Wan-Ki Park

Dr. Wan-Ki Park


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2007
Verified
Conference Paper
Closed access
WPWan-Ki Park
Wan-Ki Park
CCChang-Sic Choi
Chang-Sic Choi
JHJinsoo Han
Jinsoo Han
IHIntark Han
Intark Han
There are many various CE (consumer electronics) home appliances being controlled and managed with each different remote control unit based on IR(Infra-Red) signal in our home environments. A universal remote control (URC) unit is an integrated device for controlling these various devices (with a single one). To control them based on IR control signal, the URC unit has to have many pre-programmed control codes for controlling them because each home appliance is controlled with each its identical IR control profile. In case of appliances from different vendors, the IR profile for two different CE devices may be represented with different format even though the type of these appliances is same, such as television sets. In this paper, we propose a novel ZigBee based URC, called Z-URC in this paper, applicable to multiple legacy home appliances. The proposed Z-URC controls dynamically multiple legacy IR controllable digital CE appliances based on IEEE802.15.4, especially ZigBee protocol. The proposed scheme consists of two main components; Z-URC(ZigBee based Universal Remote Control) and Z2IR(ZigBee to IR) conversion module. The one is an integrated remote control unit using ZigBee based wireless network technology, WPAN(wireless personal area network) and the other is a Z2IR(ZigBee to IR) conversion module which converts a control message transferred through the ZigBee network into an IR typed control signal. In the proposed scheme, the list of CE devices to be controlled by the proposed URC is dynamically reconfigured. It is based on his location as a consumer with the proposed Z-URC goes from a room to any other place in his house. The Z-URC gets some information for its controllable devices' product identifier (ID) and vendor ID from WPAN (wireless personnel area network) based on ZigBee. A user may configure the two IDs for his CE appliances. Based on this feature, the module informs the Z-URC a target appliance's information. And, we apply a novel mechanism to our proposed scheme to minimize power consumption of the Z2IR module, which is based on ZigBee devices' ON/OFF control mechanism using multiple timers.

6 December 2023 in Energies
Verified
Journal Article
Open access
PDF file
JJJaeik Jeong
Jaeik Jeong
TKTai-Yeon Ku
Tai-Yeon Ku
WPWan-Ki Park
Wan-Ki Park
With recent advancements in data technologies, particularly machine learning, research focusing on the enhancement of energy efficiency in residential, commercial, and industrial settings through the collection of load data, such as heat, electricity, and gas, has gained significant attention. Nevertheless, issues arising from hardware- or network-related problems can result in missing data, necessitating the development of management techniques to mitigate these challenges. Traditional methods for missing imputation face difficulties when operating in constrained environments characterized by short data collection periods and frequent consecutive missing. In this paper, we introduce the denoising masked autoencoder (DMAE) model as a solution to improve the handling of missing data, even in such restrictive settings. The proposed DMAE model capitalizes on the advantages of the denoising autoencoder (DAE), enabling effective learning of the missing imputation process, even with relatively small datasets, and the masked autoencoder (MAE), allowing for learning in environments with a high missing ratio. By integrating these strengths, the DMAE model achieves an enhanced performance in terms of missing imputation. The simulation results demonstrate that the proposed DMAE model outperforms the DAE or MAE significantly in a constrained environment where the duration of the training data is short, less than a year, and missing values occur frequently with durations ranging from 3 h to 12 h.

