Map Symbols Research Articles

EXIT-Chart Aided Design of Row-Permutation Assisted Twin-Interleaver BICM-ID

Twin-interleaver bit-interleaved LDPC coded modulation (BICM) has been widely adopted and studied in the context of digital terrestrial transmission (DTT) systems. Extrinsic-information transfer (EXIT) charts have been used as an analysis tool to evaluate the iterative decoding performance and to design a twin-interleaver BICM system. Since BICM using iterative decoding (BICM-ID) exhibits capacity-approaching decoding performance, developing the conventional twin-interleaver BICM DTT system to a BICM-ID system has also been attempted. When considering the twin-interleaver BICM-ID systems, there are a couple of aspects that should be taken into account. We will demonstrate that anti-Gray mapping should be adopted for improving the iterative decoding performance instead of the classic Gray symbol mapping. However, the previous literature related to designing the associated row-permutation interleaver (RPI) was mainly focused on BICM systems relying on Gray mapping. Hence, we will design the RPI of the twin-interleaver BICM-ID DTT systems using an anti-Gray mapping. Explicitly, we use: 1) the EXIT-chart analysis that accurately visualizes the overall iterative decoding and demapping performance of the twin-interleaver BICM-ID DTT systems using anti-Gray mapping and 2) a preprocessing stage for eliminating duplicate RPI candidates by using a parameter that roughly predicts the EXIT-chart analysis result before the EXIT-chart analysis is involved. By the elimination of the duplicates, over 99% of the initial candidates of the RPIs can be removed from the original M! candidates, where M stands for the number of modulated bits in a symbol. Given this drastically reduced number of candidates, the proposed design method finds novel RPIs, having superior bit-error ratio performances over the conventional RPIs in the context of the DVB-T2 standard.

Precoded MIMO Systems With Nonbinary LDPC Codes and Many-to-One Mapping

A precoding design is proposed for multiple-input multiple-output (MIMO) systems utilizing nonbinary low-density parity check (NB-LDPC) codes and many-to-one mapping. When a high-order modulation scheme is used, many-to-one mapping converts a group of low-order Galois field (GF) coded symbols into one modulated MIMO symbol vector. In contrast, one-to-one mapping maps a high-order modulation symbol directly from one high-order GF coded symbol. With the help of an interleaver between the NB-LDPC encoder and the GF to MIMO symbol mapper, the many-to-one mapping enables turbo receiver and reduces the computational complexity by more than 95%. The proposed MIMO precoders enhance the error-rate performance of the many-to-one NB-LDPC MIMO system, especially in terms of reducing the error floor and improving the waterfall region. The proposed precoder design modifies the approach that suboptimally maximizes the minimal Euclidean distance between the received MIMO symbols. Simulation results show that the proposed precoders enhance the robustness of the precoder design and reduce the inner and outer iterations of the turbo receiver.

Dynamic QAM Mapping for Physical-Layer Security Using Digital Chaos

This paper proposes and experimentally demonstrates a physical-layer data encryption scheme using multi-fold chaotic mapping of quadrature amplitude modulation (QAM) symbols in orthogonal frequency-division-multiplexed passive optical network (OFDM-PON). Dynamic radius and phase offsets are added in the standard QAM during QAM mapping on constellation using digital chaos. Due to the dynamic chaotic radius and phase offsets, the QAM symbols are mapped over the entire constellation plane, and thus the random, flexible QAM mapping is reconstructed to provide high-level security during data transmission. Since the chaotic offsets along with the data permutations are independently predetermined by a hyper digital chaos, the multi-fold data encryption creates an overall key space of ~10340 to enhance the physical-layer security. Successful transmission experiment of 9.4-Gb/s, 16-QAM encrypted OFDM data is demonstrated over a 22-km standard single-mode fiber in OFDM-PON. Moreover, with the use of dynamic mapping of QAM symbols, the transmission performance is not significantly degraded after implementing the proposed multi-fold secure data encryption.

