Cell-free hemoglobin and hemin catalyzing triclosan oxidative coupling in plasma: A novel exogenous phenolic pollutants coupling pathway.

Previous studies reported that hemoprotein CYP450 catalyzed triclosan coupling is an "uncommon" metabolic pathway that may enhance toxicity, raising concerns about its environmental and health impacts. Hemoglobin, a notable hemoprotein, can catalyze endogenous phenolic amino acid tyrosine coupling reactions. Our study explored the feasibility of these coupling reactions for exogenous phenolic pollutants in plasma. Both hemoglobin and hemin were found to catalyze triclosan coupling in the presence of H2O2. This resulted in the formation of five diTCS-2 H, two diTCS-Cl-3 H, and twelve triTCS-4 H in phosphate buffer, with a total of nineteen triclosan coupling products monitored using LC-QTOF. In plasma, five diTCS-2 H, two diTCS-Cl-3 H, and two triTCS-4 H were detected in hemoglobin-catalyzed reactions. Hemin showed a weaker catalytic effect on triclosan transformation compared to hemoglobin, likely due to hemin dimerization and oxidative degradation by H2O2, which limits its catalytic efficiency. Triclosan transformation in the human plasma-like medium still occurs with high H2O2, despite the presence of antioxidant proteins that typically inhibit such transformations. In plasma, free H2O2 was depleted within 40 minutes when 800 µM H2O2 was added, suggesting a rapid consumption of H2O2 in these reactions. Antioxidative species, or hemoglobin/hemin scavengers such as bovine serum albumin, may inhibit but not completely terminate the triclosan coupling reactions. Previous studies reported that diTCS-2 H showed higher hydrophobicity and greater endocrine-disrupting effects compared to triclosan, which further underscores the potential health risks. This study indicates that hemoglobin and heme in human plasma might significantly contribute to phenolic coupling reactions, potentially increasing health risks.

MouseNet: A biologically constrained convolutional neural network model for the mouse visual cortex.

Convolutional neural networks trained on object recognition derive inspiration from the neural architecture of the visual system in mammals, and have been used as models of the feedforward computation performed in the primate ventral stream. In contrast to the deep hierarchical organization of primates, the visual system of the mouse has a shallower arrangement. Since mice and primates are both capable of visually guided behavior, this raises questions about the role of architecture in neural computation. In this work, we introduce a novel framework for building a biologically constrained convolutional neural network model of the mouse visual cortex. The architecture and structural parameters of the network are derived from experimental measurements, specifically the 100-micrometer resolution interareal connectome, the estimates of numbers of neurons in each area and cortical layer, and the statistics of connections between cortical layers. This network is constructed to support detailed task-optimized models of mouse visual cortex, with neural populations that can be compared to specific corresponding populations in the mouse brain. Using a well-studied image classification task as our working example, we demonstrate the computational capability of this mouse-sized network. Given its relatively small size, MouseNet achieves roughly 2/3rds the performance level on ImageNet as VGG16. In combination with the large scale Allen Brain Observatory Visual Coding dataset, we use representational similarity analysis to quantify the extent to which MouseNet recapitulates the neural representation in mouse visual cortex. Importantly, we provide evidence that optimizing for task performance does not improve similarity to the corresponding biological system beyond a certain point. We demonstrate that the distributions of some physiological quantities are closer to the observed distributions in the mouse brain after task training. We encourage the use of the MouseNet architecture by making the code freely available.

A Novel Analytical Model for the IEEE 802.11p/bd Medium Access Control, with Consideration of the Capture Effect in the Internet of Vehicles.

The traditional vehicular ad hoc network (VANET), which is evolving into the internet of vehicles (IoV), has drawn great attention for its enormous potential in road safety improvement, traffic management, infotainment service support, and even autonomous driving. IEEE 802.11p, as the vital standard for wireless access in vehicular environments, has been released for more than one decade and its evolution, IEEE 802.11bd, has also been released for a few months. Since the analytical models for the IEEE 802.11p/bd medium access control (MAC) play important roles in terms of performance evaluation and MAC protocol optimization, a lot of analytical models have been proposed. However, the existing analytical models are still not accurate as a result of ignoring some important factors of the MAC itself and real communication scenarios. Motivated by this, a novel analytical model is proposed, based on a novel two-dimensional (2-D) Markov chain model. In contrast to the existing studies, all the important factors are considered in this proposed model, such as the backoff freezing mechanism, retry limit, post-backoff states, differentiated packet arrival probabilities for empty buffer queue, and queue model of packets in the buffer. In addition, the influence of the capture effect under a Nakagami-m fading channel has also been considered. Then, the expressions of successful transmission, collided transmission, normalized unsaturated throughput, and average packet delay are all meticulously derived, respectively. At last, the accuracy of the proposed analytical model is verified via the simulation results, which show that it is more accurate than the existing analytical models.

