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Kwon Dohyun,Lee Chena,Chae YeonSu,Kwon Ik Jae,Kim Soung Min,Lee Jong-Ho 대한영상치의학회 2022 Imaging Science in Dentistry Vol.52 No.3
Purpose: This study aimed to evaluate the clinical usefulness of magnetic resonance (MR) neurography using the 3-dimensional double-echo steady-state with water excitation (3D-DESS-WE) sequence for the preoperative delineation of the facial and lingual nerves. Materials and Methods: Patients underwent MR neurography for a tumor in the parotid gland area or lingual neuropathy from January 2020 to December 2021 were reviewed. Preoperative MR neurography using the 3D-DESS-WE sequence was evaluated. The visibility of the facial nerve and lingual nerve was scored on a 5-point scale, with poor visibility as 1 point and excellent as 5 points. The facial nerve course relative to the tumor was identified as superficial, deep, or encased. This was compared to the actual nerve course identified during surgery. The operative findings in lingual nerve surgery were also described. Results: Ten patients with parotid tumors and 3 patients with lingual neuropathy were included. Among 10 parotid tumor patients, 8 were diagnosed with benign tumors and 2 with malignant tumors. The median facial nerve visibility score was 4.5 points. The distribution of scores was as follows: 5 points in 5 cases, 4 points in 1 case, 3 points in 2 cases, and 2 points in 2 cases. The lingual nerve continuity score in the affected area was lower than in the unaffected area in all 3 patients. The average visibility score of the lingual nerve was 2.67 on the affected side and 4 on the unaffected side. Conclusion: This study confirmed that the preoperative localization of the facial and lingual nerves using MR neurography with the 3D-DESS-WE sequence was feasible and contributed to surgical planning for the parotid area and lingual nerve.
Dohyun Kwon,Hoon Myoung 대한구강악안면병리학회 2016 대한구강악안면병리학회지 Vol.40 No.3
Extramedullary plasmacytomas (EMPs) are rare soft tissue malignant neoplasms composed of plasma cells. They are sometimes found in soft tissues. The majority of primary EMPs occur in the head and neck region, especially in the upper respiratory tract and oral cavity. We present a case of a 52-year-old female with an EMP. The patient’s initial chief complaint was swelling of the soft palate. An excisional biopsy was performed under general anesthesia. Final pathologic diagnosis was EMP of the soft palate with partial involvement of the resection margin. In order to exclude the possibility of multiple myeloma, a bone marrow exam with chromosomal study was completed. The patient was also referred to the Department of Radiation Oncology for postoperative radiation therapy (PORT); however, the patient refused to undergo PORT. The patient is currently under close observation for signs and symptoms of recurrence or metastases through regular follow-up visits and imaging studies.
Dohyun Kwon,Joongheon Kim,David A. Mohaisen,Wonjun Lee 한국통신학회 2020 Journal of communications and networks Vol.22 No.4
Video delivery and caching over the millimeter-wave(mmWave) spectrum is a promising technology for high data rateand efficient frequency utilization in many applications, includingdistributed vehicular networks. However, due to the short handoffduration, calibrating both optimal power allocation of each basestation toward its associated vehicles and cache allocation are challenging for their computational complexity. Heretofore, most videodelivery applications were based on on-line or off-line algorithms,and they were limited to compute and optimize high dimensionalobjectives within low-delay in large scale vehicular networks. Onthe other hand, deep reinforcement learning is shown for learningsuch scale of a problem with an optimized policy learning phase. In this paper, we propose deep deterministic policy gradient-basedpower control of mmWave base station (mBS) and proactive cacheallocation toward mBSs in distributed mmWave Internet-of-vehicle(IoV) networks. Simulation results validate the performance of theproposed caching scheme in terms of quality of the provisionedvideo and playback stall in various scales of IoV networks.
Kwon, Dohyun,Lee, Chena,Chae, YeonSu,Kwon, Ik Jae,Kim, Soung Min,Lee, Jong-Ho Korean Academy of Oral and Maxillofacial Radiology 2022 Imaging Science in Dentistry Vol.52 No.-
Purpose: This study aimed to evaluate the clinical usefulness of magnetic resonance (MR) neurography using the 3-dimensional double-echo steady-state with water excitation (3D-DESS-WE) sequence for the preoperative delineation of the facial and lingual nerves. Materials and Methods: Patients underwent MR neurography for a tumor in the parotid gland area or lingual neuropathy from January 2020 to December 2021 were reviewed. Preoperative MR neurography using the 3D-DESS-WE sequence was evaluated. The visibility of the facial nerve and lingual nerve was scored on a 5-point scale, with poor visibility as 1 point and excellent as 5 points. The facial nerve course relative to the tumor was identified as superficial, deep, or encased. This was compared to the actual nerve course identified during surgery. The operative findings in lingual nerve surgery were also described. Results: Ten patients with parotid tumors and 3 patients with lingual neuropathy were included. Among 10 parotid tumor patients, 8 were diagnosed with benign tumors and 2 with malignant tumors. The median facial nerve visibility score was 4.5 points. The distribution of scores was as follows: 5 points in 5 cases, 4 points in 1 case, 3 points in 2 cases, and 2 points in 2 cases. The lingual nerve continuity score in the affected area was lower than in the unaffected area in all 3 patients. The average visibility score of the lingual nerve was 2.67 on the affected side and 4 on the unaffected side. Conclusion: This study confirmed that the preoperative localization of the facial and lingual nerves using MR neurography with the 3D-DESS-WE sequence was feasible and contributed to surgical planning for the parotid area and lingual nerve.
