motivate us to address the problem of distributed top-k dominating query processing. We propose an efficient decentralized algorithm that exploits virtual points and returns the exact answer. The virtual points are utilized to focus on the data space to be preferentially searched and also to limit the search space to prune unnecessary computation and data forwarding. We also propose two other algorithms, which return an approximate answer set while further reducing query processing time. Extensive experiments on both real and synthetic data demonstrate the efficiency and scalability of our algorithms.

CFD study on laminar mixing at a very low Reynolds number by pitching and heaving a square cylinder

In this work, CFD is used to show how the combined motion of heaving and pitching a 2D square cylinder located in the middle of the channel can be used to enhance mixing of two fluids flowing at a very low Reynolds number along a rectangular channel. Both type of motions are applied and enforced with a phase difference at the same time, but at difference frequencies and amplitudes, in order to see if mixing efficiency can be enhance. The characteristics of five governing input parameters and output results are examined. The input parameters consist of two frequencies, one for heaving and one for pitching, and two amplitudes, one for heaving and one for pitching. The output results are mixing efficiency, input power coefficient and mixing energy cost. The Optimal Space Filling algorithm is used to generate 60 different combinations of the input parameters which are used in the numerical studies. Different response surfaces of the output parameters are obtained. It is noted that certain combinations of the input parameters produce the highest mixing efficiency (around 55%), the lowest input power coefficient (around 260 units) or the lowest mixing energy cost (around 13 units) are found. On the other hand a multi-objective optimisation is also carried out in order to find the input parameters that give rise to the highest possible mixing efficiency with lowest possible input power coefficient. A set of optimal solutions leading to Pareto Front is obtained which shows the trade-off between the objectives. Three potential optimal candidates are proposed in this paper.

Mineralogy, geochemistry, and genesis of the volcanic-hosted hydrothermal iron ore deposit in Somea, NW Iran

The Somea iron deposit is located ~ 22 km northwest of Ahar, NW Iran. The lenticular iron ores are formed as open space fillings within the pinch and swell structures of a curved fault in a highly brecciated zone within the host andesitic to dacitic rocks. Fe mineralization comprises magnetite and pyrite in the hypogene zone and hematite, limonite, and goethite in the supergene zone. According to the geochemical analysis results, the average grade of Fe ore is about 53 wt%. Magnetite ore is massive and lenticular in shape. Pyrite is formed as veins/veinlets in the crushed zones and fractures within the magnetite ore, following the continued tectonic movements along the fault. Goethite displays spongy and box-work, as well as botryoidal and colloform textures. Spongy and box-work textures indicate the very high acidity of the leaching fluids, which may be resulted from the oxidation of pyrite veins/veinlets. Banded and colloform textures are produced by colloidal precipitation from fluids. Hematite has formed either due to the alteration of magnetite or by dehydration of goethite at the oxidized zone. The very high Fe/Mn ratio of ore samples may indicate the hypogene genesis of the ore-bearing fluids, which were most likely originated from the neighboring Sheyvardagh granitic–granodioritic intrusion. Sulfur isotopic composition of the pyrite samples reveals a magmatic origin for the ore-bearing fluid and its sulfur content, which further advocates the hydrothermal genesis of the ore body. The δ34S values of the pyrite separates are ranging between − 1.4 and − 0.69‰ (V-CDT).

Space-filling designs for mixtures

Uniform experimental designs (Space Filling Designs) are now widely used with independent variables, particularly in numerical simulation. A lot of construction methods have been developed to uniformly cover the domain of variables, but they remain rarely applied for the study of mixtures. In this article, we propose methods to build space-filling designs for mixtures that can be used to modelize complex phenomena in formulation. Various algorithms like Kennard and Stone, WSP, Strauss and Dmax algorithms, to construct these designs are detailed and compared with respect to uniformity criteria.

Parallel mesh partitioning based on space filling curves

Larger supercomputers allow the simulation of more complex phenomena with increased accuracy. Eventually this requires finer and thus also larger geometric discretizations. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, deformation, adaptation/regeneration or partition/load balance, become a critical issue within the simulation workflow. In this paper we focus on mesh partitioning. In particular, we present a fast and scalable geometric partitioner based on Space Filling Curves (SFC), as an alternative to the standard graph partitioning approach. We have avoided any computing or memory bottleneck in the algorithm, while we have imposed that the solution achieved is independent (discounting rounding off errors) of the number of parallel processes used to compute it. The performance of the SFC-based partitioner presented has been demonstrated using up to 4096 CPU-cores in the Blue Waters supercomputer.