19 May 2016 in ETRI Journal
Verified
Journal Article
Closed access
PDF file
JJJin-Doo Jeong
Jin-Doo Jeong
SLSang-Kyu Lim
Sang-Kyu Lim
JHJinsoo Han
Jinsoo Han
WPWan-Ki Park
Wan-Ki Park
ILIlwoo Lee
Ilwoo Lee
CJChong-Wha Jong
Chong-Wha Jong

28 October 2023 in Energies
Verified
Journal Article
Open access
PDF file
JLJeongin Lee
Jeongin Lee
JCJongwoo Choi
Jongwoo Choi
WPWan-Ki Park
Wan-Ki Park
ILIlwoo Lee
Ilwoo Lee
Renewable energy sources are being expanded globally in response to global warming. Solar power generation is closely related to solar radiation and typically experiences significant fluctuations in solar radiation hours during periods of high solar radiation, leading to substantial inaccuracies in power generation predictions. In this paper, we suggest a solar power generation prediction method aimed at minimizing prediction errors during solar time. The proposed method comprises two stages. The first stage is the construction of the Solar Base Model by extracting characteristics from input variables. In the second stage, the prediction error period is detected using the Solar Change Point, which measures the difference between the predicted output from the Solar Base Model and the actual power generation. Subsequently, the probability of a weather forecast state change within the error occurrence period is calculated, and this information is used to update the power generation forecast value. The performance evaluation was restricted to July and August. The average improvement rate in predicted power generation was 24.5%. Using the proposed model, updates to weather forecast status information were implemented, leading to enhanced accuracy in predicting solar power generation.

22 November 2024 in Energies
Verified
Journal Article
Open access
PDF file
JJJaeik Jeong
Jaeik Jeong
TKTai-Yeon Ku
Tai-Yeon Ku
WPWan-Ki Park
Wan-Ki Park
In recent research addressing energy arbitrage with energy storage systems (ESSs), discrete reinforcement learning (RL) has often been employed, while the underlying reasons for this preference have not been explicitly clarified. This paper aims to elucidate why discrete RL tends to be more suitable than continuous RL for energy arbitrage problems. When using continuous RL, the charging and discharging actions determined by the agent often exceed the physical limits of the ESS, necessitating clipping to the boundary values. This introduces a critical issue where the learned actions become stuck at the state of charge (SoC) boundaries, hindering effective learning. Although recent advancements in constrained RL offer potential solutions, their application often results in overly conservative policies, preventing the full utilization of ESS capabilities. In contrast, discrete RL, while lacking in granular control, successfully avoids these two key challenges, as demonstrated by simulation results showing superior performance. Additionally, it was found that, due to its characteristics, discrete RL more easily drives the ESS towards fully charged or fully discharged states, thereby increasing the utilization of the storage system. Our findings provide a solid justification for the prevalent use of discrete RL in recent studies involving energy arbitrage with ESSs, offering new insights into the strategic selection of RL methods in this domain. Looking ahead, improving performance will require further advancements in continuous RL methods. This study provides valuable direction for future research in continuous RL, highlighting the challenges and potential strategies to overcome them to fully exploit ESS capabilities.

17 May 2024 in arXiv
Verified
Preprint
Open access
PDF file
JJJaeik Jeong
Jaeik Jeong
TKTai-Yeon Ku
Tai-Yeon Ku
WPWan-Ki Park
Wan-Ki Park
Energy storage devices, such as batteries, thermal energy storages, and hydrogen systems, can help mitigate climate change by ensuring a more stable and sustainable power supply. To maximize the effectiveness of such energy storage, determining the appropriate charging and discharging amounts for each time period is crucial. Reinforcement learning is preferred over traditional optimization for the control of energy storage due to its ability to adapt to dynamic and complex environments. However, the continuous nature of charging and discharging levels in energy storage poses limitations for discrete reinforcement learning, and time-varying feasible charge-discharge range based on state of charge (SoC) variability also limits the conventional continuous reinforcement learning. In this paper, we propose a continuous reinforcement learning approach that takes into account the time-varying feasible charge-discharge range. An additional objective function was introduced for learning the feasible action range for each time period, supplementing the objectives of training the actor for policy learning and the critic for value learning. This actively promotes the utilization of energy storage by preventing them from getting stuck in suboptimal states, such as continuous full charging or discharging. This is achieved through the enforcement of the charging and discharging levels into the feasible action range. The experimental results demonstrated that the proposed method further maximized the effectiveness of energy storage by actively enhancing its utilization.