Kwon Dohyun,Kim Dongwon,Bae Yunbi,Choi Hyoju,Kim Bongsu,최명철,An Sangmin,Lee Manhee 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.5
A quartz tuning fork is an electromechanical resonator with self-actuating and self-sensing capabilities and is widely used as a force sensor in atomic force microscopy and spectroscopy. While the electrical response of a tuning fork is affected by the two prongs’ mechanical motion and stray capacitive current, a purely mechanical motion signal of the tuning fork is required for a quantitative analysis. Here, we demonstrate the extraction of a mechanical motion signal from the electrical signal of an electrically driven quartz tuning fork in various environments, including vacuum, air, and liquid. We show that the extraction formalism is well implemented in vacuum and air, but it does not work in liquid due to the largely enhanced damping and ions present in liquids. Furthermore, using the mechanical signal extracted from the electrical signal, we determine the interaction force exerted on the tip of the tuning fork in ambient air. The present extraction method enables versatile use of electrically driven tuning forks for force, mass, and environmental sensing, in which true mechanical motion signals should be used for accurate and quantitative analysis.
Kwon, Choah,Kang, Joonhee,Kang, Woojong,Kwak, Dohyun,Han, Byungchan Elsevier 2016 ELECTROCHIMICA ACTA Vol.195 No.-
<P><B>Abstract</B></P> <P>Using first principles density functional theory (DFT) calculations we obtain thermodynamic and kinetic properties of U in an electrorefining process for spent nuclear fuels using a LiCl-KCl eutectic molten salt and Mo as a cathode. The thermodynamic stability of electrodeposited U from the molten salt onto the Mo(110) surface electrode is evaluated by activity coefficients as function of surface coverages of U and Cl. Additionally, ab-initio molecular dynamic simulations combined with the Stokes-Einstein-Sutherland relation enables us to calculate the viscosity of the LiCl-KCl eutectic molten salt. Our results well agree with previously reported experimental data endorsing the credibility. Based on our atomic-level mechanical understanding we propose that an accurate computational model system incorporating the electrochemical conditions of the electrorefining process essential for the purpose of establishing thermodynamic and kinetic database of U, otherwise critical deviations are inevitable. More interestingly, the effect of coadsorption of Cl with U on the Mo(110) surface plays a key role in stabilizing electrodeposited U on the cathode. Our approach can be useful for validating published experimental database and for identifying key factors guiding a rational design of highly efficient electrorefining system for spent nuclear fuels, and thus reducing high-level radioactive nuclear wastes.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ahn, Dohyun,Seo, Youngnam,Kim, Minkyung,Kwon, Joung Huem,Jung, Younbo,Ahn, Jungsun,Lee, Doohwang Mary Ann Liebert 2014 CYBERPSYCHOLOGY BEHAVIOR AND SOCIAL NETWORKING Vol.17 No.7
<P>This study examined the role of display size and mode in increasing users' sense of being together with and of their psychological immersion in a virtual character. Using a high-resolution three-dimensional virtual character, this study employed a 22 (stereoscopic mode vs. monoscopic modeactual human size vs. small size display) factorial design in an experiment with 144 participants randomly assigned to each condition. Findings showed that stereoscopic mode had a significant effect on both users' sense of being together and psychological immersion. However, display size affected only the sense of being together. Furthermore, display size was not found to moderate the effect of stereoscopic mode.</P>
김도현(Dohyun Kim),이병관(Byungkwan Lee),심종현(Jonghyun Shim),김청균(Chungkyun Kim),이일권(Il Kwon Lee) 한국트라이볼로지학회 2008 한국트라이볼로지학회 학술대회 Vol.2008 No.6
The connecting rod is the tribological part of automobile's engine. Since it is operated under several loads such as a compressive force, tensile force, bending force and high heat, it has proper strength and hardness. The pin-bushing bearing is a part is used at the small end of a connecting rod. It has a two part, Copper alloy and beck metal. As It contacts with a piston pin, it has good strength, lubricating ability. So in this paper, we analyze the strength safety of a pin-bushing bearing by a finite element method.