Papers by Cheng-Ying Chou
2019 Boston, Massachusetts July 7- July 10, 2019, 2019
IEEE Access, 2018
The dynamic thermal rating (DTR) of an extra-high voltage (EHV) power system is an important safe... more The dynamic thermal rating (DTR) of an extra-high voltage (EHV) power system is an important safety factor during dispatching power flow. The maximum line ampacity of an EHV power grid is closely related to the line temperature which can be calculated based on the real-time weather data from meteorological observation stations through the IEEE Std. 738. However, the impacts brought by varying terrains on wind speeds are not considered, which easily lead to an inaccurate estimation of line temperature and DTR. Thus, this paper used the long-term historical wind speed data to uncover which kinds of terrains might cause the risk of inaccurately estimating line temperature based on the DTR model. Then, we proposed an artificial neural network-based terrain-type wind speed correction model so that the line temperature can be estimated accurately even using weather data from climate grid. A case study illustrates that the proposed model can effectively evaluate the wind speed of a specific valley where EHV power line was deployed and further improve the accuracy of estimating its line temperature. This fact suggests that the line temperature estimated by our method can serve as a reliable reference for the power dispatching strategy. INDEX TERMS Dynamic thermal rating, line temperature, power grid, reliability, safety, terrain, wind speed.
2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC), 2018
Previously we reported the development of a PET insert for PET/MRI using strip-line signal readou... more Previously we reported the development of a PET insert for PET/MRI using strip-line signal readout and waveform sampling data acquisition for small animal imaging. Based on encouraging results obtained from the previous prototype, we have made several major upgrades for improvement. Firstly, the number of detector modules were increased from 8 to 14 to increase sensitivity and eliminate image artifacts. Each detector module consists of 8x4 LYSO arrays (3x3x10 mm3 each) and two Hamamatsu S13361-3050NE-04 MPPC arrays (4x4, 3.2 mm pitch). The detector modules are installed within a 3d-printed plastic supporting structure with 60 mm inner diameter and 115 mm outer diameter to fit inside 9.4 Tesla Bruker BioSpec 94/30 USR MR scanner. The axial field of view of the PET insert is 25.6 mm. Secondly, the SiPM signal readout multiplexing ratio is increased double in the detector module by redesigning the strip-line board;32 SiPM signals from MPPC arrays are routed to 2 strip-lines so that 16 LYSO/SiPMs send outputs to a common strip-line for readout. Experiments using the PET insert have been conducted inside and outside an MR scanner for performance evaluation. The mutual interferences of the integrated system are assessed by comparing PET and MR images of a custom-made resolution phantom. Preliminary test results are very promising and demonstrate that detector design based on strip-line signal readout is suitable for PET/MR system. We present the development of the PET insert and the preliminary experimental results.
2019 IEEE PES GTD Grand International Conference and Exposition Asia (GTD Asia), 2019
Underground power transmission cables often have to face the challenge of poor ventilation, which... more Underground power transmission cables often have to face the challenge of poor ventilation, which decreases power transmission capacity and damages the materials of the cables in a high-temperature environment. It is necessary to take a heat dissipation measure to ensure not only the safety but the efficiency of power transmission systems. Currently, for underground tunnels, two temperature reduction methods have been used. One is to exhaust heat by improving air circulation and the other is to employ chilling devices. However, even with the devices little information can be used to determine when these devices should be activated. Overusing the devices may cause high energy consumption. Additionally, underusing the devices might lead to the decrease of transmission efficiency. Therefore, this paper proposes an IoT-based underground tunnel temperature monitoring system in which the wireless transmission method used is after the experiment. Temperature sensing nodes are placed in an underground tunnel, and then a gateway collects sensed data and sends them to a database, so management personnel can monitor the temperature distribution in the tunnel in real time to determine whether ventilation devices should be activated.
