Automated interpretation and reporting of chest X-rays (CXRs) hold significant promise in reducing diagnostic errors and supporting radiologists under heavy clinical workloads. However, existing methods typically rely on global visual features and token-level supervision, limiting their sensitivity to subtle abnormalities and reducing their clinical reliability. To address these challenges, we present Reflective X-ray Network (RefleXNet), which systematically integrates multi-scale visual feature fusion and anatomical relational reasoning with a targeted self-reflective learning strategy. RefleXNet first constructs multi-scale visual representations and captures anatomical context through graph-based relational modeling. Building upon these representations, we introduce a targeted self-reflection strategy that uses clinically guided feedback from generated reports to selectively refine abnormality predictions and their associated region-level visual features. Extensive experiments on MIMIC-CXR demonstrate that RefleXNet consistently outperforms state-of-the-art baselines across clinical factual correctness metrics. Notably, our compact 3B-parameter model surpasses several recent models with over twice the parameter count. Additionally, RefleXNet exhibits strong generalization performance in zero-shot evaluations on IU-Xray compared with leading multimodal language models, highlighting its robustness and clinical effectiveness.

Automated chest X-ray report generation requires not only clinical accuracy but also transparent and interpretable diagnostic reasoning. In this work, we propose FiR-Rad, a two-stage framework that combines explicit structured reasoning with targeted fine-grained optimization. In the first stage, a supervised chain-of-thought approach guides the model to sequentially analyze and describe a comprehensive range of clinically significant thoracic abnormalities, ensuring clinically meaningful coverage. In the second stage, we introduce a segment-level reinforcement learning strategy based on Group Relative Policy Optimization (GRPO), which assigns precise rewards to each disease-specific reasoning step by evaluating the accuracy of corresponding findings in the synthesized report. This design provides direct feedback for intermediate reasoning and encourages consistency between detailed abnormality analysis and final diagnostic conclusions. Experimental results on the MIMIC-CXR and IU-Xray datasets demonstrate that our framework achieves state-of-the-art performance across clinical and linguistic metrics, with strong zero-shot generalization on IU-Xray. The proposed method significantly enhances interpretability and clinical accuracy, effectively addressing key limitations in automated radiology report generation.

Existing Vision-Language Pretraining (VLP) methods have achieved remarkable improvements across a variety of vision-language tasks, confirming their effectiveness in capturing coarse-grained semantic correlations. However, their capability for fine-grained understanding, which is critical for many nuanced vision-language applications, remains limited. Prevailing VLP models often overlook the intricate distinctions in expressing different modal features and typically depend on the similarity of holistic features for cross-modal interactions. Moreover, these models directly align and integrate features from different modalities, focusing more on coarse-grained general representations, thus failing to capture the nuanced differences necessary for tasks demanding a more detailed perception. In response to these limitations, we introduce Negative Augmented Samples(NAS), a refined vision-language pretraining model that innovatively incorporates NAS to specifically address the challenge of fine-grained understanding. NAS utilizes a Visual Dictionary(VD) as a semantic bridge between visual and linguistic domains. Additionally, it employs a Negative Visual Augmentation(NVA) method based on the VD to generate challenging negative image samples. These samples deviate from positive samples exclusively at the token level, thereby necessitating that the model discerns the subtle disparities between positive and negative samples with greater precision. Comprehensive experiments validate the efficacy of NAS components and underscore its potential to enhance fine-grained vision-language comprehension.