Assessment of heavy metal contamination of an electrolytic manganese metal industrial estate in northern China from an integrated chemical and magnetic investigation.

Heavy metal concentrations (Al, V, Mn, Fe, Co, Ni, Cu, Zn, and Pb) and the magnetic properties of soil and sediment samples in/around an electrolytic manganese metal (EMM) industrial estate in northern China were investigated. Potential enrichment of Mn, Zn, and Pb was found in/around the core area of the EMM industrial estate; however, the pollution load index (PLI) values did not indicate severely polluted levels. For adults, all hazard index (HI) values of noncarcinogenic risks in the soil samples were below the safe level of 1.00. For children, none of the HI values exceeded the safe level, except Mn (HI = 1.23) in one industrial estate sample. The particle size of magnetic materials was mostly in the range of stable single-domain, and coarser ferrimagnetic phases enhanced the magnetic parameters in the industrial estate soils. Highly positive correlations were found between magnetic parameters, heavy metal concentrations, and PLI values, demonstrating that the magnetic parameters are an efficient proxy for assessing heavy metal contamination. Enrichment of Mn, Zn, and Pb was mainly derived from the EMM industry. The data showed that the EMM industrial estate under cleaner production had limited adverse impacts on the adjacent environment from the perspective of heavy metal contamination.

Performance Analysis of IEEE 802.11p MAC with Considering Capture Effect under Nakagami-m Fading Channel in VANETs.

Vehicular ad hoc networks (VANETs) have recently drawn a large amount of attention because of their enormous potential in road safety improvement and traffic management as well as infotainment service support. As the standard of medium access control (MAC) and physical (PHY) layers for VANETs, IEEE 802.11p has been proposed for more than a decade. Though performance analyses of IEEE 802.11p MAC have been performed, the existing analytical methods still need to be improved. In this paper, to assess the saturated throughput and the average packet delay of IEEE 802.11p MAC in VANETs, a two-dimensional (2-D) Markov model is introduced by considering the capture effect under Nakagami-m fading channel. Moreover, the closed-form expressions of successful transmission, collided transmission, saturated throughput, and average packet delay are carefully derived. Finally, the simulation results are demonstrated to verify the accuracy of the proposed analytical model, which also proves that this analytical model is more precise than the existing ones in terms of saturated throughput and average packet delay.

Tiered ecological risk assessment of nonylphenol and tetrabromobisphenol A in the surface waters of China based on the augmented species sensitivity distribution models.

The ecological risks of nonylphenol (NP) and tetrabromobisphenol A (TBBPA) have received continued attention owing to their large consumption, frequently detection, adverse effects on the reproductive fitness, and lack of risk assessment technical systems. The geometric mean of the median concentrations of NP in the 22 surface waters was 0.278 µg/L, and TBBPA in the seven surface waters was 0.014 µg/L in China. The species sensitivity distribution (SSD) models were augmented by extrapolated reproductive toxicity data of native species to reduce uncertainty. The SSD models and the hazardous concentrations for 5% of species exhibited good robustness and reliability using the bootstrap method and minimum sample size determination. The acute and reproductive predicted no-effect concentrations (PNECs) were derived as 9.88 and 0.187 µg/L for NP, and 56.6 and 0.0878 µg/L for TBBPA, respectively. The risk quotients indicated that 11 of 22 locations for NP, and 3 of 7 locations for TBBPA were at high ecological risk levels based on the reproductive PNECs. Furthermore, the higher tier ecological risk assessment (ERA) based on potential affected fraction and joint probability curves indicated that the ecological risks in the four of above locations needed further concern. The ERA based on both the acute and reproductive toxicity is essential for assessing the ecological risks of NP and TBBPA, otherwise using acute PNECs only may result in an underestimation of ecological risk. The developed tiered ERA method and its framework can provide accurate, detailed, quantitative, locally applicable, and economically technical support for ERA of typical endocrine-disrupting chemicals in China.

A tiered probabilistic approach to assess antibiotic ecological and resistance development risks in the fresh surface waters of China.

