Recent studies show that diffusion models (DMs) are vulnerable to backdoor attacks. Existing backdoor attacks impose unconcealed triggers (e.g., a gray box and eyeglasses) that contain evident patterns, rendering remarkable attack effects yet easy detection upon human inspection and defensive algorithms. While it is possible to improve stealthiness by reducing the strength of the backdoor, doing so can significantly compromise its generality and effectiveness. In this paper, we propose UIBDiffusion, the universal imperceptible backdoor attack for diffusion models, which allows us to achieve superior attack and generation performance while evading state-of-the-art defenses. We propose a novel trigger generation approach based on universal adversarial perturbations (UAPs) and reveal that such perturbations, which are initially devised for fooling pre-trained discriminative models, can be adapted as potent imperceptible backdoor triggers for DMs. We evaluate UIBDiffusion on multiple types of DMs with different kinds of samplers across various datasets and targets. Experimental results demonstrate that UIBDiffusion brings three advantages: 1) Universality, the imperceptible trigger is universal (i.e., image and model agnostic) where a single trigger is effective to any images and all diffusion models with different samplers; 2) Utility, it achieves comparable generation quality (e.g., FID) and even better attack success rate (i.e., ASR) at low poison rates compared to the prior works; and 3) Undetectability, UIBDiffusion is plausible to human perception and can bypass Elijah and TERD, the SOTA defenses against backdoors for DMs. Code is available at https://github.com/TheLaoLab/UIBDiffusion.

Recent research shows that large language models (LLMs) are vulnerable to hijacking attacks under the scenario of in-context learning (ICL) where LLMs demonstrate impressive capabilities in performing tasks by conditioning on a sequence of in-context examples (ICEs) (i.e., prompts with task-specific input-output pairs). Adversaries can manipulate the provided ICEs to steer the model toward attacker-specified outputs, effectively ''hijacking'' the model's decision-making process. Unlike traditional adversarial attacks targeting single inputs, hijacking attacks in LLMs aim to subtly manipulate the initial few examples to influence the model's behavior across a range of subsequent inputs, which requires distributed and stealthy perturbations. However, existing approaches overlook how to effectively allocate the perturbation budget across ICEs. We argue that fixed budgets miss the potential of dynamic reallocation to improve attack success while maintaining high stealthiness and text quality. In this paper, we propose BAM-ICL, a novel **b**udgeted **a**dversarial **m**anipulation hijacking attack framework for in-context learning. We also consider a more practical yet stringent scenario where ICEs arrive sequentially and only the current ICE can be perturbed. BAM-ICL mainly consists of two stages: In the offline stage, where we assume the adversary has access to data drawn from the same distribution as the target task, we develop a global gradient-based attack to learn optimal budget allocations across ICEs. In the online stage, where ICEs arrive sequentially, perturbations are generated progressively according to the learned budget profile. We evaluate BAM-ICL on diverse LLMs and datasets. The experimental results demonstrate that it achieves superior attack success rates and stealthiness, and the adversarial ICEs are highly transferable to other models.

Hand Pose Estimation (HPE) is a crucial technique for human-computer interaction perception. Recent works have shown that leveraging temporal information yields significant importance in the stability of the HPE system. However, existing sequential optimization methods are mainly designed for specific frameworks, limiting their applicability and generalization potential. To solve these problems, we propose a model-agnostic Sequential hand pose Optimization Network (SO-Net), which can be applicable to various HPE methods. Specifically, SO-Net first utilizes a feature-heterogeneous pre-embedding module that unifies multiple types of features in a coherent manner and facilitates their effective interactions. Then it adopts a transformer-based spatial-temporal network to capture the long-range information across frames. Finally, to enhance the robustness of the model, a dense refinement process is employed for further optimization. Our framework outperforms state-of-the-art methods on NYU and DexYCB datasets and also provides optimization advantages across various frameworks.

Microservice architectures, characterized by their loosely coupled services and complex call patterns, have become predominant in cloud applications, benefiting from elastic scalability and development agility. However, they face challenges in anomaly propagation and root cause analysis (RCA), often depending on the operational knowledge and system familiarity. FlowRCA, a non-invasive RCA framework, addresses these challenges by leveraging common monitoring metrics like CPU load, memory usage, and container latency to facilitate RCA in microservice environments. By analyzing causal relationships between metrics, FlowRCA clarifies fault propagation complexities, enabling accurate and comprehensive failure diagnosis. Experimental evidence shows FlowRCA’s superiority over existing algorithms, effectively identifying faulty microservices and root cause metrics in simulated environments.