The impressive performance of Large Language Model (LLM) has prompted researchers to develop Multi-modal LLM (MLLM), which has shown great potential for various multi-modal tasks. However, current MLLM often struggles to effectively address fine-grained multi-modal challenges. We argue that this limitation is closely linked to the models’ visual grounding capabilities. The restricted spatial awareness and perceptual acuity of visual encoders frequently lead to interference from irrelevant background information in images, causing the models to overlook subtle but crucial details. As a result, achieving fine-grained regional visual comprehension becomes difficult. In this paper, we break down multi-modal understanding into two stages, from Coarse to Fine (CoF). In the first stage, we prompt the MLLM to locate the approximate area of the answer. In the second stage, we further enhance the model’s focus on relevant areas within the image through visual prompt engineering, adjusting attention weights of pertinent regions. This, in turn, improves both visual grounding and overall performance in downstream tasks. Our experiments show that this approach significantly boosts the performance of baseline models, demonstrating notable generalization and effectiveness. Our CoF approach is available online at https://github.com/Gavin001201/CoF.

Despite the significant success of Large Vision-Language models(LVLMs), these models still suffer hallucinations when describing images, generating answers that include non-factual objects. It is reported that these models tend to overfocus on certain irrelevant image tokens that do not contain critical information for answering the question and distort the output. To address this, we propose an Instruction-Aligned Visual Attention(IAVA) approach, which identifies irrelevant tokens by comparing changes in attention weights under two different instructions. By applying contrastive decoding, we dynamically adjust the logits generated from original image tokens and irrelevant image tokens, reducing the model’s over-attention to irrelevant information. The experimental results demonstrate that IAVA consistently outperforms existing decoding techniques on benchmarks such as MME, POPE, and TextVQA in mitigating object hallucinations. Our IAVA approach is available online at https://github.com/Lee-lab558/IAVA.

The emergence of cyber threat intelligence (CTI) is a promising approach for alleviating malicious activities. However, the effectiveness of CTIs is heavily dependent on their quality. Current literature develops the CTI quality assessment ontology mainly from the perspective of CTI source or content separately, regardless of their availability in practice. In this paper, we propose an automated CTI quality assessment method that synthesizes the trustworthiness of CTI sources and the availability of CTI contents. Specifically, we model the interactions of CTI feeds as a correlation graph and propose an iterative algorithm to well discriminate the feeds’ trustworthiness. We elaborate a CTI content assessment together with a machine learning algorithm to automatically classify CTIs’ availability from a set of content metrics. A comprehensive CTI quality assessment is proposed by jointly considering the feed trustworthiness and content availability. Extensive experimental results on real datasets demonstrate that our proposed method can quantitatively as well as effectively assess CTI quality.

Medical report generation refers to the automatic creation of accurate and coherent diagnostic reports for medical images. This task can alleviate the workload of radiologists, enhance the efficiency of disease diagnosis, and therefore holds significant value and challenges. Considering the feature differences between different modalities, existing methods primarily focus on facilitating medical report generation through cross-modal alignment of images and texts. However, since medical images are very similar to each other, it is difficult to tag obvious objects, making most methods limited to coarse-grained image-text global alignment. In this paper, we propose a medical report generation model based on adaptive topic learning and fine-grained cross-modal alignment, which aligns images and texts from medical topic perspective and token perspective. From the medical topic perspective, a global-local contrastive loss is introduced to adaptively learn efficient medical topic features, and medical topics are utilized to map images and texts to the same semantic space for fine-grained alignment. From the token perspective, a token prediction module is designed to enable the model to focus on important local information by predicting the key tokens contained in the report. Experimental results on the two public datasets (i.e. IU-Xray and MIMIC-CXR) demonstrate that our proposed model outperforms state-of-the-art baselines.