Designing the historical atlas «Holocoust in Ukraine (1941-1944)»

This article contains main information on designing the historical atlas of the Holocaust in Ukraine. The goal of creating the atlas is to demonstrate preconditions, progress and aftermath of the Holocaust in Ukraine. During the analysis of the sources of historical information about Holocaust, the authors found two atlases, which contained maps of the Holocaust in Europe: Martin Gilbert’s «The Routledge Atlas of the Holocaust» and «Historical Atlas of the Holocaust» created by the United States Holocaust Memorial Museum. Developments of the Holocaust in Ukraine are classified by location and chronology in three stages: escalation of the Holocaust in Ukraine (1941), mass extermination of Jews (1942), the final solution to the Jewish question (1943-1944). The process of the atlas design includes creating system of map’s symbols, arrangement of maps, design of different elements of cartographic images and pages of atlas. There two types of map’s symbols: general geographic and thematic. Thematic map symbols are distributed by frequency of use into commonly used and special. The creation of the map’s symbols is based on three statements: associativity, unambiguousness and equipment with explanations (optional). The designed atlas has five chapters: «Ukraine in advance of the Holocaust», «Escalation of the Holocaust in Ukraine», «Mass extermination of Jews», «The final solution to the Jewish question» and «Aftermath of the Holocaust in Ukraine». According to a dramatic conception of the atlas themes, there are used two color models: CMYK (for cartographic elements and symbols on maps) and Grayscale (design of pages and additional material). The atlas project is accompanied by a series of maps, which demonstrates semantic and design features of it.

An accessible Brno city centre for people with impaired mobility

ABSTRACTAccessibility mapping is an emerging initiative across the world since people with impaired mobility are becoming more and more integrated into mainstream society. People with impaired mobility include, for example, wheelchair users, elderly people, pregnant women, or people with babies in prams or with children under three years of age. They can constitute up to 30% of the population. This paper therefore aims at creating the map for the ‘Accessibility Guide to Brno City Centre for People with Limited Mobility’ published in a paper and on the Web by Brno City Municipality (Czech Republic) in cooperation with Masaryk University between 2012 and 2016. Issues with respect to methodology, visualisation, as well as perception are discussed (Main Map). The developed map presents complex information about the accessibility of buildings in Brno city centre. General accessibility is displayed by specially developed map symbols presenting two types of information, quantitative information, i.e. the level of accessibility, and qualitative information, i.e. the type of the location.

Bi-orthogonal Symbol Mapping and Detection in Optical CDMA Communication System

AbstractIn this paper, the bi-orthogonal symbol mapping and detection scheme is investigated in time-spreading wavelength-hopping optical CDMA communication system. The carrier-hopping prime code is exploited as signature sequence, whose put-of-phase autocorrelation is zero. Based on the orthogonality of carrier-hopping prime code, the equal weight orthogonal signaling scheme can be constructed, and the proposed scheme using bi-orthogonal symbol mapping and detection can be developed. The transmitted binary data bits are mapped into corresponding bi-orthogonal symbols, where the orthogonal matrix code and its complement are utilized. In the receiver, the received bi-orthogonal data symbol is fed into the maximum likelihood decoder for detection. Under such symbol mapping and detection, the proposed scheme can greatly enlarge the Euclidean distance; hence, the system performance can be drastically improved.

Symbolic Multi-Level Loop Mapping of Loop Programs for Massively Parallel Processor Arrays

