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113 results on '"Cho, Jihyun"'

1. A Numerical Study of the Vibration Characteristics of a Haptic Actuator for a Dial Gear Shifter.

Author

Won, Joonsik, Ko, Kinyeong, Eom, Heesoo, Kim, Chulsook, Cho, Jihyun, and Kim, Howuk

Subjects
DRIVER assistance systems, FREQUENCIES of oscillating systems, FINITE element method, GEARING machinery vibration, TRAFFIC safety
Abstract

Featured Application: Haptic actuator, human–machine interaction. Human–machine interaction (HMI) is becoming increasingly important, especially in the automotive industry, where advancements in automated driving and driver assistance systems are key to enhancing driver safety and convenience. Among the many HMI interfaces, tactile sensing has been widely used in automotive applications as it enables instant and direct interactions with drivers. An area that remains underexplored among the tactile HMI interfaces is the application of haptic feedback to gear shifter modules. Therefore, this study investigates the design optimization of a dial gear shifter by analyzing the vibrations transmitted to the knob surface from an integrated haptic actuator. Specifically, we first tuned the mechanical properties of the haptic actuator (in terms of the resonance frequency and vibration level) in a simulation model by referring to experimental results. Next, a numerical model of a dial gear shifter was constructed, integrated with a haptic actuator, and tuned with the experimental results. The model was further optimized based on the design of the experiment and sensitivity analyses. The optimized design yielded a 24.5% improvement in the vibration level compared with the reference design, exceeding the minimum threshold (>~2.5 m/s2 at 200 Hz) required for tactile sensing. The vibration enhancement (>22.x%) was also confirmed under the simulated hand-grabbing condition. This study is technically significant as it demonstrates that the haptic vibration in a dial gear shifter can be efficiently optimized through numerical analyses. This research will be used for the actual prototyping of a dial gear shifter to provide a safe driving experience for drivers. [ABSTRACT FROM AUTHOR]

Published
2024
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7. A COP Prediction Model of Hybrid Geothermal Heat Pump Systems based on ANN and SVM with Hyper-Parameters Optimization

Author

Cho, Jihyun Shin, Jinhyun Lee, and Younghum

Subjects
hybrid geothermal heat pump system, artificial neural network, support vector machine, hyper-parameter, coefficient of performance
Abstract

When the geothermal heat pump system is operated due to an imbalance in the heating and cooling load, the system performance is lowered due to the occurrence of a thermal environment problem in the ground. To solve the performance degradation, a hybrid geothermal heat pump system with an added auxiliary heat source is used. For the efficient operation of the system, it is necessary to check the performance coefficient of the hybrid geothermal system. The coefficient of performance can be monitored based on a mathematical model using a measuring instrument. However, in the case of mathematical models, there are a lot of input data required, and many measurement sensors are required for this. If there is an input factor that is omitted among the necessary input factors, the accuracy of the predicted performance coefficient is lowered or a problem occurs that it is impossible to predict. In this study, we intend to create a model that predicts the coefficient of performance (COP) by using ANNs and SVMs that can accurately predict at low cost using small input factors. Hyper-parameter optimization is performed to increase prediction accuracy in machine learning models. We compared the accuracy of ANN and SVM-based prediction models. In this study, the ANN model showed higher CvRMSE by 5.4% and SVM by 8%. It is expected that the predictive model will be able to be used in the operation of the hybrid geothermal system in the future.

Published
2023
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10. Nationwide Survey for Current Status of Laboratory Diagnosis of Clostridioides difficile Infection in Korea

Author

Chung, Hae-Sun, primary, Park, Jeong Su, additional, Shin, Bo-Moon, additional, Yoo, Hyeon Mi, additional, Kim, Heejung, additional, Cho, Jihyun, additional, Lee, Chae Hoon, additional, Ryoo, Nam Hee, additional, Kim, Jae-Seok, additional, Chung, Jae-Woo, additional, Hong, Ki Ho, additional, Kim, You Sun, additional, and Cho, Young-Seok, additional

Published
2022
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17. VIM- and IMP-Type Metallo-[beta]-lactamase--producing Pseudomonas spp. and Acinetobacter spp. in Korean hospitals. (Dispatches)

Author

Lee, Kyungwon, Lee, Wee Gyo, Uh, Young, Ha, Gyoung Yim, Cho, Jihyun, and Chong, Yunsop

Subjects
Drug resistance in microorganisms -- Statistics
Abstract

We determined the occurrence of acquired metallo-[beta]-lactamase (MBL)--producing bacteria in Korean hospitals. Among the isolates nonsusceptible to imipenem that were collected from 28 hospitals from 2000 to 2001, 44 (11.4%) [...]