Exposure to antibiotics can result in not only ecotoxicity on aquatic organisms but also the development of antibiotic resistance. In the study, the ecotoxicity data and minimum inhibitory concentrations of the antibiotics were screened to derive predicted no-effect concentrations of ecological (PNECeco) and resistance development risks (PNECres) for 36 antibiotics in fresh surface waters of China. The derived PNECeco and PNECres values were ranged from 0.00175 to 2351 µg/L and 0.037-50 µg/L, respectively. Antibiotic ecological and resistance development risks were geographically widespread, especially in the Yongding River, Daqing River, and Ziya River basins of China. Based on the risk quotients, 11 and 14 of 36 target antibiotics were at high ecological risks and high resistance development risks in at least one basin, respectively. The higher tiered assessments provided more detailed risk descriptions by probability values and ß-lactams (penicillin and amoxicillin) were present at the highest levels for ecological and resistance development risks. Although there was uncertainty based on the limited data and existing methods, this study can indicate the overall situation of the existing risk levels and provide essential insights and data supporting antibiotic management.

Occurrence and emission of phthalates, bisphenol A, and oestrogenic compounds in concentrated animal feeding operations in Southern China.

Phthalates (PAEs), bisphenol A (BPA), and oestrogenic compounds have become major concerns due to their endocrine-disrupting effect. However, few studies related to the occurrence of PAEs, BPA, and oestrogen in food and compost from different growth age livestock have been conducted. In this study, faeces, urine and food samples were collected from a typical livestock (cow) and a special livestock (pigeon) from concentrated animal feeding operations (CAFOs). The daily total oestrogen excretion of a single cow ranged from 192 µg/day to 671 µg/day, which was significantly higher than that of a single pigeon (0-0.01 µg/day). Conjugated oestrogens represented 22.0-46.0% of the total oestrogens excreted from cow faeces and 80.7-91.8% of those from cow urine, indicating that the form of the excreted oestrogens depends on the livestock species and type of excrement. BPA was all detected in all livestock manure and food, and the concentration in pigeon was 9.2-40.2 ng/g and 23.1 ng/g respectively, while that in cattle was 50.5-72.0 ng/g and 41.1 ng/g respectively. The results indicated that the food is significant sources of BPA entering the process of cow and pigeon breeding. Diethyl phthalate (DEP) was detected at high frequency in pigeon faeces samples, suggesting that pigeons were highly exposed to these plasticisers. The total oestradiol equivalent quantity (EEQt) of livestock origin in aquatic environments was estimated to be 2.99 ng/L, which was higher than the baseline hazard value (1 ng/L) (Xu et al., 2018). The study provides data on the emissions and sources of PAEs, BPA, and oestrogenic compounds from different livestock in CAFOs and demonstrates that food is a significant source of BPA entering livestock.

A QSAR-ICE-SSD Model Prediction of the PNECs for Per- and Polyfluoroalkyl Substances and Their Ecological Risks in an Area of Electroplating Factories.

Per- and polyfluoroalkyl substances (PFASs) are a class of highly fluorinated aliphatic compounds that are persistent and bioaccumulate, posing a potential threat to the aquatic environment. The electroplating industry is considered to be an important source of PFASs. Due to emerging PFASs and many alternatives, the acute toxicity data for PFASs and their alternatives are relatively limited. In this study, a QSAR-ICE-SSD composite model was constructed by combining quantitative structure-activity relationship (QSAR), interspecies correlation estimation (ICE), and species sensitivity distribution (SSD) models in order to obtain the predicted no-effect concentrations (PNECs) of selected PFASs. The PNECs for the selected PFASs ranged from 0.254 to 6.27 mg/L. The ΣPFAS concentrations ranged from 177 to 983 ng/L in a river close to an electroplating industry in Shenzhen. The ecological risks associated with PFASs in the river were below 2.97 × 10-4.

Diel pattern in the structure and function of the gut microbial community in Lymantria dispar asiatica (Lepidoptera: Lymantriidae) larvae.

In the present study, diel pattern in gut microbial communities in insects were evaluated. Lymantria dispar asiatica fourth instar larvae (72 ± 2 hr after molting) at noon (LdD) and midnight (LdN) were used for a comparative analysis of the gut microbial community. Ten bacterial operational taxonomic units (OTUs) were shared between LdD and LdN samples. One bacterial OTU was specific to LdD. The dominant gut microbes were OTU72 in LdD and OTU75 in LdN. A linear discriminant analysis effect size cladogram suggested that ten bacterial OTUs maintain significant differences in relative abundances between LdD and LdN. These results agreed with the discrete ellipses between LdD and LdN in principal coordinates analysis plots. Additionally, using phylogenetic investigation of communities by reconstruction of unobserved states, the gut microbial community was assigned to 23 functional terms, among which 22 exhibited significant differences between LdD and LdN. To conclude, the present study documented a diel pattern in the gut microbial community of L. dispar asiatica larvae.