Lecture Notes in Computer Science, 2022
2018 12th International Conference on Sensing Technology (ICST), 2018
Recently, particulate matter 2.5 (PM2.5) has drawn more and more attention due to the pursuit of ... more Recently, particulate matter 2.5 (PM2.5) has drawn more and more attention due to the pursuit of life quality. In Taiwan, PM2.5 concentration data mostly come from the limited static stations, and their locations are far from streets where people walk or drive by. This might cause the underestimation of PM2.5 concentration. In this paper, an on-board monitoring system is established to record the PM2.5 concentration in the surrounding areas where people live. The recorded PM2.5 concentration data are more accurate than the data from the static stations. In order to get the future PM2.5 concentration trend, the prediction model is established in this study. A long short-term memory (LSTM) and a gated recurrent unit (GRU) are used as the core of the prediction model due to their ability to analyze time series data such as the PM2.5 concentration data. And the research results show that the root mean square error (RMSE) of the prediction model using LSTM and GRU is 3.57 and 3.67 in the testing set. The prediction results can provide important air pollutant information to the public and can be used to make better air pollution control policies.
2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2017
We are developing a MR insert PET detector using SiPM for small animal imaging. Our detector desi... more We are developing a MR insert PET detector using SiPM for small animal imaging. Our detector design is based on the strip-line signal readout that we have developed to efficiently handle large amount signals for SiPM-based TOF PET. The stripline readout has an advantageous feature suitable for building PET integrated within MR. In strip-line readout, the signal digitization is accomplished remotely from the detection module, thereby the front-end electronics of the detector within MR is minimal; the interference between two systems, e.g., magnetic field distortion due to PET, can be minimized accordingly. The feasibility of the strip-line readout for PET/MR has been demonstrated in our previous study. The current prototype MR insert PET is comprised of 8 detector modules, which are installed in a plastic cylindrical supporting structure. Each detector module consists of 8x4 LYSO arrays (3x3x10 mm3each) and two Hamamatsu S13361–3050NE-04 MPPC arrays (4x4, 3.2 mm pitch); 32 SiPM signa...
2018 12th International Conference on Sensing Technology (ICST), 2018
For smart grids, suitable communication technologies and routing algorithms are very important in... more For smart grids, suitable communication technologies and routing algorithms are very important in data transmission. Among various data transmission technologies, LoRa is an Internet of Things (IoT)-based wireless communication technology, characterized by its long communication distance up to a few kilometers and low power consumption. Therefore, LoRa is an appropriate candidate for data transmission in smart grids. In this study, the performance of a LoRa device is examined. Based on the experimental results, a routing algorithm that uses the AODV is developed for the LoRa device, and the algorithm enables a long-chain topology suitable for data transmission in a smart grid. A multi-hop mechanism is simulated to ensure a high final receiving rate of packets, by finding the optimal path with the least number of hops in the transmission topology for a power transmission line. The simulation results show a great performance of the proposed algorithm in long distance transmission.
2020 8th International Electrical Engineering Congress (iEECON), 2020
In recent years, wind power generation has grown rapidly, and the accuracy prediction of wind pow... more In recent years, wind power generation has grown rapidly, and the accuracy prediction of wind power generation is very important because of the impact on the safety of power systems. However, the variations of wind speeds is extremely high, making the prediction of wind power generation quite difficult. This paper presents a 15-minute wind speed prediction model based on the recurrent neural network (RNN) with the gated recurrent unit (GRU). First, a developed anemometer is used to collect wind speed data for six months, and the data is put into a GRU model to generate the data of the next three steps and 15 minutes ahead. Finally, the accuracy of the prediction model is evaluated based on the root mean square error and the mean absolute error, and the evaluation results are compared with the results obtained by using a simple RNN model and long short-term memory model. It can be known from the evaluation indicators that the performance of the GRU model is better than the performance of the other two models.
Precision Agriculture, 2018
Currently, global warming is worsening, causing the difficulty of cultivating crops in open field... more Currently, global warming is worsening, causing the difficulty of cultivating crops in open fields, and leading to unstable quality of crops. Plant factories provide a well-controlled growth environment for precisely cultivating plants. However, uneven temperature distributions (UTDs) still occur at each cultivation shelf in plant factories, which decreases the yields (fresh weight) of plants. In this study, a wireless sensor network (WSN)-based automatic temperature monitoring and fan-circulating system for precision cultivation in plant factories is proposed, and it is built upon the technologies of WSN, ordinary kriging spatial interpolation, and automation control, to precisely find the UTD areas of cultivation shelves. Once a UTD area occurs, the fan-circulating system can be triggered immediately to automatically trace the area and circulate the air. This action can effectively improve the air flow in the cultivation zone, providing optimal growth conditions for plants. The proposed system has been deployed in two plant factories that grew Boston lettuces, and a series of performance evaluation experiments were conducted. The experimental results indicate that the fresh weight of the harvested lettuces increases by 61-109% when employing the proposed system that efficiently and significantly decreases the variation of the temperature in the cultivation zone.