In this article, we investigate random client selection in the context of horizontal federated learning (FL), whereby only a randomly selected subset of clients transmit their model updates to the server instead of yielding all clients involved. Many researchers have demonstrated that clustering-based client selection constitutes a simple yet efficacious approach to the identification of those clients possessing representative gradient information. Despite the extensive body of research on modified selection methodologies, the majority of prior work is predicated upon the assumption of consistently effective clustering. However, raw gradient-based clustering methods are subject to several challenges: 1) poor effectiveness, the raw high-dimensional gradient of a client is too complex to serve as an appropriate feature for grouping, resulting in large intra-cluster distances and 2) fluctuating effectiveness, due to inherent limitations in clustering, the effectiveness can vary significantly, leading to clusters with diverse levels of heterogeneity. In practice, suboptimal and inconsistent clustering effects can result in clusters with low intra-cluster similarity among clients. The selection of clients from such clusters may impede the overall convergence of training. In this article, we propose FedSTS, a novel client selection scheme to accelerate the FL convergence by variance reduction. The main idea of FedSTS is to stratify a compressed model update in order to ensure an excellent grouping effect, and at the same time reduce the cross-client variance by re-allocating the sample chance among different groups based on their diverse heterogeneity. It strikes this convergence acceleration by paying more attention to those client groups with relatively low similarity and then improving the representativeness of the selected subset as much as possible. Theoretically, we demonstrate the critical improvement of the proposed scheme in variance reduction and present equivalence conditions among different client selection methods. We also present the tighter convergence guarantee of the proposed method thanks to the variance reduction. Experimental results confirm the exceeded efficiency of our approach compared to alternatives.

Radiological Report Summarization (RRS) involves automated summarization of key impressions derived from identified findings, intending to alleviate the workload and stress experienced by radiologists. Many existing RRS methods predominantly concentrate on summarizing findings, neglecting crucial clinical context, such as the patient’s previous medical examinations. This context, which is a focal point for radiologists, plays a critical role in producing comprehensive and accurate impressions. This paper endeavors to emulate the workflows of radiologists by incorporating the patient’s clinical context alongside current findings. To achieve this, we reconceptualize RRS as a conversational question-answering task, generating temporal radiological conversations. These conversations are subsequently employed to fine-tune a large chat model. The resulting radiology chatbot, RadChat, demonstrates superior performance in RRS task, showcasing the potential of integrating clinical context for more accurate impressions. Experimental results conducted on the MIMIC-CXR dataset validate the superiority of RadChat in comparison to state-of-the-art baselines.

Yufei Ma, Zihan Liang, Huangyu Dai, Ben Chen, Dehong Gao, Zhuoran Ran, Wang Zihan, Linbo Jin, Wen Jiang, Guannan Zhang, Xiaoyan Cai, Libin Yang. Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing. 2024.

The widespread adoption of Internet of Things (IoT) devices has led to increasingly complex and varied cyber-threats. Traditional defense mechanisms are often inadequate in countering these evolving threats, as attackers continuously develop new strategies. In response, this paper introduces a rapid threat detection method designed to automatically pinpoint vulnerability attacks on IoT devices amidst vast internet traffic. Our approach incorporates a multilevel clustering method, significantly accelerating the identification of malicious behaviors. Additionally, we develop a reliable assessment criterion for recognizing when a detection model becomes outdated due to the dynamic nature of network environments. This criterion is underpinned by a sophisticated combination of concept drift detection and an incremental model updating mechanism, thereby substantially enhancing the durability and effectiveness of our botnet detection models in adapting to new threats. The practicality and efficiency of our proposed solution are thoroughly validated through extensive experimental analysis, which confirms our method’s superior performance in identifying malicious behavior and ensuring the timely retraining of models to address emerging cyber-threats effectively.

Medical report generation aims at automating the synthesis of accurate and comprehensive diagnostic reports from radiological images. The task can significantly enhance clinical decision-making and alleviate the workload on radiologists. Existing works normally generate reports from single chest radiographs, although historical examination data also serve as crucial references for radiologists in real-world clinical settings. To address this constraint, we introduce a novel framework that mimics the workflow of radiologists. This framework compares past and present patient images to monitor disease progression and incorporates prior diagnostic reports as references for generating current personalized reports. We tackle the textual diversity challenge in cross-modal tasks by promoting style-agnostic discrete report representation learning and token generation. Furthermore, we propose a novel spatio-temporal fusion method with multi-granularities to fuse textual and visual features by disentangling the differences between current and historical data. We also tackle token generation biases, which arise from long-tail frequency distributions, proposing a novel feature normalization technique. This technique ensures unbiased generation for tokens, whether they are frequent or infrequent, enabling the robustness of report generation for rare diseases. Experimental results on the two public datasets demonstrate that our proposed model outperforms state-of-the-art baselines.

