An Improved HVQ Algorithm for Compression and Rendering of Space Environment Volume Data with Multi-correlated Variables

Volume visualization can not only illustrate overall distribution but also inner structure and it is an important approach for space environment research.Space environment simulation can produce several correlated variables at the same time.However,existing compressed volume rendering methods only consider reducing the redundant information in a single volume of a specific variable,not dealing with the redundant information among these variables.For space environment volume data with multi-correlated variables,based on the HVQ-1d method we propose a further improved HVQ method by compositing variable-specific levels to reduce the redundant information among these variables.The volume data associated with each variable is divided into disjoint blocks of size 43 initially.The blocks are represented as two levels,a mean level and a detail level.The variable-specific mean levels and detail levels are combined respectively to form a larger global mean level and a larger global detail level.To both global levels,a splitting based on a principal component analysis is applied to compute initial codebooks.Then,LBG algorithm is conducted for codebook refinement and quantization.We further take advantage of progressive rendering based on GPU for real-time interactive visualization.Our method has been tested along with HVQ and HVQ-1d on high-energy proton flux volume data,including>5,>10,>30 and>50 MeV integrated proton flux.The results of our experiments prove that the method proposed in this paper pays the least cost of quality at compression,achieves a higher decompression and rendering speed compared with HVQ and provides satisficed fidelity while ensuring interactive rendering speed.

Experimental study on thermal environment in large-space building with low sidewall air supply

The thermal environmental characteristics are experim-entally studied in terms of different air supply volumes and outdoor meteorological parameters in a large-space building which is air conditioned with a low sidewall air supply.The experimental results show that the indoor vertical temperature distributions under different condition are similar.The maximum vertical temperature difference（MVTD）is up to about 20 ℃,and it linearly changes with the sol-air temperature.The indoor vertical temperature gradients（VTGs）in the upper,central and lower zones are different.The influence of the sol-air temperature on the VTGs in the upper and the lower zones is greater than that in the central zone.The characteristics of the VTGs in the three zones affected by the air supply volume are the same as those affected by the sol-air temperature.Besides,because of the small air velocity,the predicted mean vote（PMV）on comfort in the occupied zone is slightly high and the air temperature difference between the head and the ankle is usually more than 3 ℃.

Protective Measures for Space Environment of Time-honored Brands——With Xi'an City as a Study Case

Based on the field survey and analysis of representative traditional time-honored shops in Xi'an City,specific measures for protecting their space environment were put forward,and the sustainable preservation and development pattern of such intangible cultural heritages in the future urban development was established.

Nonlinear dynamics of flexible tethered satellite system subject to space environment

The paper studies the nonlinear dynamics of a flexible tethered satellite system subject to space environments, such as the J2 perturbation, the air drag force, the solar pressure, the heating effect, and the orbital eccentricity. The flexible tether is modeled as a series of lumped masses and viscoelastic dampers so that a finite multi- degree-of-freedom nonlinear system is obtained. The stability of equilibrium positions of the nonlinear system is then analyzed via a simplified two-degree-freedom model in an orbital reference frame. In-plane motions of the tethered satellite system are studied numerically, taking the space environments into account. A large number of numerical simulations show that the flexible tethered satellite system displays nonlinear dynamic characteristics, such as bifurcations, quasi-periodic oscillations, and chaotic motions.

Fieldwork Test Research of the Impact on Building Physical Environment on Six Types of Atrium Space in Cold Climates

Since the research on verification to passive design strategies in sustainable building is at the initial stage,and its test method and verification conclusion are not scientific enough to validate,this paper proposes the necessity of building physical environmental monitoring to quantitative optimization of passive strategies efficiency from the perspective of architecture design and building environment. Adopting comparative research method,this research chooses six types of atrium space in cold climate in China as a prototype,focusing on building physical environmental performance difference in and between atrium and building main space. Spatial parameters of the atrium space will be divided into four factors: spatial geometry,interfacial properties,internal and external related categories. With subdividing these four factors into sub-factors,this paper makes crosscomparison among the sub-factors to clarify passive strategies effectiveness in atrium. Data comparison analysis shows that Winter atrium passive strategy in cold regions from traditional view is not obvious in practical application,and test data need to be stratified refined in atrium design in case of optimizing passive strategy from building prototype perspective.

Urban Green Spaces and an Integrative Approach to Sustainable Environment

This paper explains the benefits and challenges of urban green spaces based on the critical discussion of study results from different studies in different cities. The important roles played by green spaces are social, economic, cultural and environmental aspects of sustainable development. Urban green spaces can be a comprehensive tool for long term protection of environmental sustainability through improving the quality of life and air quality, increasing property value due to their amenity and aesthetic characteristics, and reducing the energy costs of cooling buildings. Urban green spaces also can provide ecosystem services in which the recreation and relaxation facilities are especially available to urban dwellers and tourists too. To confirm the multiple roles played by green spaces, certain level of qualitative improvements and distribution of green spaces within the urban area should be considered and incorporated effectively into the environmental sustainability agenda. To do this, an integrated approach regarding the planning, monitoring, designing and maintaining of urban green spaces is required for improving the environmental sustainability in cities in different countries.