Variation in the pH of experimental diets affects the performance of Lymantria dispar asiatica larvae and its gut microbiota.

To study dietary pH effects on Lymantria dispar asiatica larvae and provide a theoretical basis for its control in different forests, phosphate buffers (PBs) of pH 6, 7, and 8 were used to prepare experimental diets. The diet prepared with pH 6 PB was named as DPB6, with pH 8 PB as DPB8, and with pH 7 PB as DPB7 (control). The dietary pH was 5.00 in DPB6, 6.05 in control, and 6.50 in DPB8. After feeding on the diets with different pH values for 84 hr, fourth-instar caterpillars were randomly collected. Growth and various physiological traits were determined and 16S recombinant DNA sequencing was performed using the intestinal microflora of surviving larvae. Results showed that the mortality was 30% in DPB6, and 10% in DPB8, while no mortality was observed in control. The partial least squares discriminant analyses suggested that diets prepared with PB of different pH resulted in different food intake, amount of produced feces, weight gain, digestive enzyme activities, and antioxidant enzyme activities in larvae. Interestingly, both the highest weight gain and the lowest total antioxidant capacities were seen in control larvae. Results also showed that the larval gut microbiota community structure was significantly affected by dietary pH. Moreover, linear discriminant analysis effect size suggested that the family Acetobacteraceae in control, genus Prevotella in DPB8, and genus Lactococcus, family Flavobacteriaceae, family Mitochondria, and family Burkholderiaceae in DPB6 contributed to the diversity of the larval gut microbial community.

Avermectin stress varied structure and function of gut microbial community in Lymantria dispar asiatica (Lepidoptera: Lymantriidae) larvae.

Lymantria dispar asiatica is a globally distributed herbivorous pest. Avermectin is a highly effective, broad-spectrum insecticide. In this study, fourth instar L. dispar asiatica larvae were exposed to a LC30 dose of avermectin. The structure and function of larval gut microbial community was analyzed to examine how gut microbiota in L. dispar asiatica larvae responded to avermectin stress. Results showed that the structure and function of gut microbial community in L. dispar asiatica larvae were varied by avermectin stress. To be precise, more than half quantity of the observed Optical Taxonomic Units (OTUs) showed significantly different abundances under avermectin stress. Linear discriminant analysis effect size (LEfSe) suggested nine bacterial genera and 12 fungal genera contributed to the different gut microbial community structure in L. dispar asiatica larvae. Gut microbial function classification (PICRUSt and FUNGuild) suggested that three bacterial function categories and a fungal function guild were significantly increased, and two fungal function guilds were significantly decreased by avermectin stress. This study furthers our understanding of the physiology of L. dispar asiatica larvae under avermectin stress, and is an essential step towards future development of potential pesticide targets.

A Stackelberg Game-Based Caching Incentive Scheme for Roadside Units in VANETs.

As a key technology of intelligent transportation systems (ITS), vehicular ad hoc networks (VANETs) have been promising to provide safety and infotainment for drivers and passengers. To support different applications about traffic safety, traffic efficiency, autonomous driving and entertainment, it is important to investigate how to effectively deliver content in VANETs. Since it takes resources such as bandwidth and power for base stations (BSs) or roadside units (RSUs) to deliver content, the optimal pricing strategy for BSs and the optimal caching incentive scheme for RSUs need to be studied. In this paper, a framework of content delivery is proposed first, where each moving vehicle can obtain small-volume content files from either the nearest BS or the nearest RSU according to the competition among them. Then, the profit models for both BSs and RSUs are established based on stochastic geometry and point processes theory. Next, a caching incentive scheme for RSUs based on Stackelberg game is proposed, where both competition sides (i.e., BSs and RSUs) can maximize their own profits. Besides, a backward introduction method is introduced to solve the Stackelberg equilibrium. Finally, the simulation results demonstrate that BSs can obtain their own optimal pricing strategy for maximizing the profit as well as RSUs can obtain the optimal caching scheme with the maximum profit during the content delivery.

Sediment information on natural and anthropogenic-induced change of connected water systems in Chagan Lake, North China.