Click-through rate (CTR) prediction is one of the fundamental tasks in the industry, especially in e-commerce, social media, and streaming media. It directly impacts website revenues, user satisfaction, and user retention. However, real-world production platforms often encompass various domains to cater for diverse customer needs. Traditional CTR prediction models struggle in multi-domain recommendation scenarios, facing challenges of data sparsity and disparate data distributions across domains. Existing multi-domain recommendation approaches introduce specific-domain modules for each domain, which partially address these issues but often significantly increase model parameters and lead to insufficient training. In this paper, we propose a Multi-domain Low-Rank Adaptive network (MLoRA) for CTR prediction, where we introduce a specialized LoRA module for each domain. This approach enhances the model’s performance in multi-domain CTR prediction tasks and is able to be applied to various deep-learning models. We evaluate the proposed method on several multi-domain datasets. Experimental results demonstrate our MLoRA approach achieves a significant improvement compared with state-of-the-art baselines. Furthermore, we deploy it in the production environment of the Alibaba.COM 1. The online A/B testing results indicate the superiority and flexibility in real-world production environments. The code of our MLoRA is publicly available 2.

Medical report generation is a valuable and challenging task, which automatically generates accurate and fluent diagnostic reports for medical images, reducing workload of radiologists and improving efficiency of disease diagnosis. Fine-grained alignment of medical images and reports facilitates the exploration of close correlations between images and texts, which is crucial for cross-modal generation. However, visual and linguistic biases caused by radiologists' writing styles make cross-modal image-text alignment difficult. To alleviate visual-linguistic bias, this paper discretizes medical reports and introduces an intermediate modality, i.e. phrasebook, consisting of key noun phrases. As discretized representation of medical reports, phrasebook contains both disease-related medical terms, and synonymous phrases representing different writing styles which can identify synonymous sentences, thereby promoting fine-grained alignment between images and reports. In this paper, an augmented two-stage medical report generation model with phrasebook (PhraseAug) is developed, which combines medical images, clinical histories and writing styles to generate diagnostic reports. In the first stage, phrasebook is used to extract semantically relevant important features and predict key phrases contained in the report. In the second stage, medical reports are generated according to the predicted key phrases which contain synonymous phrases, promoting our model to adapt to different writing styles and generating diverse medical reports. Experimental results on two public datasets, IU-Xray and MIMIC-CXR, demonstrate that our proposed PhraseAug outperforms state-of-the-art baselines.

We present a new encoder-decoder generative network dubbed EdgeNet, which introduces a novel encoder-decoder framework for data-driven auction design in online e-commerce advertising. We break the neural auction paradigm of Generalized-Second-Price(GSP), and improve the utilization efficiency of data while ensuring the economic characteristics of the auction mechanism. Specifically, EdgeNet introduces a transformer-based encoder to better capture the mutual influence among different candidate advertisements. In contrast to GSP based neural auction model, we design an autoregressive decoder to better utilize the rich context information in online advertising auctions. EdgeNet is conceptually simple and easy to extend to the existing end-to-end neural auction framework. We validate the efficiency of EdgeNet on a wide range of e-commercial advertising auction, demonstrating its potential in improving user experience and platform revenue.

Client selection schemes are widely adopted to handle the communication-efficient problems in recent studies of Federated Learning (FL). However, the large variance of the model updates aggregated from the randomly-selected unrepresentative subsets directly slows the FL convergence. We present a novel clustering-based client selection scheme to accelerate the FL convergence by variance reduction. Simple yet effective schemes are designed to improve the clustering effect and control the effect fluctuation, therefore, generating the client subset with certain representativeness of sampling. Theoretically, we demonstrate the improvement of the proposed scheme in variance reduction. We also present the tighter convergence guarantee of the proposed method thanks to the variance reduction. Experimental results confirm the exceed efficiency of our scheme compared to alternatives.

