A Resoure Allocation Framework for Network Slicing with Multi-service Coexistence

Network slicing has been widely recognized as the architectural technology for 5G and beyond wireless network systems to provide tailored service for diverse applications by flexibly splitting and allocating various heterogeneous resources. However, it is still challenging to meet the strict delay requirements of a large number of delay-sensitive applications under traditional slicing architectures. One potential way to tackle this issue is to build network slicing upon Mobile Edge Computing (MEC) systems, where both communication and computing resources are integrated for providing customized service. As such, in this paper, we propose a framework, to jointly optimize communication and computing resources under the scenario of multi-service coexistence, with the objective to minimize the system cost while meeting the diverse QoS requirements. To make the original optimization problem more tractable, we decompose it into two convex sub-problems first. Then we obtain the optimal solutions of the two sub-problems respectively, and finally derive the optimal communication and computing resource allocation scheme based on the optimal solutions of these two sub-problems. Simulation results show that our proposed scheme significantly saves the system cost under various scenarios compared with other benchmarks

On-Wafer Measurement of a Silicon-Based CMOS VCO at 324 GHz

The world s first silicon-based complementary metal oxide/semiconductor (CMOS) integrated-circuit voltage-controlled oscillator (VCO) operating in a frequency range around 324 GHz has been built and tested. Concomitantly, equipment for measuring the performance of this oscillator has been built and tested. These accomplishments are intermediate steps in a continuing effort to develop low-power-consumption, low-phase-noise, electronically tunable signal generators as local oscillators for heterodyne receivers in submillimeter-wavelength (frequency > 300 GHz) scientific instruments and imaging systems. Submillimeter-wavelength imaging systems are of special interest for military and law-enforcement use because they could, potentially, be used to detect weapons hidden behind clothing and other opaque dielectric materials. In comparison with prior submillimeter- wavelength signal generators, CMOS VCOs offer significant potential advantages, including great reductions in power consumption, mass, size, and complexity. In addition, there is potential for on-chip integration of CMOS VCOs with other CMOS integrated circuitry, including phase-lock loops, analog- to-digital converters, and advanced microprocessors

Power-spectrum trading for full-duplex D2D communications in cellular networks

Device-to-device (D2D) communications allows two adjacent mobile terminals transmit signal directly without going through base stations, which has been considered as one of the key technologies for future mobile networks. As full-duplex (FD) communications can improve the performance (i.e., throughput, energy efficiency (EE)) of communications systems, it is commonly used in practical D2D communications scenarios. However, FD-enabled D2D communications also results in self-interference. To fully realize the potential benefits of FD-enabled D2D communications, an effective resource allocation mechanism is critical to avoid not only the self-interference of FD-enabled D2D communications but also the interference between D2D users (DUs) and cellular users (CUs). In this paper, we investigate the resource allocation issue for FD-enabled DUs and traditional CUs. Considering the asymmetry of energy and spectrum resources of DUs and CUs, we propose a power-spectrum trading mechanism to achieve mutual benefits for both types of users. A concave-convex procedure algorithm is employed to solve the optimization problem of power allocation, and then a maximum weighted bipartite matching based method is proposed to select proper D2D pairs to maximize the overall system throughput. Numerical results show that the proposed scheme can remarkably improve the overall throughput and EE of FD-enabled D2D communications system

How Do Differences in Land Ownership Types in China Affect Land Development? A Case from Beijing

China has a unique land use system in which there are two types of land ownership, namely, state-owned urban land and farmer collective-owned rural land. Despite strict restrictions on the use rights of farmer collective-owned land, rural land is, in fact, developed along two pathways: it is formally acquired by the state and transferred into state ownership, or it is informally developed while remaining in collective ownership. Taking Beijing, the capital, as an example, and using data from land use surveys in the Changping district of the city, this paper examines the spatial patterns and characteristics of land development along these two pathways, and sets up a multinomial logit model to test whether land development with and without ownership change was affected by the same factors. The findings suggest that: (1) development on collective-owned land is more spatially scattered, and its links to public infrastructure are weaker; (2) transportation infrastructure, farmer income, spatial location, and previous land usage are the major factors that affect land development; nevertheless, the influences of the factors are different for the two pathways

The Evolving Structure of Rural Construction Land in Urbanizing China: Case Study of Tai’an Prefecture

With a rapid surge in urbanization, rural functions and the structure of rural construction land are undergoing profound change. Using the village-level units of Tai’an Prefecture in the North China Plain as the research object, this study employs the land use survey data in 2019, selecting the diversity index, concentration index, land use type, and location index to analyze the spatial pattern of rural construction land structure. Thereafter, a multiple linear regression model is developed to identify the driving factors of spatial differentiation in rural construction land structure. The results show that (1) there are remarkable spatial differences in all indices representing the structure of construction land in Tai’an and the landscape varies across the indices, and (2) the most important factors affecting the spatial differentiation of construction land use structure are the location, socioeconomic development, and policy, while the effects of natural conditions are limited. The worse the location conditions and the more regressed the economic and social development level, the lower the diversity of construction land and the more unitary the structure. The results of this case study demonstrate the crucial role of the changing urban–rural relation under rapid urbanization in shaping the geography of rural land use, which is expected to have reference significance for researchers and policy makers dealing with rural transformation in developing countries