Today’s MPSoCs (multiprocessor systems-on-chip) have brought up massively parallel processor array accelerators that may achieve a high computational efficiency by exploiting multiple levels of parallelism and different memory hierarchies. Such parallel processor arrays are perfect targets, particularly for the acceleration of nested loop programs due to their regular and massively parallel nature. However, existing loop parallelization techniques are often unable to exploit multiple levels of parallelism and are either I/O or memory bounded. Furthermore, if the number of available processing elements becomes only known at runtime—as in adaptive systems—static approaches fail. In this article, we solve some of these problems by proposing a hybrid compile/runtime multi-level symbolic parallelization technique that is able to: (a) exploit multiple levels of parallelism as well as (b) different memory hierarchies, and (c) to match the I/O or memory capabilities of the target architecture for scenarios where the number of available processing elements is only known at runtime. Our proposed technique consists of two compile-time transformations: (a) symbolic hierarchical tiling followed by (b) symbolic multi-level scheduling. The tiling levels scheduled in parallel exploit different levels of parallelism, whereas the sequential one, different memory hierarchies. Furthermore, by tuning the size of the tiles on the individual levels, a tradeoff between the necessary I/O-bandwidth and memory is possible, which facilitates obeying resource constraints. The resulting schedules are symbolic with respect to the problem size and tile sizes. Thus, the number of processing elements to map onto does not need to be known at compile time. At runtime, when the number of available processors becomes known, a simple prologue chooses a feasible schedule with respect to I/O and memory constraints that is latency-optimal for the chosen tile size. In summary, our approach determines the set of feasible, latency-optimal symbolic loop schedule candidates at compile time, from which one is dynamically selected at runtime. This approach exploits multiple levels of parallelism, is independent of the problem size of the loop nest, and thereby avoids any expensive re-compilation at runtime. This is particularly important for low cost and memory-scarce embedded MPSoC platforms that may not afford to host a just-in-time compiler.

Geovisualizing attribute uncertainty of interval and ratio variables: A framework and an implementation for vector data

Geovisualization of attribute uncertainty helps users to recognize underlying processes of spatial data. However, it still lacks an availability of uncertainty visualization tools in a standard GIS environment. This paper proposes a framework for attribute uncertainty visualization by extending bivariate mapping techniques. Specifically, this framework utilizes two cartographic techniques, choropleth mapping and proportional symbol mapping based on the types of attributes. This framework is implemented as an extension of ArcGIS in which three types of visualization tools are available: overlaid symbols on a choropleth map, coloring properties to a proportional symbol map, and composite symbols.

High Power Efficient Quadrature Amplitude Modulation Soft Decision Algorithm

The quadrature amplitude modulation (QAM) is the basic technology on high speed broadband communication physical level symbol mapping. Systems requiring lower signal to noise ratio to achieve the same error probability are more power-efficient. The usage of high order modulation is limited due to its low power efficiency compared to lower order modulation. This paper combines the characteristics of Gray code symbol mapping for QAM constellation to design a soft decision algorithm based on signal diversity (div-log-MAP). The bottle-neck of the low power efficiency is overcome and highest power efficiency can be realized. The performance of div-log-MAP can beyond the performance of log maximum a posteriori probability algorithm. At the same time, the proposed algorithm is a more effective method to utilize high order QAM modulation on high speed broadband communication.

An Automated Displaced Proportional Circle Map Using Delaunay Triangulation and an Algorithm for Node Overlap Removal

Proportional circle maps are a popular method for visualizing quantitative data on a map. Circles are scaled proportionally based on the data provided; larger circles represent larger quantities. The circles require two values, a location and a numeric quantity. For data that have a wide range of values, the resulting map will produce clutter and overlap in which large symbols obscure the information contained in smaller circles. Some previous solutions to this problem are modifying and improving the contrast between symbols, or using stacking algorithms so all symbols are visible. This article proposes the displaced proportional symbol map, which displaces the symbol's location based on the amount of overlap between neighbouring circles. At the same time, it preserves the location of non-overlapping symbols, which distinguishes it from the circular cartogram. The displacement is automated through the proximity stress model algorithm for node overlap removal. This algorithm was originally designed for graph layouts with overlapping nodes, but was modified here for circular symbols and map layout. The result is a map with improved clarity and the ability to add labelling to a cluttered proportional circle map.

Картографирование ландшафтно-экологической ситуации территории горнодобычи в пределах Патомского нагорья

The article presents the results of a landscape-ecological study with mapping of the territory in the central part of the Patom upland. Research polygon is located within the Kropotkinsky mining unit of Baikal region, has an area of 600 km2. Technogenic disruption has a wide spatial and temporal distribution. Analysis of a complex ecological situation requires a rational assessment and adequate mapping. For this, modern geoinformation-cartographic, remote methods and a geosystemic approach were used. A large-scale thematic map was created, which includes 250 polygons in the main layer, which belong to 26 types of landscapes. A detailed description of the landscapes is given in the map legend. There are indicated the belonging to the landscape structures of regional and continental dimension, types and degree of disturbance. Additional vector layers are selected for displaying exogenetic geological processes, linear disturbance, geochemical anomalies. Mapsemiotic method was used for the visualization and formalization of the final thematic map. It allows to make full use of the integrated capabilities of the syntax of the map symbols and their semantic value in the software environment.