This study discusses changes in connected water systems in Chagan Lake induced by the interference of natural and human activities, based on the analysis of sediment characteristics. In this study, the following sediment characteristics were investigated in the lake area, the natural supply area, and the lake drainage area: mineral composition; particle size distribution; magnetic susceptibility; nutrient content; content of isotopes δ13Corg and δ15N; and content of heavy metals and of metallic oxides. The results showed that silicate minerals quartz, orthoclase, and anorthose were abundant in the whole lake water system. Quartz accumulated more easily in the lake area, while carbonate masses in the lake mainly came from the Huolinhe River. Moving from the lake area to the water diversion and drainage areas, fine particles clearly decreased, while coarse particles significantly increased due to the increase in hydraulic erosion. The main sources of nutrients and of organic matter are: the residual of the drainage from the Qianguo irrigated areas; the surrounding villages and the tourist area; and the decomposition of aquatic organisms. A large number of anthropogenic heavy metals, such as Hg, Cu, and As, were accumulated in the artificial water diversion area and in the farmland drainage area. This study indicates that recovering the original connected water system during the wet season, while at the same time enhancing water supply during the dry season could improve the ecological quality of Chagan Lake.

The characteristics of oestrone mobility in water and soil by the addition of Ca-biochar and Fe-Mn-biochar derived from Litchi chinensis Sonn.

In this study, the effect of biochar (BC) derived from Litchi chinensis Sonn. and its modification, including Ca-biochar (Ca-BC) and Fe-Mn-biochar (Fe-Mn-BC), on the transportation of oestrone (E1) in water and soil was investigated. Fe-Mn-BC showed better adsorption ability than other types of biochar (BC, Ca-BC) under different conditions (humic acid, pH, ionic strength) in an aqueous environment. The maximum mass of sorbent at 298 K increased from 1.12 mg g-1 (BC) to 4.18 mg g-1 (Fe-Mn-BC). Humic acid had a greater impact on aqueous E1 adsorption on these biochars than did the pH and ionic strength. Fe-Mn-BC as a soil amendment had a great control of E1 transport in soil, and no leachate of E1 was observed in the column experiment. E1 mobility showed strong retardation in amended soil with Ca-BC (Rf = 11.2) compared with raw soil (Rf = 7.1). These results suggested that Fe-Mn-BC was more effective in controlling E1 transportation, and Fe-Mn-BC could be used as an alternative and inexpensive adsorbent to reduce E1 contaminants from water and soil.

Effect of corn straw biochar application to sediments on the adsorption of 17α-ethinyl estradiol and perfluorooctane sulfonate at sediment-water interface.

The immobilization of organic contaminants in sediment-water systems is of growing concern. Using biochar as sorbent amendment to reduce the mobility of pollutants in the sediment-water interface is becoming increasingly popular as a low-cost and environmentally friendly option. In this study, we mixed sediment from the Weishan Lake with biochar (0%, 2%, and 5% (w/w)) derived from corn straw to investigate the adsorption of perfluorooctane sulfonate (PFOS) and 17α-ethinyl estradiol (EE2). Biochar addition significantly improved the adsorption rates and capacities of EE2 and PFOS on sediments by the factors 1.7-3.5; the organic carbon concentration in the sediment was the main factor influencing this process. The sorption of EE2 and PFOS to sediment was near-linear (Freundlich exponent 1/n of 0.799-0.805), but non-linear for biochar (0.430-0.476) and sediment+biochar (0.370-0.421). The mobility of PFOS in the water-sediment system after biochar addition was significantly reduced, with a considerable increase (about three times) in the sediment-water distribution coefficient Kd. Compared to EE2, PFOS is anionic compound and contains hydrophobic C-F chains and hydrophilic S-O groups, making it more susceptible pH influences and resulting in interactions with-OH, -C=O, Si-O-Si, -O-Si, and -Al-O-Al groups via hydrogen bonding, ligand exchange, and surface complexation. We suggest that biochar amendment at ～5% is a viable approach to immobilize EE2 and PFOS at the sediment-water interface.

Occupational exposure characteristics and health risk of PBDEs at different domestic e-waste recycling workshops in China.