Automatically generating the “impression” section of a radiology report given the “findings” section can summarize as much salient information of the “findings” section as possible, thus promoting more effective communication between radiologists and referring physicians. To significantly reduce the workload of radiologists, we develop and evaluate a novel framework of abstractive summarization methods to automatically generate the “impression” section of chest radiology reports. Despite recent advancements in natural language process (NLP) field such as BERT and its variants, existing abstractive summarization models and methods could not be directly applied to radiology reports, partly due to domain-specific radiology terminology. In response, we develop a pre-trained language model in the chest radiology domain, named ChestXRayBERT, to solve the problem of automatically summarizing chest radiology reports. Specifically, we first collect radiology-related scientific papers as pre-training corpus and pre-train a ChestXRayBERT on it. Then, an abstractive summarization model is proposed, which consists of the pre-trained ChestXRayBERT and a Transformer decoder. Finally, the model is fine-tuned on chest X-ray reports for the abstractive summarization task. When evaluated on the publicly available OPEN-I and MIMIC-CXR datasets, the performance of our proposed model achieves significant improvement compared with other neural networks-based abstractive summarization models. In general, the proposed ChestXRayBERT demonstrates the feasibility and promise of tailoring and extending advanced NLP techniques to the domain of medical imaging and radiology, as well as in the broader biomedicine and healthcare fields in the future.

Temporal knowledge graphs (TKGs) extrapolation reasoning predicts future events based on historical information, which has great research significance and broad application value.Existing methods can be divided into embeddingbased methods and logical rule-based methods.Embedding-based methods rely on learned entity and relation embeddings to make predictions and thus lack interpretability.Logical rule-based methods bring scalability problems due to being limited by the learned logical rules.We combine the two methods to capture deep causal logic by learning rule embeddings, and propose an interpretable model for temporal knowledge graph reasoning called adaptive logical rule embedding model for inductive reasoning (ALRE-IR).ALRE-IR can adaptively extract and assess reasons contained in historical events, and make predictions based on causal logic.Furthermore, we propose a one-class augmented matching loss for optimization.When evaluated on ICEWS14, ICEWS0515 and ICEWS18 datasets, the performance of ALRE-IR outperforms other stateof-the-art baselines.The results also demonstrate that ALRE-IR still shows outstanding performance when transferred to related dataset with common relation vocabulary, indicating our proposed model has good zero-shot reasoning ability. 1

Extractive summarization aims to produce a concise summary while retaining the key information through the way of selecting sentences from the original document. Under such background, learning inter-sentence relations has hitherto been the issue of most concern. In this study, we propose a Star architecture based model for extractive summarization (StarSum), that takes advantage of self-attention strategy based Transformer and star-shaped structure, models sentences within a document as satellite nodes and introduces a virtual star node, constructs a star model for each document to learn inter-sentence relations. Based on the constructed star-shaped model, we further develop two sentence representation learning algorithms, namely star guiding satellite (SGS) algorithm and star incorporating satellite (SIS) algorithm, in order to extract summary-worthy sentences. Experimental results on CNN/Daily Mail, New York Times (NYT) and XSum datasets prove that StarSum model achieves advanced performance for extractive summarization and has comparable performance to the state-of-the-art extractive summarization model. The results also demonstrate that the SIS algorithm is more effective than the SGS algorithm.