Web mapping application of Roman Catholic Church administration in the Czech lands in the early modern period

<p class="western"><span style="color: #00000a;"><span lang="en-GB">Reconstruction of historical spatial relationships is still a topical issue in historical geography. In this respect, the Church history has not been well explored. The parish administration in the Czech lands is evolving since the advent of Christianity in 863, and a number of reforms have passed over the centuries. Significant changes in the administration also underwent during recatholisation of the Czech lands in the 17th</span></span><span style="color: #00000a;"><span lang="en-GB"> and 18th</span></span><span style="color: #00000a;"><span lang="en-GB">century. From this Baroque era, there are written sources which have been preserved, so they can be utilized to reconstruct historical Church administration in the form of web mapping application. The paper briefly introduces methods which were used to build a spatial database filled with historical data. However, the main outcome of this paper is to describe the creation of the web mapping application that provides visualisation of this data. Discussed are topics like cartographic project, choice of map symbols, data generalization for different levels of detail and placement of annotations. Display of cartographic data were performed using the ArcGIS platform, through a combination of map tiles and feature services that are bundled into the application template created in Web AppBuilder.</span></span></p>

A new inter‐carrier interference self‐cancellation mapping scheme over fast time‐varying fading channels

A new inter-carrier interference self-cancellation method with the data symbol mapping scheme of differential grouping weighted symmetry data-conjugate is studied and proposed to raise the bandwidth efficiency and further improve the system performance over fast time-varying fading channels. Comparing with the other existing self-cancellation methods, the proposed scheme can not only maintain the same bandwidth efficiency as the original orthogonal frequency division multiplexing system, but also show a better performance on carrier-to-interference ratio and bit error rate according to the final simulation results and performance analysis.

Construction of collaborative mapping engine for dynamic disaster and emergency response

In the collaborative mapping of disasters, response situations and decisions, it is important to support various emergency responders with a unified platform to help in decision making and coordinating emergency action. However, most existing symbol libraries focus primarily on representing disasters and related information. These libraries lack specific symbols to map response situations and emergency decisions. For representation of dynamic disasters and response factors, these symbols support rich interactive editing after the symbols are mapped. In addition, decision making and mapping of disasters and response situations typically involve different domains of expertise and different responsibilities of map makers. It is essential to construct a collaborative mapping engine that supports disaster and emergency mapping on a collaborative platform. However, most existing methods of collaboration cannot readily support collaboration on symbols containing complex data structures or accommodate rich interactive editing operations. This article proposes a collaborative mapping engine for dynamic disasters and emergency responses. To support collaborative mapping based on complex data structures and rich interactive map symbols, it proposes a method of mapping operation replication to implement collaboration. Additionally, strategies were designed to enhance the efficiency and stability of collaboration. Finally, an experiment was conducted using the Wenchuan earthquake as an example. The results reveal that the engine can contribute to improved mapping efficiency and management during emergencies.

