The majority of data in businesses and industries is stored in tables, databases, and data warehouses. Reasoning with table-structured data poses significant challenges for large language models (LLMs) due to its hidden semantics, inherent complexity, and structured nature. One of these challenges is lacking an effective evaluation benchmark fairly reflecting the performances of LLMs on broad table reasoning abilities. In this paper, we fill in this gap by presenting a comprehensive table reasoning benchmark, TReB. Firstly, we propose a taxonomy to systematically measure both shallow table understanding abilities and deep table reasoning abilities, covering a total of 26 sub-tasks. We then construct a high quality dataset through a dedicated data processing and synthesis procedure. Based on these well-constructed samples, we design an evaluation framework to robustly measure table reasoning capabilities with three distinct inference modes. Experimental results with our data and framework reveal that existing LLMs still have significant room for improvement in addressing the complex and real world table related tasks. Both the dataset and evaluation framework are publicly available, with the dataset hosted on huggingface.co/datasets/JT-LM/JIUTIAN-TReB, and the framework on github.com/JT-LM/jiutian-treb.

Transformer has become one of the most popular architectures for multivariate time series (MTS) forecasting. However, existing Transformer-based methods still lack consideration of cross-time-and-channel dependency modeling, which is important to MTS forecasting. In addition, existing methods either completely ignore the channel dependency for robustness or model channel dependency at the sacrifice of robustness. How to achieve a balance between robustness and information capacity has not been investigated. To address these problems, a Transformer-based method, InjectTST, is proposed in this paper. Instead of designing a channel-dependent model directly, we retain the channel-independent backbone and restrainedly inject global information into individual channels. A joint temporal-channel attention scheme is proposed to better model the global information and a token dropout mechanism is designed to improve the model robustness and calculation efficiency. Through a Transformer-based injection module, the independent channels get improved by concentrating on useful global information. Experiments indicate that InjectTST can achieve stable improvement compared with state-of-the-art methods.

The recent boom of Transformer-based models have enhanced state-of-the-art results of multivariate time series (MTS) forecasting. However, MTS forecasting remains a challenging problem, primarily because of the intricate temporal patterns and obscured spatial correlations. Existing models are not only computationally expensive in modeling long-term temporal dependencies, but more importantly, fail to adequately capture the interrelations among variables. To address these problems, we propose STNet, a Spatial-Temporal Transformer Network with self-supervised pre-training scheme for MTS forecasting. In STNet, the MTS are formalized as a data-driven graph structure, which is learned through the training process to extract the latent patterns within the spatial dependencies of the data. Then we encode the structural information of the graph into the spatial Transformer encoder to help STNet better model refined spatial dependencies. A patch-level Transformer encoder is implemented to efficiently enhance locality and comprehensively capture semantic information pertaining to temporal dependencies. Moreover, the pre-training model generates rich contextual information, which consistently leads to reliable outcomes in transfer performance for downstream tasks. Extensive experiments conducted on five real-world benchmark datasets show the proposed STNet improves the prediction accuracy by 5.0%-25.2% compared to previous state-of-the-arts.

Cloud data centers provide end-users with a wide range of application scenarios, including scientific computing, smart grids, etc. The number and size of data centers have rapidly increased in recent years, which causes severe environmental problems and colossal power demand. Therefore, it is desirable to use a proper scheduling method to optimize resource usage and reduce energy consumption in a data center. However, it is rather difficult to design an effective and efficient task scheduling algorithm because of the dynamic and complex environment of data centers. This paper proposes a task scheduling algorithm, WSS, to optimize resource usage and reduce energy consumption based on a model-free deep reinforcement learning framework inspired by the Wolpertinger architecture. The proposed algorithm can handle the scheduling problem on a sizeable discrete action space, improve decision efficiency, and save the training convergence time. Meanwhile, the proposed algorithm based on Soft Actor-Critic is designed to improve the stability and exploration capability of WSS. Experiments based on real-world traces prove that WSS can reduce energy consumption by nearly 25% compared with the Deep Q-network task scheduling algorithm. Moreover, WSS can provide a short time of training convergence without increasing the average waiting time of tasks and achieve stable performance.

Cloud data centers (CDCs) have become increasingly popular and widespread in recent years with the growing popularity of cloud computing and high-performance computing. Due to the multi-step computation of data streams and heterogeneous task dependencies, task failure frequently occurs, resulting in poor user experience and additional energy consumption. To reduce task execution failure as well as energy consumption, we propose a novel AI-driven energy-aware proactive fault-tolerant scheduling scheme for CDCs in this paper. First, a prediction model based on the machine learning approach is trained to classify the arriving tasks into “failure-prone tasks” and “non-failure-prone tasks” according to the predicted failure rate. Then, two efficient scheduling mechanisms are proposed to allocate two types of tasks to the most appropriate hosts in a CDC. The vector reconstruction method is developed to construct super tasks from failure-prone tasks and separately schedule these super tasks and non-failure-prone tasks to the most suitable physical host. All the tasks are scheduled in an earliest-deadline-first manner. Our evaluation results show that the proposed scheme can intelligently predict task failure and achieves better fault tolerance and reduces total energy consumption better than the existing schemes.

The size and amount of colocation data centers (colocations, for short) have been growing rapidly with the increasing popularity of cloud services, which ultimately causes a heavy burden on the power grid and the environment. However, even a colocation owner wishes to reduce its energy consumption, it may not be able to apply some effective energy saving techniques directly to the servers, since the servers belong to and are operated by its tenants. To solve the "uncoordinated relationship" issue between owners and tenants and achieve the energy reduction with a limited cost budget, an energy saving-oriented incentive mechanism, ESCo is proposed in this paper. Different from existing mechanisms that emphasize on minimizing the cost for the owners, our mechanism emphasizes on the maximization of the amount of energy saved by the tenants given a limited budget that the owner wants to pay for the energy saving. An algorithm is developed to realize a stable assignment in the mechanism. Trace-driven simulations based on real-world data are performed to verify the effectiveness of ESCo. The results show that ESCo can achieve 14.47% more energy saving than existing colocation incentive mechanisms.

Colocation data centers (colocations, for short) are developing rapidly in recent years, resulting in a heavy burden on the power grid and the environment. Due to the special management mode of colocations, even the colocation operators wish to reduce their power demand, they have no authority to control the servers because the servers belong to and are operated by the tenants themselves. To solve the "uncoordinated relationship" issue between operators and tenants, a truthful and feasible incentive mechanism MesPP is proposed in this paper. Different from existing works, MesPP aims at maximizing the energy reduction of colocations with a limited cost budget and can be applied even there is no demand response (DR) program. Meanwhile, power prediction is integrated into MesPP to further improve the energy efficiency of colocations and fairness of the mechanism. To solve the optimization problem, we develop a (1−ε)-approximation algorithm. Simulations are performed and show that MesPP can achieve 12.23% more energy saving compared with existing incentive mechanisms.