How Do Differences in Land Ownership Types in China Affect Land Development? A Case from Beijing

China has a unique land use system in which there are two types of land ownership, namely, state-owned urban land and farmer collective-owned rural land. Despite strict restrictions on the use rights of farmer collective-owned land, rural land is, in fact, developed along two pathways: it is formally acquired by the state and transferred into state ownership, or it is informally developed while remaining in collective ownership. Taking Beijing, the capital, as an example, and using data from land use surveys in the Changping district of the city, this paper examines the spatial patterns and characteristics of land development along these two pathways, and sets up a multinomial logit model to test whether land development with and without ownership change was affected by the same factors. The findings suggest that: (1) development on collective-owned land is more spatially scattered, and its links to public infrastructure are weaker; (2) transportation infrastructure, farmer income, spatial location, and previous land usage are the major factors that affect land development; nevertheless, the influences of the factors are different for the two pathways

Evolving population distribution in China's border regions: Spatial differences, driving forces and policy implications.

The security and socioeconomic development of China's border areas are of great significance to the nation and the wider world. Using census, statistical, digital elevation model (DEM) and network data, this paper employs visual analysis to capture population distribution patterns in China's 131 border counties from 1982 to 2010. Multiple stepwise regression is carried out to identify the influencing factors of population dynamics in border regions. The main findings include: China's most heavily populated border areas are primarily in the northeast, northwest, and the Guangxi-Yunnan region, while rapid growth of population is found in western Inner Mongolia, southwest Xinjiang, northwest Tibet, and southern Yunnan. Given the increasingly market-oriented migration mechanism, the national reclamation policy has been no longer effective in population attraction in the new century. Education has significantly lowered and will continuously lower the fertility rate in remote border areas. The factors influencing population growth show a remarkable regional heterogeneity along China's long border

The Spatial Distribution and Influencing Factors of Employment Multipliers in China’s Expanding Cities

In the process of urbanization in developing countries, creating enough jobs to realize the transition from an agricultural population to a non-agricultural population is a major goal of development. The differences and localities of cities need to be considered in the policymaking process. This study estimated the local employment multipliers of expanding cities in China and calculated the employment multiplier of each city. First, there are obvious differences in the size of employment multipliers across cities; therefore, it is necessary to adopt different policies in employment promotion. Second, an inverted-U-shape relationship is detected between employment multiplier and city size, namely the larger the city, the greater the employment multiplier, but when the city size exceeds a certain value, the employment multiplier begins to decline. Third, different degrees of influence are generated by factors for cities at different levels of economic development. Based on the research results, we suggest that expansion of the trade sector be promoted in small- and medium-sized cities, to give full play to its employment multiplier effect; meanwhile, in large cities, the degree of specialization of the trade sector and diversification of the non-trade sector should be improved

The Evolving Structure of Rural Construction Land in Urbanizing China: Case Study of Tai’an Prefecture

With a rapid surge in urbanization, rural functions and the structure of rural construction land are undergoing profound change. Using the village-level units of Tai’an Prefecture in the North China Plain as the research object, this study employs the land use survey data in 2019, selecting the diversity index, concentration index, land use type, and location index to analyze the spatial pattern of rural construction land structure. Thereafter, a multiple linear regression model is developed to identify the driving factors of spatial differentiation in rural construction land structure. The results show that (1) there are remarkable spatial differences in all indices representing the structure of construction land in Tai’an and the landscape varies across the indices, and (2) the most important factors affecting the spatial differentiation of construction land use structure are the location, socioeconomic development, and policy, while the effects of natural conditions are limited. The worse the location conditions and the more regressed the economic and social development level, the lower the diversity of construction land and the more unitary the structure. The results of this case study demonstrate the crucial role of the changing urban–rural relation under rapid urbanization in shaping the geography of rural land use, which is expected to have reference significance for researchers and policy makers dealing with rural transformation in developing countries

A Geographically Weighted Regression Model for Health Improvement: Insights from the Extension of Life Expectancy in China

Health improvement is an important social development goal for every country. By using a geographical weighted regression (GWR) model on the 5th and 6th censuses data, this paper analyzes the spatially varied influencing factors of the change in life expectancy of residents in Chinses cities. The results indicate that: (1) The initial level of life expectancy may have a negative correlation with its increase, indicating that life expectancy in different areas may eventually converge to a higher level; moreover, the degree of convergence of life expectancy in cities with different economic development levels is variant. (2) Results of geographically weighted regression model demonstrate significant spatial heterogeneity in the effects of the level of economic development, medical conditions, demographic structure, and natural environment on health improvement. Natural conditions, such as topography, dictate the change in life expectancy in most cities in the middle eastern region of China. Change of educational level is the leading factor in the vast western region while the change in birth rate is the most critical in Xinjiang. Thus, local-based strategies are critical for solving health problems, especially with a focus on promoting health conditions in middle-income and low-income areas