Accomplishing a program task usually involves performing multiple activities in a logical order. Task-solving activities may have different relationships, such as subactivityof, precede-follow, and different attributes, such as location, condition, API, code. We refer to task-solving activities and their relationships and attributes as know-how knowledge. Programming task know-how knowledge is commonly documented in semi-structured textual tutorials. A formative study of the 20 top-viewed Android-tagged how-to questions on Stack Overflow suggests that developers are faced with three information barriers (incoherent modeling of task intent, tutorial information overload and unstructured task activity description) for effectively discovering and understanding task-solving knowledge in textual tutorials. Knowledge graph has been shown to be effective in representing relational knowledge and supporting knowledge search in a structured way. Unfortunately, existing knowledge graphs extract only know-what information (e.g., APIs, API caveats and API dependencies) from software documentation. In this paper, we devise open information extraction (OpenIE) techniques to extract candidates for task activities, activity attributes and activity relationships from programming task tutorials. The resulting knowledge graph, TaskKG, includes a hierarchical taxonomy of activities, three types of activities relationships and five types of activity attributes, and enables activity-centric knowledge search. As a proof-of-concept, we apply our approach to Android Developer Guide. A comprehensive evaluation of TaskKG shows high accuracy of our OpenIE techniques. A user study shows that TaskKG is promising in helping developers finding correct answers to programming how-to questions.

In IaaS cloud environments, peak memory demand caused by hotspot applications in Virtual Machine (VM) often results in performance degradation within and outside of this VM. Some solutions such as host swapping and ballooning for memory consolidation and overcommitment have been proposed. These solutions, however, have no help for addressing guest swapping issues inside VM. Even though host holds sufficient memory pages, guest OS is unable to utilize free pages in host directly due to the semantic gap between VMM and it. Our goal is to alleviate the performance degradation by decreasing disk I/O operations generated by guest swapping. Based on the insight analysis of behavioral features of guest swapping, we design HybridSwap, a distributed scalable framework which organize surplus memory in all hosts within data center into virtual pools for swapping. This framework builds up a synthetic swapping mechanism in a peer-to-peer way, which VM can adaptively choose suitable pools for swapping. We implement the prototype of HybridSwap and evaluate it with different benchmarks. The results demonstrate that our solution has the ability to promote the guest swapping efficiency indeed. Even in some cases, it shows 2-5 times of performance promotion compared with the baseline setup.

The networked application environment has motivated the development of multitasking operating systems for sensor networks and other low-power electronic devices, but their multitasking capability is severely limited because traditional stack management techniques perform poorly on small-memory systems without virtual memory support. In this paper, we show that combining binary translation and a new kernel runtime can lead to efficient OS designs on resource constrained platforms. We introduce SenSmart, a multitasking OS for sensor networks, and present new OS design techniques for supporting preemptive multitask scheduling, memory isolation, and adaptive stack management. Our solution provides memory isolation and automatic stack relocation on usual sensornet platforms. The adaptive stack management frees programmers from the burden of estimating tasks' stack usage, yet it enables SenSmart to schedule and run more tasks than other multitasking OSes for sensor networks. We have implemented SenSmart on MICA2/MICAz motes. Evaluation shows that SenSmart has a significantly better capability in managing concurrent tasks than other sensornet operating systems.

Increasing Internet business and computing footprint motivate server consolidation in data centers. Through virtualization technology, server consolidation can reduce physical hosts and provide scalable services. However, the ineffective memory usage among multiple virtual machines (VMs) becomes the bottleneck in server consolidation environment. Because of inaccurate memory usage estimate and the lack of memory resource managements, there is much service performance degradation in data centers, even though they have occupied a large amount of memory. In order to improve this scenario, we first introduce VM's memory division view and VM's free memory division view. Based on them, we propose a hierarchal memory service mechanism. We have designed and implemented the corresponding memory scheduling algorithm to enhance memory efficiency and achieve service level agreement. The benchmark test results show that our implementation can save 30% physical memory with 1% to 5% performance degradation. Based on Xen virtualization platform and balloon driver technology, our works actually bring dramatic benefits to commercial cloud computing center which is providing more than 2,000 VMs' services to cloud computing users.