Journal of Power Sources, 2018
An automatic water-cooling system is developed based on WSN technology. • An estimation method is... more An automatic water-cooling system is developed based on WSN technology. • An estimation method is developed to accurately estimate the module temperature. • The electrical properties and output power of PV module are evaluated real time. • The automatic water-cooling mechanism using WSN technology is established. • An average increase of 17.75% in energy harvested by using WSN-based cooling system.
Medical Imaging 2016: Physics of Medical Imaging, 2016
In propagation-based X-ray phase-contrast (PB XPC) imaging, the measured image contains a mixture... more In propagation-based X-ray phase-contrast (PB XPC) imaging, the measured image contains a mixture of absorption- and phase-contrast. To obtain separate images of the projected absorption and phase (i.e., refractive) properties of a sample, phase retrieval methods can be employed. It has been suggested that phase-retrieval can always improve image quality in PB XPC imaging. However, when objective (task-based) measures of image quality are employed, this is not necessarily true and phase retrieval can be detrimental. In this work, signal detection theory is utilized to quantify the performance of a Hotelling observer (HO) for detecting a known signal in a known background. Two cases are considered. In the first case, the HO acts directly on the measured intensity data. In the second case, the HO acts on either the retrieved phase or absorption image. We demonstrate that the performance of the HO is superior when acting on the measured intensity data. The loss of task-specific information induced by phase-retrieval is quantified by computing the efficiency of the HO as the ratio of the test statistic signal-to-noise ratio (SNR) for the two cases. The effect of the system geometry on this efficiency is systematically investigated. Our findings confirm that phase-retrieval can impair signal detection performance in XPC imaging.
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2015
Attenuation correction is an important step in the quantitative reconstruction of radiotracer act... more Attenuation correction is an important step in the quantitative reconstruction of radiotracer activity distribution in positron emission tomography (PET), which was typically estimated through additional transmission measurements. With the hardware advancements, time-of-flight (TOF) equipped PET systems can mitigate noise and artifacts, thereby improving the image quality. Recently, the TOF-PET has been further extended to estimate not only activity distributions, but also attenuation maps simultaneously by use of iterative algorithms. In this work, we applied the alternating-direction method of multipliers (ADMM) to simultaneously reconstruct activity and attenuation estimates in our dual-head small-animal PET system. The results were compared with those obtained by use of the maximum-likelihood algorithm activity and attenuation estimation algorithm. The computer simulation results showed that the application of the ADMM algorithm could greatly improve the image quality and reduce noisy appearance.
EJNMMI physics, 2015
Hsu and Chou: Alternating-direction method of multipliers estimation of attenuation and activity ... more Hsu and Chou: Alternating-direction method of multipliers estimation of attenuation and activity distributions in time-of-flight flat-panel positron emission tomography. EJNMMI Physics 2015 2(Suppl 1):A40.
Nuclear Science Symposium and Medical Imaging Conference, Oct 1, 2013
In the dual-head flat panel PET system (DHAPET), the unique detector arrangement leads to severe ... more In the dual-head flat panel PET system (DHAPET), the unique detector arrangement leads to severe uncertainty of depth-of-interaction (DOI) and data truncation, which in turn result in poor image quality and data loss in the reconstructed images. To improve the distortions, we proposed a reconstruction strategy under the framework of the fast iterative shrinkage-thresholding algorithm (FISTA) for minimizing total variation and de-blurring the DOI effects. Through the FISTA, the time-consuming procedure of TV-constraint can be accelerated. Additionally, we incorporated the point spread function into the reconstruction procedure of the FISTA to account for the blurring effects of DOI. Our numerical results showed that the proposed method can not only achieve a fast convergence rate to facilitate its applications, but also compensate the DOI effect and artifacts to improve image quality.