Data aggregation scheduling is a critical issue in WSNs. This paper studies the Delay efficient Data Aggregation scheduling problem in multi-Channel asynchronous Duty-cycled WSNs (DDACD problem), which aims to accomplish data aggregation with minimum delay. Existing studies, nevertheless, either focus on non-sleeping scenarios or assume that nodes communicate with one single channel, and thus may have poor performance if directly applied to multi-channel asynchronous duty-cycled scenarios. We first show that the DDACD problem is NP-hard. Then, we propose two new concepts of candidate active conflict graphs (CACGs) and feasible active conflict graphs (FACGs) to depict the relationship of the data aggregation links and present two coloring methods to well separate the links at different time slots or on different channels. Based on these two new concepts and two coloring methods, we propose an efficient data aggregation scheduling algorithm called EDAS, which exploits the fewest-children-first rule to choose the forwarding nodes to benefit the link scheduling. To reduce unused time slots or channels, we further propose a novel algorithm called NDAS by making full use of the characteristics of multi-channel asynchronous duty-cycled WSNs. We prove that our algorithms can achieve provable performance guarantee. The results of extensive simulations confirm the efficiency of our algorithms.

Network representation has been recently exploited for many applications, such as citation recommendation, multi-label classification and link prediction. It learns low-dimensional vector representation for each vertex in networks. Existing network representation methods only focus on incomplete aspects of vertex information (i.e., vertex content, network structure or partial integration), moreover they are commonly designed for homogeneous information networks where all the vertices of a network are of the same type. In this paper, we propose a deep network representation model that integrates network structure and the vertex content information into a unified framework by exploiting generative adversarial network, and represents different types of vertices in the heterogeneous network in a continuous and common vector space. Based on the proposed model, we can obtain heterogeneous bibliographic network representation for efficient citation recommendation. The proposed model also makes personalized citation recommendation possible, which is a new issue that a few papers addressed in the past. When evaluated on the AAN and DBLP datasets, the performance of the proposed heterogeneous bibliographic network based citation recommendation approach is comparable with that of the other network representation based citation recommendation approaches. The results also demonstrate that the personalized citation recommendation approach is more effective than the non-personalized citation recommendation approach.

Data aggregation scheduling is a critical issue in wireless sensor networks (WSNs). This paper studies the Delay efficient Data Aggregation scheduling problem in multi-Channel Duty-cycled WSNs (DDACD problem), which aims to accomplish data aggregation with minimum delay. Existing researches, nevertheless, either focus on non-sleeping scenarios, or assume that nodes communicate on one single channel, and thus have poor performance in multi-channel duty-cycled scenarios. In this paper, we first show that DDACD problem is NP-hard. We then propose two new concepts of Candidate Active Conflict Graphs (CACG) and Feasible Active Conflict Graphs (FACG) to depict the relationship of the data aggregation links, and present two coloring methods to well separate the links at different time-slots or on different channels. Based on these two new concepts and two coloring methods, we propose an Efficient Data Aggregation Scheduling algorithm called EDAS, which exploits the fewest-children-first rule to choose the forwarding nodes to benefit the link scheduling. We theoretically prove that our proposed EDAS algorithm can achieve provable performance guarantee. The results of extensive simulations confirm the efficiency of our algorithm.

Network clustering is one of the most significant tasks of network analytics. To discover network clusters, there have been many approaches proposed, utilizing network topology, or node attributes. However, there are no effective approaches that are able to discover clusters in the network with multiple modalities of attributes. In this paper, we propose a novel clustering model, called CNMMA, to discover network clusters using edge structure, and multi-modality attributes associated with vertices. Assuming edge structure, and node attributes are generated by corresponding low dimensional latent spaces (matrices), CNMMA can learn an optimal latent matrix representing the cluster membership for each vertex in the network. Besides, CNMMA makes use of an effective method to regulate the latent spaces w.r.t. edge structure and node attributes so that those vertices sharing similar edges and modality-wise attributes are more possible to be assigned with the same cluster labels. CNMMA has been tested with several real-world networks, which contain multiple modalities of node attributes, and has been compared with state-of-the-art approaches to network clustering. The experimental results show that CNMMA outperforms most approaches in most datasets. The clusters discovered by CNMMA are better matched with the ground truth.