Based on the Characteristics of Respondents and the Voice of the Urban Neighborhood Public Space Business Facilities Noise Environment Evaluation Research

Comfort is one of the important indicators evaluation of voice. In order to understand the urban neighborhood public space environment of comfort,this paper is to explore characteristics of consumer society on the public space environment evaluation of the effect,and using the questionnaire survey method,to evaluate the Harbin city neighborhood area public space as the typical case analysis. Based on one of the main sound source in neighborhood public space,environment,business facilities environment as the breakthrough point,it is to consider neighborhood public space environment evaluation and social characteristics.

Space luminous environment adaptability of missile-borne star sensor

To solve the problem of stray interference to star point target identification while a star sensor imaging to the sky, a study on space luminous environment adaptability of missile-borne star sensor was carried out. By Plank blackbody radiation law and some astronomic knowledge, irradiancies of the stray at the star sensor working height were estimated. By relative astrophysical and mathematics knowledge, included angles between the star sensor optical axis point and the stray at any moment were calculated. The calculation correctness was verified with the star map software of Stellarium. By combining the upper analysis with the baffle suppression effect, a real-time model for space luminous environment of missile-borne star sensor was proposed. By signal-noise rate （SNR） criterion, the adaptability of missile-borne star sensor to space luminous environment was studied. As an example, a certain type of star sensor was considered when imaging to the starry sky on June 22, 2011 （the Summer Solstice） and September 20, 2011 （August 23 of the lunar year, last quarter moon） in Beijing. The space luminous environment and the adaptability to it were simulated and analyzed at the star sensor working height. In each period of time, the stray suppression of the baffle is analyzed by comparing the calculated included angle between the star sensor optical axis point and the stray with the shielded provided by system index. When the included angle is larger than the shielded angle and less than 90~, the stray is restrained by the baffle. The stray effect on star point target identification is analyzed by comparing the irradiancy of 6 magnitude star with that of the stray on star sensor sensitization surface. When the irradiancy of 6 magnitude star is 5 times more than that of the stray, there is no effect on the star point target identification. The simulation results are identicat with the actual situation. The space luminous environment of the missile-borne star sensor can be estimated real-timely by this model. The adaptability of the star sensor to space luminous environment can be analyzed conveniently. A basis for determining the relative star sensor indexes, the navigation star chosen strategy and the missile launch window can be provided.

The Space Environment Monitors of Shenzhou Manned Spacecrafts

For the purpose of ensuring normal operations of Shenzhou (SZ) series of manned spacecrafts and cosmonauts' safety, Space Environment Monitors (SEM)are mounted on board SZ-2, 3, 4, 5. SEMs aim to detect the high energy particles, the low energy particles, charging potential, atmospheric desity and composition. Detection of SEMs enable us to understand better the space environment in the manned spacecraft's orbit, and to provide a good space environment services for the spacecraft and cosmonauts. In addition, by using the data from SEMs, we have achieved some scientific accomplishments, such as the energy spectra of precipitating electrons, the abnormal variety of atmospheric density and composition during geomagnetic disturbances, the electron angle distribution in the low orbit and so on.

A planetary perspective on Earth's space environment evolution

The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior process is contentious. In the past several decades,space weather and space climate have been extensively studied based on either observation data measured directly by man-made instruments or ancient data inferred indirectly from some historical medium of past thousands of years. The acquired knowledge greatly helps us to understand the dynamic processes in the space environment of modern Earth, which has a strong magnetic dipole and an oxygen-rich atmosphere. However, no data is available for ancient space weather and climate(>5 ka). Here, we propose to take the advantage of " space-diversity" to build a " generalized planetary space family", to reconcile the ancient space environment evolution of planet Earth from modern observations of other planets in our solar system. Such a method could also in turn give us a valuable insight into other planets' evolution.

ON MARKOV CHAINS IN SPACE-TIME RANDOM ENVIRONMENTS

In Section 1, the authors establish the models of two kinds of Markov chains in space-time random environments (MCSTRE and MCSTRE(+)) with abstract state space. In Section 2, the authors construct a MCSTRE and a MCSTRE(+) by an initial distribution Φ and a random Markov kernel (RMK) p(γ). In Section 3, the authors es-tablish several equivalence theorems on MCSTRE and MCSTRE(+). Finally, the authors give two very important examples of MCMSTRE, the random walk in spce-time random environment and the Markov br...