Snapshot Study on the Value of Omentoplasty in Abdominoperineal Resection with Primary Perineal Closure for Rectal Cancer

BackgroundPerineal wound complications are often encountered following abdominoperineal resection (APR). Filling of the pelvic space by omentoplasty (OP) might prevent these complications, but there is scant evidence to support its routine application.ObjectiveThe aim of this study was to evaluate the impact of OP on perineal wound complications.MethodsAll patients undergoing APR with primary perineal closure (PPC) for non-locally advanced rectal cancer in 71 Dutch centers in 2011 were selected from a cross-sectional snapshot study. Outcomes were compared between PPC with or without OP, which was based on variability in practice among surgeons.ResultsOf 639 patients who underwent APR for rectal cancer, 477 had a non-locally advanced tumor and PPC was performed. Of those, 172 (36%) underwent OP. Patients with OP statistically more often underwent an extralevator approach (32% vs. 14%). Median follow-up was 41 months (interquartile range 22–47). There were no significant differences with or without OP in terms of non-healing of the perineal wound at 30 days (47% vs. 48%), non-healing at the end of follow-up (9% vs. 5%), pelvic abscess (12% vs. 13%) or re-intervention for ileus (5% vs. 3%). Perineal hernia developed significantly more often after OP (13% vs. 7%), also by multivariable analysis (odds ratio 2.61, 95% confidence interval 1.271–5.364; p = 0.009).ConclusionsIn contrast to previous assumptions, OP after APR with PPC appeared not to improve perineal wound healing and seemed to increase the occurrence of perineal hernia. These findings question the routine use of OP for primary filling of the pelvic space.

Evolution of the Mineralizing Fluids and Possible Genetic Links between Miduk Porphyry Copper and Latala Vein Type Deposits, Kerman Copper Belt, South Iran

ABSTRACT The Cenozoic Urumieh-Dokhtar Magmatic Belt (UDMB) of Iran is a major host to porphyry Cu-Mo-Au deposits (PCDs), represented by the world-class Sarcheshmeh deposit and Miduk deposit in the south and the Sungun deposit in the north. Vein type, base and/or precious metal deposits are also common and some are spatially associated with PCDs. Latala and Chahmessi are vein type, base and precious metal deposits in the north and southwest Miduk deposit. The area is covered mainly by Paleocene-Eocene volcanic and pyroclastic rocks of basaltic, basaltic-andesitic and trachy-andesitic compositions, and minor marls and limestones. The volcanic and pyroclastic rocks are intruded by Miocene shallow intrusions of quartz diorite, quartz monzonite and granodiorite compositions.The rocks are host to a set of ore-bearing quartz veins. Mineralization in both the Chahmessi and Latala deposits are controlled by faults and fractures. The role of the ring structures and faults in the distribution of hydrothermal alteration zones and mineralization is important in the Latala deposit. In these veins, euhedral quartz with sulfide mineralization occurs as open space fillings, minor replacement bodies and hydrothermal breccia. The veins consist of quartz, calcite, pyrite, chalcopyrite, galena, sphalerite, bornite and minor sulfosalts, particularly enargite. According to studies based on fluid inclusions in the Miduk porphyry, three types of fluids are responsible for mineralization. Homogenization temperatures and salinity in porphyry-type fluids vary from 566 to 162 °C and 61.3 to 1.2 wt% NaCl equiv. For the Latala vein type base and precious metals deposit, homogenization temperature and salinity vary from 380 to 131 °C and 10.6 to 0.17 wt% NaCl equiv. The gas phase in fluid inclusions of Latala is dominated by CO2 but also shows the presence of CO and H2, characterizing reducing conditions associated with ore deposition. The change from lithostatic to hydrostatic regime, boiling and fluid dilution associated with the introduction of meteoric fluids provides an explanation for the widespread Th and salinity data. Calculated pressure for examples of Miduk fluid inclusions varies from 700 to 200 bars. These pressures correspond to depths of 2500 to 1500 metres for porphyry mineralization. The three-phase fluid inclusions, corresponding to magmatic fluid, show the highest pressure. The Latala base and precious metals deposit has formed at pressures between 200 and 100 bars, corresponding to a depth of less than 1 km. Sphalerite mineralization occurs in shallow parts of the sedimentary-volcanic sequence from magmatic fluids diluted by meteoric fluids and also occurs in more distal parts of the porphyry. The sulphur isotopic composition for sulfide minerals varies between -9.8 and -1.0‰, which correspond to values of magmatic sulfur. This suggests that magmatic water was responsible for transportation of metals in Latala. Epithermal mineral precipitation occurred upon dilution of the low-salinity magmatic fluid with meteoric water, which entered the hydrothermal system as it cooled and successively diluted during continued magmatic fluid ascent.