Published
2003

21. A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED)

Author

Parletta, Natalie, Zarnowiecki, Dorota M, Cho, Jihyun, Wilson, Amy, Bogomolova, Svetlana, Villani, Anthony, Itsiopoulos, Catherine, Niyonsenga, Theo, Blunden, Sarah, Meyer, Barbara J, Segal, Leonie, Baune, Bernhard, O'Dea, Kerin, Parletta, Natalie, Zarnowiecki, Dorota M, Cho, Jihyun, Wilson, Amy, Bogomolova, Svetlana, Villani, Anthony, Itsiopoulos, Catherine, Niyonsenga, Theo, Blunden, Sarah, Meyer, Barbara J, Segal, Leonie, Baune, Bernhard, and O'Dea, Kerin

Abstract

Objectives: We investigated whether a Mediterranean-style diet (MedDiet) supplemented with fish oil can improve mental health in adults suffering depression. Methods: Adults with self-reported depression were randomized to receive fortnightly food hampers and MedDiet cooking workshops for 3 months and fish oil supplements for 6 months, or attend social groups fortnightly for 3 months. Assessments at baseline, 3 and 6 months included mental health, quality of life (QoL) and dietary questionnaires, and blood samples for erythrocyte fatty acid analysis. Results: n = 152 eligible adults aged 18-65 were recruited (n = 95 completed 3-month and n = 85 completed 6-month assessments). At 3 months, the MedDiet group had a higher MedDiet score (t = 3.95, P < 0.01), consumed more vegetables (t = 3.95, P < 0.01), fruit (t = 2.10, P = 0.04), nuts (t = 2.29, P = 0.02), legumes (t = 2.41, P = 0.02) wholegrains (t = 2.63, P = 0.01), and vegetable diversity (t = 3.27, P < 0.01); less unhealthy snacks (t = −2.10, P = 0.04) and red meat/chicken (t = −2.13, P = 0.04). The MedDiet group had greater reduction in depression (t = −2.24, P = 0.03) and improved mental health QoL scores (t = 2.10, P = 0.04) at 3 months. Improved diet and mental health were sustained at 6 months. Reduced depression was correlated with an increased MedDiet score (r = −0.298, P = 0.01), nuts (r = −0.264, P = 0.01), and vegetable diversity (r = −0.303, P = 0.01). Other mental health improvements had similar correlations, most notably for increased vegetable diversity and legumes. There were some correlations between increased omega-3, decreased omega-6 and improved mental health. Discussion: This is one of the first randomized controlled trials to show that healthy dietary changes are achievable and, supplemented with fish oil, can improve mental health in people with depression.

Published
2019

24. Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

Author

Park, Dong-Chul, primary, Kim, Si Hyun, additional, Yong, Dongeun, additional, Suh, In Bum, additional, Kim, Young Ree, additional, Yi, Jongyoun, additional, Song, Wonkeun, additional, Song, Sae Am, additional, Moon, Hee-Won, additional, Lee, Hae Kyung, additional, Park, Kyoung Un, additional, Kim, Sunjoo, additional, Jeong, Seok Hoon, additional, Lee, Jaehyeon, additional, Jeong, Joseph, additional, Kim, Yu Kyung, additional, Lee, Miae, additional, Cho, Jihyun, additional, Kim, Jong-Wan, additional, Shin, Kyeong Seob, additional, Hwang, Sang-Hyun, additional, Chung, Jae-Woo, additional, Woo, Hye In, additional, Lee, Chae Hoon, additional, Ryoo, Namhee, additional, Chang, Chulhun L., additional, Kim, Hyun Soo, additional, Kim, Jayoung, additional, Shin, Jong Hee, additional, Kim, Soo Hyun, additional, Lee, Mi-Kyung, additional, Lee, Seong Gyu, additional, Jang, Sook Jin, additional, Lee, Kyutaeg, additional, Suh, HunSuk, additional, Sohn, Yong-Hak, additional, Kwon, Min-Jung, additional, Lee, Hee Joo, additional, Hong, Ki Ho, additional, Woo, Kwang-Sook, additional, Park, Chul Min, additional, and Shin, Jeong Hwan, additional

Published
2019
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30. A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED)

Author

Parletta, Natalie, primary, Zarnowiecki, Dorota, additional, Cho, Jihyun, additional, Wilson, Amy, additional, Bogomolova, Svetlana, additional, Villani, Anthony, additional, Itsiopoulos, Catherine, additional, Niyonsenga, Theo, additional, Blunden, Sarah, additional, Meyer, Barbara, additional, Segal, Leonie, additional, Baune, Bernhard T., additional, and O’Dea, Kerin, additional

Published
2017
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33. A 6-month randomised controlled trial investigating effects of Mediterranean-style diet and fish oil supplementation on dietary behaviour change, mental and cardiometabolic health and health-related quality of life in adults with depression (HELFIMED): study protocol