Polybrominated diphenyl ethers (PBDEs) contained in electronic waste (e-waste) can be released to indoor environments and cause occupational health hazards during the recycling process. TVs, washing machines, refrigerators and printed wiring boar (PWB) represent the main domestic e-wastes. In this study, concentrations of Σ7PBDEs in air and dust samples from recycling workshops handling these four major types of e-wastes were measured, and the occupational exposure risk for workers at the corresponding workshops was evaluated. Concentrations of Σ7PBDEs in air and dust were within the ranges of 55.28-369.66 ng/m3 and 158.07-669.81 µg/g, respectively. The highest concentration of Σ7PBDEs in air was detected in the TV recycling workshop, while the refrigerator recycling workshop had the highest level of Σ7PBDEs in dust. The workers at these two e-waste recycling workshops were the most substantially exposed to BDE-209, which accounted for more than 85% of Σ7PBDEs in both air and dust. Compared to other e-waste recycling workshops, the workers at the PWB recycling workshop were also more exposed to BDE-47 and BDE-99. Occupational exposure levels for inhalation and dust ingestion were within the ranges of 3939 pg/kg/d to 26,271 pg/kg/d and 104,945 pg/kg/d to 444,694 pg/kg/d, respectively. The hazard quotient (HQ) values were calculated based on the RfDs provided by the EPA. Total HQ levels of inhalation exposure and dust ingestion were less than 0.222. The results of the HQ indicated that no adverse health effects were expected for workers in these workshops; however, the exposure risk of workers in the PWB recycling workshop (HQ=0.222) was higher than that in other e-waste recycling workshops (HQ=0.022-0.072). At the PWB recycling workshop, BDE-47 and BDE-99 caused the main occupational exposure risk to the workers, while s in the recycling plants handling other types of domestic e-waste BDE-209 was the major contributor to the risk faced by the workers.

Explicit Content Caching at Mobile Edge Networks with Cross-Layer Sensing.

The deployment density and computational power of small base stations (BSs) are expected to increase significantly in the next generation mobile communication networks. These BSs form the mobile edge network, which is a pervasive and distributed infrastructure that can empower a variety of edge/fog computing applications. This paper proposes a novel edge-computing application called explicit caching, which stores selective contents at BSs and exposes such contents to local users for interactive browsing and download. We formulate the explicit caching problem as a joint content recommendation, caching, and delivery problem, which aims to maximize the expected user quality-of-experience (QoE) with varying degrees of cross-layer sensing capability. Optimal and effective heuristic algorithms are presented to solve the problem. The theoretical performance bounds of the explicit caching system are derived in simplified scenarios. The impacts of cache storage space, BS backhaul capacity, cross-layer information, and user mobility on the system performance are simulated and discussed in realistic scenarios. Results suggest that, compared with conventional implicit caching schemes, explicit caching can better exploit the mobile edge network infrastructure for personalized content dissemination.

An INS/WiFi Indoor Localization System Based on the Weighted Least Squares.

For smartphone indoor localization, an INS/WiFi hybrid localization system is proposed in this paper. Acceleration and angular velocity are used to estimate step lengths and headings. The problem with INS is that positioning errors grow with time. Using radio signal strength as a fingerprint is a widely used technology. The main problem with fingerprint matching is mismatching due to noise. Taking into account the different shortcomings and advantages, inertial sensors and WiFi from smartphones are integrated into indoor positioning. For a hybrid localization system, pre-processing techniques are used to enhance the WiFi signal quality. An inertial navigation system limits the range of WiFi matching. A Multi-dimensional Dynamic Time Warping (MDTW) is proposed to calculate the distance between the measured signals and the fingerprint in the database. A MDTW-based weighted least squares (WLS) is proposed for fusing multiple fingerprint localization results to improve positioning accuracy and robustness. Using four modes (calling, dangling, handheld and pocket), we carried out walking experiments in a corridor, a study room and a library stack room. Experimental results show that average localization accuracy for the hybrid system is about 2.03 m.

Joint Content Recommendation and Delivery in Mobile Wireless Networks with Outage Management.

Personalized content retrieval service has become a major information service that consumes a large portion of mobile Internet traffic. Joint content recommendation and delivery is a promising design philosophy that could effectively improve the overall user experience with personalized content retrieval services. Existing research mostly focused on a push-type design paradigm called proactive caching, which, however, has multiple inherent drawbacks such as high device cost and low energy efficiency. This paper proposes a novel, interactive joint content recommendation and delivery system as an alternative to overcome the drawbacks of proactive caching systems. We present several optimal and heuristic algorithms for the proposed system and analyze the system performance in terms of user interest and transmission outage probability. Some theoretical performance bounds of the system are also derived. The effectiveness of the proposed system and algorithms is validated by simulation results.