| 1. |
- Ahmadi, Seyed Alireza, et al.
(författare)
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Towards more efficient building energy management systems
- 2012
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Ingår i: Proceedings - 2012 7th International Conference on Knowledge, Information and Creativity Support Systems, KICSS 2012. - : IEEE. - 9780769548616 ; , s. 118-125
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Konferensbidrag (refereegranskat)abstract
- As a first step towards developing efficient building energy management techniques, in this paper, we first study the energy consumption patterns of heating, ventilation and cooling (HVAC) systems across the KTH Royal Institute of Technology campus and we identify some possible areas where energy consumption can be made less wasteful. Later, we describe a test-bed where wireless sensor networks are used to collect data and eventually control the HVAC system in a distributed way. We present some of the data, temperature, humidity, and CO2 measurements, that are collected by the aforementioned network and compare them with the measurements collected by the legacy sensors already in place. In the end we present a preliminary result on modelling the dynamics of the temperature, humidity, and CO2 using the data gather by the sensor network. We check the validity of the model via comparing the out put of the system with measured data. As a future work we identify the possibility of using the models obtained here for model based control, and fault detection and isolation techniques.
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| 2. |
- Cheng, W., et al.
(författare)
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Medial reward and lateral non-reward orbitofrontal cortex circuits change in opposite directions in depression
- 2016
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Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 139:12, s. 3296-3309
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Tidskriftsartikel (refereegranskat)abstract
- The first brain-wide voxel-level resting state functional connectivity neuroimaging analysis of depression is reported, with 421 patients with major depressive disorder and 488 control subjects. Resting state functional connectivity between different voxels reflects correlations of activity between those voxels and is a fundamental tool in helping to understand the brain regions with altered connectivity and function in depression. One major circuit with altered functional connectivity involved the medial orbitofrontal cortex Brodmann area 13, which is implicated in reward, and which had reduced functional connectivity in depression with memory systems in the parahippocampal gyrus and medial temporal lobe, especially involving the perirhinal cortex Brodmann area 36 and entorhinal cortex Brodmann area 28. The Hamilton Depression Rating Scale scores were correlated with weakened functional connectivity of the medial orbitofrontal cortex Brodmann area 13. Thus in depression there is decreased reward-related and memory system functional connectivity, and this is related to the depressed symptoms. The lateral orbitofrontal cortex Brodmann area 47/12, involved in non-reward and punishing events, did not have this reduced functional connectivity with memory systems. Second, the lateral orbitofrontal cortex Brodmann area 47/12 had increased functional connectivity with the precuneus, the angular gyrus, and the temporal visual cortex Brodmann area 21. This enhanced functional connectivity of the non-reward/punishment system (Brodmann area 47/12) with the precuneus (involved in the sense of self and agency), and the angular gyrus (involved in language) is thus related to the explicit affectively negative sense of the self, and of self-esteem, in depression. A comparison of the functional connectivity in 185 depressed patients not receiving medication and 182 patients receiving medication showed that the functional connectivity of the lateral orbitofrontal cortex Brodmann area 47/12 with these three brain areas was lower in the medicated than the unmedicated patients. This is consistent with the hypothesis that the increased functional connectivity of the lateral orbitofrontal cortex Brodmann area 47/12 is related to depression. Relating the changes in cortical connectivity to our understanding of the functions of different parts of the orbitofrontal cortex in emotion helps to provide new insight into the brain changes related to depression.
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| 3. |
- Gerencser, L., et al.
(författare)
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Adaptive Input Design for LTI Systems
- 2017
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Ingår i: IEEE Transactions on Automatic Control. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9286 .- 1558-2523. ; 62:5, s. 2390-2405
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Tidskriftsartikel (refereegranskat)abstract
- Optimal input design for parameter estimation has obtained extensive coverage in the past. A key problem here is that the optimal input depends on some unknown system parameters that are to be identified. Adaptive design is one of the fundamental routes to handle this problem. Although there exist a rich collection of results on this problem, there are few results that address dynamical systems. This paper presents sufficient conditions for convergence/consistency and asymptotic optimality for a class of adaptive systems consisting of a recursive prediction error estimator and an input generator depending on the time-varying parameter estimates. The results apply to a general family of single input single output linear time-invariant systems. An important application is adaptive input design for which the results imply that, asymptotically in the sample size, the adaptive scheme recovers the same accuracy as the off-line prediction error method that uses data from an experiment where perfect knowledge of the system has been used to design an optimal input spectrum.
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| 4. |
- Huang, Boming, et al.
(författare)
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Automated trading systems statistical and machine learning methods and hardware implementation : a survey
- 2019
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Ingår i: Enterprise Information Systems. - : Taylor & Francis. - 1751-7575 .- 1751-7583. ; 13:1, s. 132-144
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Tidskriftsartikel (refereegranskat)abstract
- Automated trading, which is also known as algorithmic trading, is a method of using a predesigned computer program to submit a large number of trading orders to an exchange. It is substantially a real-time decision-making system which is under the scope of Enterprise Information System (EIS). With the rapid development of telecommunication and computer technology, the mechanisms underlying automated trading systems have become increasingly diversified. Considerable effort has been exerted by both academia and trading firms towards mining potential factors that may generate significantly higher profits. In this paper, we review studies on trading systems built using various methods and empirically evaluate the methods by grouping them into three types: technical analyses, textual analyses and high-frequency trading. Then, we evaluate the advantages and disadvantages of each method and assess their future prospects.