An efficient adaptive database sampling strategy with applications to eddy current signals

Computer simulations are widely used in engineering domains to model complex scenarios and extract meaningful information or improve the understanding of a given problem. Common purposes of simulation studies are inversion, optimization, sensitivity analysis and evaluation of performance. In such contexts, it is often convenient to replace the time consuming forward solver by a metamodel acting as a fast and accurate substitute in a restricted range of input parameters. Focused on applications in the field of Electromagnetic-Non Destructive Testing (E-NDT), this paper proposes an approach to design robust metamodels, based on adaptive databases of simulation results in order to ensure their accuracy. They can then be used as real-time emulators of the physical model and considerably speed up time consuming studies like estimation of probability of detection, defect characterization or sensitivity analysis. The database and metamodel generation problem is first addressed with a meshless approach based on Augmented Radial Basis Function (A-RBF) algorithm. Then, its performance is compared with that of a more standard approach exploiting a n-dimensional Delaunay mesh. Both approaches rely on an adaptive generation technique known in the literature as Output Space Filling (OSF). Performance in terms of computational time and results accuracy of both methods are finally evaluated and compared in the case of a specific application: the simulation of Eddy Current Testing (ECT) inspection problems.

کانه زایی مس- نقره سولفید توده ای آتشفشان زاد نوع بشی در توالی آتشفشانی- رسوبی کرتاسه پسین: مثال موردی کانسار گرماب پایین، جنوب شرق شاهرود

کانسار مس- نقره گرماب پایین در توالی آتشفشانی- رسوبی کرتاسه پسین زیر پهنه سبزوار واقع ‌شده است. کانه زایی به شکل هندسی چینه‌سان و چینه‌کران در افق چینه‌ای خاص به همراه نهشته‌های برون‌دمی رخ‌داده است. سنگ میزبان کانه زایی را سنگ‌های آتشفشانی آندزیتی- داسیتی و آذرآواری‌های وابسته تشکیل می‌دهند. کانه زایی از کمرپایین به سمت کمربالا در چهار رخساره رگه- رگه‌چه ای، توده‌ای- نیمه توده‌ای، لایه‌ای و رسوبات برون‌دمی رخ‌داده است. کانی‌شناسی ماده معدنی شامل کانی‌های اولیه نظیر پیریت، مگنتیت و کالکوپیریت و کانی‌های ثانویه نظیر مس طبیعی، مالاکیت، کوپریت، کولیت و اکسیدهای آهن- منگنز است. دگرسانی سنگ دیواره، به‌طور عمده از نوع کلریتی و به مقدار کمتر شامل سیلیسی، آرژیلیتی و زئولیتی است. حداکثر عیار طلا و نقره در کانسار به ترتیب 1 و 19 گرم در تن است. به نظر می‌رسد که بروز فعالیت آتشفشانی زیردریایی در یک حوضه پشت‌کمانی در کرتاسه پسین، به تشکیل این کانسار سولفید توده‌ای نوع بشی منجر شده است.