Fast-growing scientific papers pose the problem of rapidly and accurately finding a list of reference papers for a given manuscript. Citation recommendation is an indispensable technique to overcome this obstacle. In this paper, we propose a citation recommendation approach via mutual reinforcement on a three-layered graph, in which each paper, author or venue is represented as a vertex in the paper layer, author layer, and venue layer, respectively. For personalized recommendation, we initiate the random walk separately for each query researcher. However, this has a high computational complexity due to the large graph size. To solve this problem, we apply a three-layered interactive clustering approach to cluster related vertices in the graph. Personalized citation recommendations are then made on the subgraph, generated by the clusters associated with each researcher's needs. When evaluated on the ACL anthology network, DBLP, and CiteSeer ML data sets, the performance of our proposed model-based citation recommendation approach is comparable with that of other state-of-the-art citation recommendation approaches. The results also demonstrate that the personalized recommendation approach is more effective than the nonpersonalized recommendation approach.

Current commercial mobile streaming applications call for innovative technologies for stable QoS guarantee. In this paper, we provide a comprehensive treatment of QoS guarantee through a contract-ruled approach. In particular, we envision a peer-assisted mobile peer-to-peer streaming system as a QoS trading market, where all parties involved in the system, i.e., Service Provider (SP), End User (EU), and Assisting Peers (APs), are real economic entities that are organized with contractual constraints to achieve a stable and guaranteed QoS output. The QoS trading in the market is divided into two parts. One is a basic contract that establishes the business agreement between an interested EU and a SP. We propose a QoS contingent payment to mitigate the EU's concern on the uncertainty of QoS delivery and derive an optimal contract that achieves Pareto efficiency. The other is a subcontract, in which we model transactions between the SP and contracted peers as a principal multi-agents problem, that achieves a desired joint QoS output. We further design a sharing scheme with team penalty that could overcome the free-riding problem existed in the subcontract and show that the Pareto efficiency can be achieved by setting a proper team penalty. Both numerical evaluations and prototype experiments demonstrate the effectiveness of our proposed scheme.

Peer-to-peer (P2P) streaming applications have led to the disharmony among the involved parties: Content Service Providers (CSPs), Internet Service Providers (ISPs) and P2P streaming End-Users (EUs). This disharmony is not only a technical problem at the network aspect, but also an economic problem at the business aspect. To handle this tussle, this paper proposes a profitable business model to enable all involved parties to enlarge their benefits with the help of a novel QoS-based architecture integrated with caching techniques. We model the interactions, including competition and innovation, among CSPs, ISPs and EUs as a tripartite game by introducing a pricing scheme, which captures both network and business aspects of the P2P streaming applications. We study the tripartite game in different market scenarios as more and more ISPs and CSPs involve into the market. A three-stage Stackelberg game combining with Cournot game is proposed to study the interdependent, interactive and competitive relationship among CSPs, ISPs and EUs. Moreover, we investigate how the market competition motivates ISPs to upgrade the cache service infrastructure. Our theoretical analysis and empirical study both show that the tripartite game can result in a win-win-win outcome. The market competition plays an important role in curbing the pricing power of CSPs and ISPs, and this effect is more remarkable when the amounts of CSPs and ISPs become infinite. Interestingly, we find that in the tripartite game there exists a longstop at which ISPs may have no incentive to upgrade the cache service infrastructure. However, increasing the market competition level can propel the innovation of ISPs.

In this paper, we provide a comprehensive treatment of QoS guarantee for mobile streaming applications through a contract-ruled approach. We envision a peer-to-peer streaming system as a QoS trading market, where the involved parties, Services Provider (SP), End User (EU) and assisting peers, are all real economic entities that are organized with contractual constraints for achieving a stable and guaranteed QoS output. The QoS trading in the market is classified into two parts, a basic contract that establishes the business agreement between an interested EU and a SP and a subcontract that achieves a desired joint QoS output. The proposed scheme can benefit all parties.