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| 5. |
- Huang, Boming, et al.
(författare)
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IECA : An In-Execution Configuration CNN Accelerator With 30.55 GOPS/mm(2) Area Efficiency
- 2021
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Ingår i: IEEE Transactions on Circuits and Systems Part 1. - : Institute of Electrical and Electronics Engineers (IEEE). - 1549-8328 .- 1558-0806. ; 68:11, s. 4672-4685
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Tidskriftsartikel (refereegranskat)abstract
- It remains challenging for a Convolutional Neural Network (CNN) accelerator to maintain high hardware utilization and low processing latency with restricted on-chip memory. This paper presents an In-Execution Configuration Accelerator (IECA) that realizes an efficient control scheme, exploring architectural data reuse, unified in-execution controlling, and pipelined latency hiding to minimize configuration overhead out of the computation scope. The proposed IECA achieves row-wise convolution with tiny distributed buffers and reduces the size of total on-chip memory by removing 40% of redundant memory storage with shared delay chains. By exploiting a reconfigurable Sequence Mapping Table (SMT) and Finite State Machine (FSM) control, the chip realizes cycle-accurate Processing Element (PE) control, automatic loop tiling and latency hiding without extra time slots for pre-configuration. Evaluated on AlexNet and VGG-16, the IECA retains over 97.3% PE utilization and over 95.6% memory access time hiding on average. The chip is designed and fabricated in a UMC 55-nm process running at a frequency of 250 MHz and achieves an area efficiency of 30.55 GOPS/mm(2) and 0.244 GOPS/KGE (kilo-gate-equivalent), which makes an over 2.0x and 2.1x improvement, respectively, compared with that of previous related works. Implementation of the IEC control scheme uses only a 0.55% area of the 2.75 mm(2) core.
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| 6. |
- Huang, Lirong, et al.
(författare)
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A Multi-Time-Scale Generalization of Recursive Identification Algorithm for ARMAX Systems
- 2015
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Ingår i: IEEE Transactions on Automatic Control. - 0018-9286 .- 1558-2523. ; 60:8, s. 2242-2247
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Tidskriftsartikel (refereegranskat)abstract
- Recently, Chen (2010) presented a new approach to recursive identification for ARMAX systems, which is a three-stage recursive scheme and assumes independent and identically distributed input signals. Here, we observe that, unless the time scale of the algorithm at one stage is reasonably faster than those at the previous stages, convergence to the true value may not take place. To remedy this issue, this note proposes a multi-time-scale modification of the algorithm in [ 5] such that convergence is achieved. In addition, the new scheme handles a wider class of input signals so that the input can be designed for some purpose. The advantage of the multi-time scale algorithm is verified with numerical examples.
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| 7. |
- Huang, Lirong, et al.
(författare)
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Adaptive experiment design for ARMAX systems?
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 907-912
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Konferensbidrag (refereegranskat)abstract
- A key problem in optimal input design is that the optimal input depends on some unknown system parameters that are to be identified. Adaptive design is one of the fundamental routes to handle this problem. This paper proposes an adaptive input design method for ARMAX systems based on the general stochastic framework outlined in the reference [10].
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| 8. |
- Huang, Lirong, et al.
(författare)
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Almost sure stability and stabilization of discrete-time stochastic systems
- 2015
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Ingår i: Systems & control letters (Print). - : Elsevier BV. - 0167-6911 .- 1872-7956. ; 82, s. 26-32
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Tidskriftsartikel (refereegranskat)abstract
- As is well known, noise may play a stabilizing or destabilizing role in continuous-time systems. But, for analysis and design of discrete-time systems, noise is treated as disturbance in the literature. This paper studies almost sure stability of general n-dimensional nonlinear time-varying discrete-time stochastic systems and presents a criterion based on a numerical result derived from Higham (2001), which exploits the stabilizing role of noise in discrete-time systems. As an application of the established results, this paper proposes a novel controller design method for almost sure-stabilization of linear discrete-time stochastic systems. The effectiveness of the proposed design method is verified with an example (an aircraft model subject to state-dependent noise), to which the existing results do not apply.
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| 9. |
- Huang, Lirong
(författare)
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Memoryless SMC design methods for stochastic delay systems
- 2012
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Ingår i: Asian Journal of Control. - : Wiley. - 1561-8625 .- 1934-6093. ; 14:6, s. 1496-1504
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Tidskriftsartikel (refereegranskat)abstract
- Recently, the sliding mode control (SMC) method has been extended to accommodate stochastic systems. Particularly, restrictive assumption on the structure of the control systems have been removed and a practical SMC design method for stochastic systems has been presented. This paper continues this line of research and studies the SMC methods for stochastic systems with state delay in diffusion. Both delay-independent and delay-dependent approaches are investigated. Essentially, this paper studies SMC design methods with memoryless controllers for time delay systems, which has been a problem in the past decades.
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| 10. |
- Huang, Lirong, et al.
(författare)
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On consistent estimation of farthest NMP zeros of stable LTI systems
- 2011
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Ingår i: Proceedings of the 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC11). - 9781612848006 ; , s. 5094-5099
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Konferensbidrag (refereegranskat)abstract
- Recently, identification of real-valued NMP zerosof discrete-time LTI systems has been studied in a few works. Among the key results, an adaptive input design approach is presented for consistent estimation of NMP zeros of stable LTI systems. However, this result is not applicable if the sign of the first impulse response coefficient is unknown. This paper studies the problem of estimation of the farthest NMP zeros without such prior knowledge.
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