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 2012
Dual-head flat-panel positron emission tomography (PET) is the dedicated system for small-animal ... more Dual-head flat-panel positron emission tomography (PET) is the dedicated system for small-animal imaging because of its high spatial resolution and detection sensitivity. Unlike the conventional ring-based PET system, the dual-head system is versatile and can be reconfigured readily to accommodate different sample sizes and/or to achieve an optimal system performance. However, the unique imaging geometry also leads to severe depth-of-interaction (DOl) blurring. Monte Carlo simulation has been employed to account for DOl effects in the system response matrix with high accuracy, but the long simulation times make routine search for an optimal configuration impractical. To facilitate the system optimization while considering the parallax error, we employ an efficient numerical method to model the DOl effect in the system matrix for image reconstruction and accelerate the computation with the graphics processing units (GPUs). Among the system response matrices corresponding to different geometric configurations, a favorable one can be selected by exploiting the statistical detection theory. Computer simulation studies were carried out to validate and quantitatively evaluate the proposed method.
The American Journal of Surgery, 2012
BACKGROUND-Plaque vulnerability depends, in part, on composition. Imaging techniques are needed t... more BACKGROUND-Plaque vulnerability depends, in part, on composition. Imaging techniques are needed that can aid the prediction of plaque stability. High-contrast images of soft-tissue structure have been obtained with x-ray phase-contrast (PC) imaging. This research investigates multiple image radiography (MIR), an x-ray PC imaging technique, for evaluation of human carotid artery plaques. METHODS-Carotid plaques were imaged with ultrasound and subsequently excised and formalin fixed. MIR imaging was performed. By using synchrotron radiation, conventional radiographs were acquired for comparison. Image texture measures were computed for soft-tissue regions of the plaques. RESULTS-Ultrasound evaluation identified plaques as homogeneous without calcifications. MIR images revealed complex heterogeneous structure with multiple microcalcifications consistent with histology, and possessed more image texture in specific regions than conventional radiographs (P < .05). MIR refraction images allowed imaging of the geometric structure of tissue interfaces within the plaques, while scatter images contained more texture in soft-tissue regions than absorption or refraction images. CONCLUSIONS-X-ray PC imaging better depicts plaque soft-tissue heterogeneity than ultrasound or conventional radiographs. MIR imaging technique should be investigated further as a viable imaging technique to identify high-risk plaques.
International journal of nanomedicine, 2012
Ultrasound (US) sonication with microbubbles (MBs) has the potential to disrupt blood vessels and... more Ultrasound (US) sonication with microbubbles (MBs) has the potential to disrupt blood vessels and enhance the delivery of drugs into the sonicated tissues. In this study, mouse ear tumors were employed to investigate the therapeutic effects of US, MBs, and pegylated liposomal doxorubicin (PLD) on tumors. Tumors started to receive treatments when they grew up to about 15 mm(3) (early stage) with injection of PLD 10 mg/kg, or up to 50 mm(3) (medium stage) with PLD 6 (or 4) mg/kg. Experiments included the control, PLD alone, PLD + MBs + US, US alone, and MBs + US groups. The procedure for the PLD + MBs + US group was that PLD was injected first, MB (SonoVue) injection followed, and then US was immediately sonicated on the tumor. The results showed that: (1) US sonication with MBs was always able to produce a further hindrance to tumor growth for both early and medium-stage tumors; (2) for the medium-stage tumors, 6 mg/kg PLD alone was able to inhibit their growth, while it did not work...
Applied Thermal Engineering, 2012
ABSTRACT To elevate tissue temperature to therapeutic level fast with optimal power deposition du... more ABSTRACT To elevate tissue temperature to therapeutic level fast with optimal power deposition during hyperthermia treatment (HT) is a key treatment processing step. Traditionally we have treated the tumor volume, without considering possible existing thermally significant vessels, using a simple 1st-order temperature-based adaptive power scheme to determine optimal power deposition distributions. The objectives of this study were to reveal the difficulty of that approach when considering single large blood vessel, and proposed a novel fast scheme that could improve upon and substitute for the traditional temperature-based adaptive power scheme. In this study, we presented a novel three-coefficient -and-two -SCV 5th-order temperature-based adaptive power scheme to resolve the induced large blood vessel problem in 3-D temperature distribution and introduced the parameter, SCV (Sentinel Convergence Value), to handle interior scheme shift. Results of the novel adaptive power scheme has shown its robustness to fast-approach optimal temperature distribution and power density distribution with high precision in the tumor volume when considering the existence of thermally significant blood vessel. Ultimately, we may be able to effectively calculate the absorbed power density distribution of 3-D biological tissues with a complicated vasculature [1] in the volume.
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Papers by Cheng-Ying Chou