Sustainable living neighbourhoods:Measuring public space quality and walking environment in Lisbon

Obesity and global warming are two major challengesthat affect communities’health and quality of life.Providing good walking environments,with appropriate pedestrian infrastructure,green areas and access to commercial retail and transport hubs favour liveable,healthy,and sustainable cities.The Lisbon City Hall has implemented an intervention program in the public space as a strategy to improve environmental quality and mitigate the effects of climate change.The program“A square in each neighbourhood”intends not only to reinforce the economic base of Lisbon,namely tourism,restaurants,commerce,and creative activities but also to promote physical activity and improve the quality of living of all citizens.For studying the impact of the public space quality on the walking environment,Campolide,a typical Lisbon neighbourhood,Portugal,which includes one of the requalified squares,was selected.A two-step methodology based on spatial modelling is proposed.In the first step,the public space quality was evaluated based on a set of 13 urban quality attributes.Attributes,intended for the street level,were collected from open data platforms and complemented with a field survey.Then,through spatial analysis,these attributes were used to build the Pedestrian Environment Quality Indicator and the Priority Intervention Indicator.Using these indicators,walking-friendly streets were mapped and the most critical sites that require priority intervention were identified to prepare for the requalification planning process.The street with the highest quality in the study area according to the dimensions evaluated-connectivity,convenience,comfort,cleanliness,and conviviality-has a great offer of trees,bus stops,commercial establishments,commercial diversity,crossings,paper bins/eco points and esplanades.On the opposite side of the rank,the street with the lowest quality has no trees or green areas,transport stops,benches and tables,or commercial activity.The urban quality indicators constitute a helpful tool for city planners and policymakers when planning sustainable living neighbourhoods.

YingHuo-1——Martian Space Environment Exploration Orbiter

This paper gives a brief introduction of YingHuo-1(YH-1),a Chinese Martian Space Environment Exploration Orbiter.YH-1 is a micro-satellite developed by Chinese Aerospace Industry,and will be launched together with Russian spacecraft,Phobos-Grunt,to orbit Mars in September,2009.Four payloads are selected for the mission,plasma package,including of electron analyzer,ion energy and mass analyzer;sat-sat occultation receiver;flux-gate magnetometer;and optical monitor.YH-1 mission focus on the investigation of the characteristics and its evolution of the Martian space Environment,and identifying major plasma processes,which provide channels for Martian volatiles escaping.

A Hygienic Survey of the Environment of Underground Space and Buildings

Full utilization of underground space and buildings could have positive economic and social effects. However, the microclimate and air quality must be well controlled so that they are not harmful to human health. This survey indicated that relative humidity is a common hygienic problem in underground space and buildings. Attention should be paid to humidity control and to the strengthening of routine ventilation at the construction stage. Carbon dioxide can be used as a hygiene index of air pollution; the sanitary standard for it in the air of underground buildings is 10%. The hygienic survey shows that the concentration of carbon dioxide is usually below this standard in the environments of underground space and buildings. (c)1989 Academic Press,Inc.

Model of Markov Chains in Space-Time Random Environments

A general framework of stochastic model for a Markov chain in a space-time random environment is introduced, here the environment ξ^＊：={ξ1,x∈N,x∈ X}is a random field. We study the dependence relations between the environment and the original chain, especially the ＂feedback＂. Some equivalence theorems and law of large numbers are obtained.

SPACE ENVIRONMENT RESEARCH IN CHINA

In this paper, China’s research work on space environment and its new development was introduced, which covered space environment probing especially satellite survey, collection and study of space environment data and models,space environment forecasting and effects of space environment on spacecraft as well.

Space Environment Deteation of Chinese Meteorological Satellites

This paper presents the space environment detection of Chinese geosynchronous and sun-synchronous meteorological satellites and gives a short perspective of space environment observations on board meteorological satellites.

Actual Measurement of the Microclimate Environment of Green Spaces and Dynamic Simulation of Building Height in Xijing Community of Beijing

In this paper, three types of green spaces in Xijing Community in Shijingshan District of Beijing were selected for as the measuring points, the HOBO portable weather station was used to monitor the microclimate environmental changes in the same period and summarize the data of microclimate factors. The effectiveness of the simulation was verified by comparing the measured data with the simulated data obtained through ENVI-met. And strategies for microclimate adaptive design in residential areas were proposed according to the microclimate environmental characteristics of several green spaces.

Analysis of the Impact of Large Constellations on the Space Debris Environment and Countermeasures

Large constellations have developed rapidly in recent years because of their unique advantages, but they will inevitably have a major negative impact on the space debris environment, leading to its deterioration. The key to mitigate the impact is the success rate and duration of the post-mission disposal(PMD) process. Aiming at solving this problem, this paper further studies the impact of large constellations on other space assets under different PMD strategies through simulation, and proposes corresponding strategies and suggestions for mitigation.According to One Web’s large constellation launch plan, the dangerous intersection of the large constellation with existing space assets at different stages of the constellations life cycle is calculated by simulation. Based on this, the influence of the large constellation operation on existing space assets at different times and strategies of PMD is analyzed. The conclusion shows that in the PMD stage, large constellations have the greatest impact on existing space assets;the PMD duration and number of satellites performing PMD at the same time are key factors to the degree of negative impact. The faster the PMD is, the less threat it poses to other spacecraft. More results and conclusions are still being analyzed.

Development of Space Environment Research in China

Abstract This paper presents the recent research progress on space environment in China. The space environment here includes space environment models, forecast methodology and space environment effects on spacecrafts. Finally the development trends of China's space environment research are discussed.