Author

Zarnowiecki, Dorota M, Cho, Jihyun, Wilson, Amy, Bogomolova, Svetlana, Villani, Anthony, Itsiopoulos, Catherine, Niyonsenga, Theo, O'Dea, Kerin, Blunden, Sarah, Meyer, Barbara J, Segal, Leonie, Parletta, Natalie, Zarnowiecki, Dorota M, Cho, Jihyun, Wilson, Amy, Bogomolova, Svetlana, Villani, Anthony, Itsiopoulos, Catherine, Niyonsenga, Theo, O'Dea, Kerin, Blunden, Sarah, Meyer, Barbara J, Segal, Leonie, and Parletta, Natalie

Abstract

Background: Modern diets, characterised by excess consumption of processed foods, are accompanied by an epidemic of chronic diseases. Cardiovascular disease and depression carry a large burden of disease and often occur together. Poor dietary patterns have been identified as an independent risk factor for depression while healthy diets with minimally processed food are protective. Traditional Mediterranean diets have been shown to reduce risk of cardiovascular disease; however there is a need for clinical trials in people with depression. This paper reports the study protocol of a Mediterranean-style diet intervention conducted in adults with self-reported depression. Methods/design: HELFIMED is a parallel 6-month randomised controlled trial investigating whether dietary patterns can be improved in people with depressive symptoms and whether healthier diet combined with fish oil supplementation can improve mental and cardiometabolic health and quality of life. Adults aged 18-65 years with selfreported depressive symptoms over the previous two months (N = 163) were block-randomised on age and gender between May 2014 and June 2015 to receive nutrition education, food hampers, fortnightly cooking workshops based on Mediterranean-style dietary principles for 3 months and fish oil supplementation for 6 months, or to attend fortnightly social groups (control group) for 3 months. All participants completed mental health (DASS and PANAS), quality of life, dietary and shopping and budgeting questionnaires and provided anthropometric measurements, blood and urine samples at baseline, 3 and 6 months. Additionally the treatment group attended focus groups at 3 and 6 months. Primary and secondary outcomes will be analysed using linear mixed modelling and correlations will investigate associations between improved health outcomes and subjective/objective measures of improved diet/ nutritional status.Discussion: This study will contribute causal evidence to prior observational and

Published
2016

34. A 6-month randomised controlled trial investigating effects of Mediterranean-style diet and fish oil supplementation on dietary behaviour change, mental and cardiometabolic health and health-related quality of life in adults with depression (HELFIMED): study protocol

Author

Zarnowiecki, Dorota, primary, Cho, Jihyun, additional, Wilson, Amy, additional, Bogomolova, Svetlana, additional, Villani, Anthony, additional, Itsiopoulos, Catherine, additional, Niyonsenga, Theo, additional, O’Dea, Kerin, additional, Blunden, Sarah, additional, Meyer, Barbara, additional, Segal, Leonie, additional, and Parletta, Natalie, additional

Published
2016
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36. Portable and Scalable In-vehicle Laboratory Instrumentation for the Design of i-ADAS

Author

Cho, Jihyun

Subjects
In-vehicle research plat­ form, Advanced Driving Assistance Systems, i-ADAS
Abstract

According to the WHO (World Health Organization), world-wide deaths from injuries are projected to rise from 5.1 million in 1990 to 8.4 million in 2020, with traffic-related incidents as the major cause for this increase. Intelligent, Advanced Driving Assis­ tance Systems (i-ADAS) provide a number of solutions to these safety challenges. We developed a scalable in-vehicle mobile i-ADAS research platform for the purpose of traffic context analysis and behavioral prediction designed for understanding fun­ damental issues in intelligent vehicles. We outline our approach and describe the in-vehicle instrumentation.

Published
2011

49. A Bidirectional Neural Interface Circuit With Active Stimulation Artifact Cancellation and Cross-Channel Common-Mode Noise Suppression.

Author

Mendrela, Adam E., Cho, Jihyun, Fredenburg, Jeffrey A., Nagaraj, Vivek, Netoff, Theoden I., Flynn, Michael P., and Yoon, Euisik

Subjects
ELECTRONIC circuits, COMPLEMENTARY metal oxide semiconductors, NEURAL stimulation, ELECTRIC noise, ANALOG-to-digital converters
Abstract

This work presents a bidirectional neural interface circuit that enables simultaneous recording and stimulation with a stimulation artifact cancellation circuit. The system employs a common average referencing (CAR) front-end circuit to suppress cross-channel environmental noise to further facilitate use in clinical environment. This paper also introduces a new range-adapting (RA) SAR ADC to lower the system power consumption. A prototype is fabricated in 0.18\;\mu \rmm CMOS and characterized and tested in vivo in an epileptic rat model. The prototype attenuates stimulation artifacts by up to 42 dB and suppresses cross-channel noise by up to 39.8 dB. The measured power consumption per channel is 330 nW, while the area per channel is 0.17 mm$^2$. [ABSTRACT FROM PUBLISHER]

Published
2016
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