A kind of strategy decision-making risk analysis method is put forward based on uncertain event analysis, on the basis of potential uncertain events confronted in decision-makings. In this method, a model is constructed to generate the decision-making option space, with detailed generation ways based on the risks of uncertain events. By comparing the potential capacities of the enemy, self-army and the third party, the occurrence probabilities and consequent losses of uncertain events are quantified. Extreme event samples were selected by means of conditional expectation to obtain the quantified description of each risk. Three ways of analyzing the quantified results are proposed.

The networked application environment has motivated the development of multitasking operating systems for sensor networks and other low-power electronic devices, but their multitasking capability is severely limited because traditional stack management techniques perform poorly on small memory systems. In this paper, we show that combining binary translation and a new kernel runtime can lead to efficient OS designs on resource-constrained platforms. We introduce SenSmart, a multitasking OS for sensor networks, and present new OS design techniques for supporting preemptive multi-task scheduling, memory isolation, and versatile stack management. We have implemented SenSmart on MICA2/MICAz motes. Evaluation shows that SenSmart performs efficient binary translation and demonstrates a significantly better capability in managing concurrent tasks than other sensor net operating systems.

As one of the components in iVCE software platform, iVCE/M devotes to the performance improvement of the I/O-intensive and memory-intensive applications with efficient aggregation of distributed memory resources. To facilitate the deployment of iVCE/M, the data locating algorithm with balanced time and space cost, as well as the transparent interface for the legacy applications without code modification, are both significant in the implementation of iVCE/M. We propose the logarithmic search tree based client-side metadata structure to accelerate the data locating using moderate memory consumption, the implicit I/O redirection mechanism, and the implementation of iVCE/M based disk cache system. The experiments with cross domain emulation prove that the scheme is applicable to exploit the distributed memory resources for applications with small granularity I/O accesses.

We propose FIT, a flexible, lightweight, and real-time scheduling system for wireless sensor platforms. There are three salient features of FIT. First, its two-tier hierarchical framework supports customizable application-specific scheduling policies, hence, FIT is very flexible. Second, FIT is lightweight in terms of minimizing the thread number to reduce preemptions and memory consumption while at the same time ensuring system schedulability. We propose a novel Minimum Thread Scheduling Policy (MTSP) exploration algorithm within FIT to achieve this goal. Finally, FIT provides a detailed real-time schedulability analysis method to help check if application's temporal requirements can be met. We implemented FIT on MicaZ motes and carried out extensive evaluations. Results demonstrate that FIT is indeed flexible and lightweight for implementing real-time applications, at the same time, the schedulability analysis provided can predict the real-time behavior. FIT is a promising scheduling system for implementing complex real-time applications in sensor networks.

As an innovative distributed computing technique for sharing the memory resources in high-speed network, RAM Grid exploits the distributed free nodes, and provides remote memory for the nodes which are short of memory. One of the RAM Grid systems named DRACO, tries to provide cooperative caching to improve the performance of the user node which has mass disk I/O but lacks local memory. However, the performance of DRACO is constrained with the network communication cost. In order to hide the latency of remote memory access and improve the caching performance, we proposed using push- based prefetching to enable the caching providers to push the potential useful memory pages to the user nodes. Specifically, for each caching provider, it employs sequential pattern mining techniques, which adapts to the characteristics of memory page access sequences, on locating useful memory pages for prefetching. We have verified the effectiveness of the proposed method through system analysis and trace-driven simulations.

As an application of large scale distributed network computing system, RAM Grid tries to solve the problem of memory resource sharing and utilization. Due to the special properties of memory, traditional resource information management approaches cannot be adapted easily. This paper proposes a clustering based resource aggregating scheme under the background of RAM Grid, which can reduce the scale of resource information management efficiently. With analogy to the force field and potential energy theory in physics, the basic model, the force field-potential energy model, and the corresponding distributed algorithms are proposed, respectively. The model and algorithms are also evaluated by real network topologies based simulation.

Memory-intensive applications often suffer from the poor performance of disk swapping when memory is inadequate. Remote memory sharing schemes, which provide a remote memory that is faster than the local hard disk, are able to improve the performance of such applications. Due to the limitation of being applicable within single clusters only, however, most of the previous remote memory mechanisms, such as the network memory scheme, fail to be extendable into a large scale, distributed, heterogeneous, and dynamic environment. In this work, we propose a service-oriented grid memory sharing scheme, distributed paging RAM grid (DPRG). We study the properties and criteria of large scale memory sharing, and then design major operations and optimizations to fit the usage of grid systems. We collect trace from our grid environment, and evaluate DPRG through comprehensive trace-driven simulations. Results show that DPRG significantly outperforms existing remote memory sharing schemes and supports grid computing applications effectively