Delineation of an endemic tick paralysis zone in southeastern Australia

Tick paralysis has a major impact on pet dog and cat populations in southeastern Australia. It results from envenomation by Ixodes holocyclus and Ixodes cornuatus ticks, the role of Ixodes cornuatus in the epidemiology of this disease in Australia being unclear. The aim of this study was to describe the geographical distribution of tick paralysis cases in southeastern Australia using data from a national disease surveillance system and to compare characteristics of “endemic” cases with those reported outside this endemic zone (“sporadic” cases). Data were collated and a proportional symbol map of all cases by postcode was created. A 15-case isopleth was developed based on descriptive spatial statistics (directional ellipses) and then kernel smoothing to distinguish endemic from sporadic cases. During the study period (January 2010–December 2015) 12,421 cases were reported, and 10,839 of these reported by clinics located in 434 postcodes were included in the study. Endemic cases were predominantly reported from postcodes in coastal southeastern Australia, from southern Queensland to eastern Victoria. Of those cases meeting selection criteria, within the endemic zone 10,767 cases were reported from 351 (88%) postcodes and outside this zone 72 cases were reported from 48 (12%) postcodes. Of these latter 48 postcodes, 18 were in Victoria (26 cases), 16 in New South Wales (28 cases), 7 in Tasmania (9 cases), 5 in South Australia (7 cases) and 2 in Queensland (2 cases). Seasonal distribution in reporting was found: 62% of endemic and 52% of sporadic cases were reported in spring. The number of both endemic and sporadic cases reported peaked in October and November, but importantly a secondary peak in reporting of sporadic cases in April was found. In non-endemic areas, summer was the lowest risk season whilst in endemic areas, autumn was the lowest risk season. Two clusters of sporadic cases were identified, one in South Australia (P=0.022) during the period 22 May to 2 June 2012 and another in New South Wales (P=0.059) during the period 9 October to 29 November 2012. Endemic and sporadic cases did not differ with respect to neuter status (P=0.188), sex (P=0.205), case outcome (P=0.367) or method of diagnosis (P=0.413). However, sporadic cases were 4.2-times more likely to be dogs than cats (P<0.001). The endemic tick paralysis zone described is consistent with previous anecdotal reports. Sporadic cases reported outside this zone might be due to a history of pet travel to endemic areas, small foci of I. holocyclus outside of the endemic zone, or in the case of southern areas, tick paralysis caused by I. cornuatus.

High performance gain demodulate system for hybrid fiber-coaxial

Gigabit capable of Hybrid Fiber-Coaxial (HFC) represented an increase. The goals of the next generation HFC system are to efficiently utilize the precious last 100m of the coaxial cable and to achieve a Gigabit transmission rate. This target demands higher requirements regarding the physical layer (PHY) throughput. Firstly, the PHY architecture of next generation HFC system is given in detail. Secondly, in order to meet challenging high PHY throughput, a class of Low Density Parity Check (LDPC) code is selected as the Forward Error Correction (FEC) scheme, the ultimate choice is made on the basis of system with a better bit error rate performance. Finally, this paper combines the characteristics of Gray code symbol mapping for Quadrature Amplitude Modulation (QAM) constellation to design a soft decision algorithm based on signal diversity. Especially in terms of power efficiency, this algorithm can beyond the performance of log-MAP algorithm.

Narrativas y memoria

La memoria, como relato que revela las huellas que los acontecimientos históricos dejan en un colectivo, se negocia dentro de dicho colectivo para dar cuenta de su espíritu, de su identidad. De esta manera, los diálogos interculturales, que permiten dinamizar las culturas que dialogan, se construye a partir de la comprensión que cada cultura tiene de sí misma y de la otra, con fundamento en los relatos.La memoria se usa, entonces, para administrar el tiempo y para dosificar el olvido, con el propósito de realizar pactos con la vida. Entre una memoria literal y una memoria ejemplar, las culturas se debaten para ir venciendo el miedo que produce amnesia, y la hipermemoria que impide el perdón.No hay posibilidad de acción colectiva sin vínculos identitarios, sin memoria vinculante, sin el sentimiento de pertenencia a un relato donde cada quien se ubica en un mapa simbólico. Y, al mismo tiempo, no hay dinámica productiva si los elementos con los cuales se construye la identidad no se dejan interrogar por aquello que existe fuera de sus fronteras simbólicas.Una comunidad que se da críticamente una memoria puede actuar sobre su futuro, es decir, es una comunidad que puede trazar un proyecto en una función perlaborativa de la memoria.