Geological and geochemical constraints on the Cheshmeh-Frezi volcanogenic stratiform manganese deposit, southwest Sabzevar basin, Iran

The Cheshmeh-Frezi Mn deposit belongs to the southwest Sabzevar basin to the north of the Central Iranian microcontinent. This basin, which hosts abundant mineral deposits including Mn exhalative and Besshi-type Cu-Zn volcanogenic massive sulfide deposits, followed an evolution closely related to the subduction of the Neo-Tethys oceanic crust beneath the Central Iranian microcontinent. Two major sedimentary sequences are recorded within this basin: (I) the Lower Late Cretaceous volcano-sedimentary sequence (LLCVSS) and (II) the Upper Late Cretaceous sedimentary dominated sequence (ULCSS). The Cheshmeh-Frezi Mn deposit is hosted within red tuff with interbeds of green tuffaceous sandstone of the LLCVSS. Mineralization occurs as stratiform blanket-like and tabular orebodies. Psilomelane, pyrolusite and braunite are the main minerals of the ore, which display a variety of textures. Such as layered, laminated, disseminated, massive, replacement or open space fillings. The footwall and hanging-wall volcanic rocks are predominantly andesite and trachyandesite rocks. Footwall and hangingwall volcanic rocks at Cheshmeh-Frezi are enriched in light rare earth elements (LREEs) compared to chondrite, have steep REE patterns, and generally show Ta and Nb depletions relative to chondrite which are characteristic of back-arc environments. The significant geochemical characteristics of ore such as high Mn content (12.41–33.14 wt%; average 19.41 wt%), low concentration of Fe (0.64–2.27 wt%; average 1.63 wt%), high Ba (49.7–9901ppm, average 2728.67ppm), LREE>HREE, and negative Ce and Eu anomalies reveal a primary distal hydrothermal-exhalative source for mineralization. Cheshmeh-Frezi deposit, in comparison with different types of volcanogenic manganese deposits shows broad similarities with the Cuban-type Mn deposits such as tectonic, host and associated rock types, geometry, textures, structures, mineralogy and lithogeochemistry.

Planning of Ultra-Dense Wireless Networks

Fifth generation (5G) wireless networks adopt the deployment of ultra-dense small cells for efficient slicing of radio resources. This conceptual change in network structure aims to meet the rapid increase in mobile data traffic and connected devices. However, limited free spectrum and dynamic assignment of resources are main concerns when considering the cognitive small cells solution. Therefore, there is a need to map traffic patterns with the number of cognitive small cells to provide an optimized network architecture operating with adequate spectrum resources. This article investigates the case when network densification exceeds the radio resource capacity, causing a large scale overlapping in cell coverage area and used channels. Taking into consideration cognitive network performance characteristics, we identify two spectrum coexistence frameworks, Space Filling and Time Filling, to improve spectrum utilization and scalability for moderately large networks. Simulations show that there is a turning point when network performance starts to decline as the number of cognitive small cells exceeds the shared resources in a site area, subject to a certain load profile. This optimization of network structure, based on spectrum transmission opportunities, brings about a new topic for operators and research communities considering small cells operating in the unlicensed band.

M-Grid: a distributed framework for multidimensional indexing and querying of location based data

The widespread use of mobile devices and the real time availability of user-location information is facilitating the development of new personalized, location-based applications and services (LBSs). Such applications require multi-attribute query processing, scalability for supporting millions of users, real-time querying capability and analyzing large volumes of data. Cloud computing aided a new generation of distributed databases commonly known as key-value stores. Key-value stores were designed to extract values from very large volumes of data while being highly available, fault-tolerant and scalable, hence providing much needed infrastructure to support LBSs. However, complex queries over multidimensional data cannot be processed efficiently as they do not provide means to access multiple attributes. In this paper, we present M-Grid, a unifying indexing and a data distribution framework which enables key-value stores to support multidimensional queries. We organize a set of nodes in a modified P-Grid overlay network which provides efficient data distribution, fault-tolerance and query processing over multidimensional data. To index, we use Hilbert Space Filling Curve based linearization technique which preserves the data locality to efficiently manage multidimensional data in a key-value store. We propose algorithms to dynamically process range and k nearest neighbor (kNN) queries on linearized values. This removes the overhead of maintaining a separate index table. Our approach is completely independent from the underlying storage layer and can be implemented on any cloud infrastructure. Our experiments on Amazon EC2 show that M-Grid achieves a performance improvement of three orders of magnitude in comparison to MapReduce and four times to that of MD-HBase scheme.