Towards an efficient indoor navigation system: a near field communication approach

PurposeThis research aims to focus on providing interventions to alleviate usability challenges to strengthen the overall accuracy and the navigation effectiveness in indoor and stringent environments through the experiential manipulation of technical attributes of the positioning and navigation system.Design/methodology/approachThe study followed a quantitative and experimental method of empirical enquiry and software engineering and synthesis research methods. The study further entails three implementation processes, namely, map generation, positioning framework and navigation service using a prototype mobile navigation application that uses the near field communication (NFC) technology.FindingsThe approach and findings revealed that the capability of NFC in leveraging its low-cost infrastructure of passive tags, its availability in mobile devices and the ubiquity of the mobile device provided a cost-effective solution with impressive accuracy and usability. The positioning accuracy achieved was less than 9 cm. The usability improved from 44 to 96 per cent based on feedbacks given by respondents who tested the application in an indoor environment. These showed that NFC is a viable alternative to resolve the challenges identified in previous solutions and technologies.Research limitations/implicationsThe major limitation of the navigation application was that there is no real-time update of user position. This can be investigated and extended further by using NFC in a hybrid make-up with WLAN, radio-frequency identification (RFID) or Bluetooth as a cost-effective solution for real-time indoor positioning because of their coverage and existing infrastructures. The hybrid positioning model, which merges two or more techniques or technologies, is becoming more popular and will improve its accuracy, robustness and usability. In addition, it will balance complexity, compensate for the limitations in the technologies and achieve real-time mobile indoor navigation. Although the presence of WLAN, RFID and Bluetooth technologies are likely to result in system complexity and high cost, NFC will reduce the system’s complexity and balance the trade-off.Practical implicationsWhilst limitations in existing indoor navigation technologies meant putting up with poor signal and poor communication capabilities, outcomes of the NFC framework will offer valuable insight. It presents new possibilities on how to overcome signal quality limitations at improved turn-around time in constrained indoor spaces.Social implicationsThe innovations have a direct positive social impact in that it will offer new solutions to mobile communications in the previously impossible terrains such as underground platforms and densely covered spaces. With the ability to operate mobile applications without signal inhibitions, the quality of communication – and ultimately, life opportunities – are enhanced.Originality/valueWhile navigating, users face several challenges, such as infrastructure complexity, high-cost solution, inaccuracy and usability. Hence, as a contribution, this paper presents a symbolic map and path architecture of a floor of the test-bed building that was uploaded to OpenStreetMap. Furthermore, the implementation of the RFID and the NFC architectures produced new insight on how to redress the limitations in challenged spaces. In addition, a prototype mobile indoor navigation application was developed and implemented, offering novel solution to the practical problems inhibiting navigation in indoor challenged spaces – a practical contribution to the community of practice.

Experimental Evaluation of the Usability of Cartogram for Representation of GlobeLand30 Data

GlobeLand30 is the world’s first global land cover dataset at 30 m resolution for two epochs, i.e., 2000 and 2010. On the official website, the data are represented by qualitative thematic maps which show the distribution of global land cover, and some proportional symbol maps which are quantitative representations of land cover data. However, researchers have also argued that the cartogram, a kind of value-by-area representation, has some advantages over these maps in some cases, while others doubt their usability because of the possible distortion in shape. This led us to conduct an experimental evaluation of the usability of the cartogram for the representation of GlobeLand30. This experimental evaluation is a comparative analysis between the cartogram and the proportional symbol map to examine which is more effective in various kinds of quantitative analyses. The results show that the thematic map is better than the cartogram for the representation of quantity (e.g., area size), but the cartogram performs better in the representation of tendency distribution and areas’ multiple relationships. The usability of the cartogram is notably affected by map projection and the irregularity in area shapes, but the equal-area projection does not necessarily perform better than equidistance projection, especially at high latitudes.

Generating Tile Maps

AbstractTile maps are an important tool in thematic cartography with distinct qualities (and limitations) that distinguish them from better‐known techniques such as choropleths, cartograms and symbol maps. Specifically, tile maps display geographic regions as a grid of identical tiles so large regions do not dominate the viewer's attention and small regions are easily seen. Furthermore, complex data such as time series can be shown on each tile in a consistent format, and the grid layout facilitates comparisons across tiles. Whilst a small number of handcrafted tile maps have become popular, the time‐consuming process of creating new tile maps limits their wider use. To address this issue, we present an algorithm that generates a tile map of the specified type (e.g. square, hexagon, triangle) from raw shape data. Since the ‘best’ tile map depends on the specific geography visualized and the task to be performed, the algorithm generates and ranks multiple tile maps and allows the user to choose the most appropriate. The approach is demonstrated on a range of examples using a prototype browser‐based application.