Effects of saturation temperature variation due to pressure drop of working fluid in heat exchanger on heat transfer performance

Hyoin Lee,Ji Hwan Jeong 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11

The effect of the saturation temperature drop on the heat transfer performance of a heat exchanger was analyzed under air-conditioner condensing condition, air-conditioner evaporating condition, and refrigerator evaporating condition. The thermodynamic analysis results show that the heat transfer capacity due to the pressure drop of the saturated refrigerant was at least 2.3 % and at most 91.1 % compared to the evaluated heat transfer capacity assuming no pressure loss. The rate of change of heat transfer capacity was the largest in the order of R600a, R1234yf, R134a, R410A, and R32. Heat exchanger performance simulation under practical air-conditioner operating conditions showed that the heat transfer capacity was reduced by 0.72 % due to refrigerant pressure drop under the condensing condition. On the other hand, the heat transfer capacity was increased by 26.55 % under the evaporating condition.

The Necessity for Auditory Training with Idiomatic Expressions

HyoIn Lee,Eun-Yeong Shin 한국청각언어재활학회 2023 Audiology and Speech Research Vol.19 No.4

The goal of auditory training is to improve comprehensive listening skills for the hearing impaired. Listening ability does not simply mean the level of recognizing speech sounds by distinguishing them, but also includes predicting the speaker’s intention according to the situation and context, and responding appropriately. Speakers create their utterances in a way that tries to convey their intended meaning with minimal effort under the economic principle, resulting in concise expressions that are contingent on the context and situation. Therefore, correct listening education and training should be structured to have the ability to fully understand the omitted implications and implications contained in the speaker’s speech. For auditory training for those with hearing impaired to be effective, speech perception training must extend beyond simple phonological perception by integrating one's background knowledge and communication schema within various situations and contexts. Therefore, auditory training using idiomatic expressions plays a crucial role in improving the ability to construct discourse meanings as well as comprehend the speech patterns encountered by hearing-impaired individuals in their daily communication. It is necessary to select idiomatic expressions frequently encountered in real-world communication situations and conduct auditory training by presenting transparent expressions to opaque expressions, facilitating the hearing-impaired's grasp of meaning with ease.

Change in Red / Far-red Ratio and Its Subsequent Effect on the Growth of Lettuce and Kale under Green-Converting and Far-red-Absorbing Films in Greenhouse

Hyoin Yoon,Seung Jun Lee,June Woo Lee,Jung Eek Son 한국원예학회 2017 한국원예학회 학술발표요지 Vol.2017 No.5

Blebbistatin induces chondrogenesis of single mesenchymal cells via PI3K/PDK1/mTOR/p70S6K pathway

Kim, Hyoin,Kim, Dong Hyun,Jeong, Bohyeon,Kim, Ju-Hee,Lee, Sun-Ryung,Sonn, Jong Kyung De Gruyter 2017 Biológia Vol.72 No.6

<P><B>Abstract</B></P><P>Rearrangement of the actin cytoskeleton plays an inductive role in chondrogenic differentiation. Our previous study showed that blebbistatin, an inhibitor of myosin II, removes actin stress fibres and induces chondrogenesis of mesenchymal cells in monolayer cultures. In the present study, we investigated signalling pathways implicated in the induction of chondrogenesis by dissolving actin stress fibres after blebbistatin treatment. Blebbistatin increased the activity of phosphoinositide 3-kinase (PI3K). Inhibition of PI3K with LY294002 blocked blebbistatin-induced chondrogenesis without affecting blebbistatin-induced reorganization of actin filaments. Blebbistatin also upregulated the phosphorylation of phosphoinositide-dependent protein kinase 1 (PDK1), and inhibition of PDK1 with GSK2334470 suppressed blebbistatin-induced chondrogenesis, indicating that removal of actin stress fibres by blebbistatin induced chondrogenesis by activating PI3K/PDK1. Although inhibition of Akt activity by Akt inhibitor IV blocked blebbistatin-induced chondrogenesis, phosphorylation of Akt was not affected by blebbistatin. Blebbistatin increased the phosphorylation of mammalian target of rapamycin (mTOR) at Ser2448 and p70 ribosomal protein S6 kinase (p70S6K). Inhibition of mTOR with rapamycin almost completely abolished the phosphorylation of p70S6K. Inhibition of mTOR complex 1 (mTORC1) and complex 2 (mTORC2) with pp242 diminished phosphorylation of Akt at Ser473, whereas inhibition of mTORC1 with rapamycin did not. However, blebbistatin did not affect the phosphorylation of mTOR at Ser2481. Taken together, the present results suggest that blebbistatin induces chondrogenesis by activating the PI3K/PDK1/mTOR/p70S6K pathway. Our data also indicate that Akt activity is essential for chondrogenesis but is regulated by mTORC2, which is independent of blebbistatin treatment.</P>

Novel state estimation framework for humanoid robot

Bae, Hyoin,Oh, Jun-Ho Elsevier 2017 Robotics and autonomous systems Vol.98 No.-

<P><B>Abstract</B></P> <P>This study proposes a new Kalman filter-based framework for humanoid robot state estimation. The conventional Kalman filter generates optimal estimation solutions only when the nominal equations of the model and measurement include zero-mean, uncorrelated, white Gaussian noise. Because a humanoid robot is a complex system with multiple degrees of freedom, its mathematical model is limited in terms of expressing the system accurately, resulting in the generation of non-zero-mean, non-Gaussian, correlated modeling errors. Therefore, it is difficult to obtain accurate state estimates if the conventional Kalman filter-based approaches are used with such inexact humanoid models. The proposed modified Kalman filter framework consists of two loops: a loop to estimate the state, and a loop to estimate the disturbance generated by the modeling errors (a dual-loop Kalman filter). The disturbance values estimated by the disturbance estimation loop are provided as feedback to the state estimation loop, thereby improving the accuracy of the model-based prediction process. By considering the correlation between the state and disturbance in the estimation process, the disturbance can be accurately estimated. Therefore, the proposed estimator allows the use of a simple model, even if it implies the presence of a large modeling error. In addition, it can estimate the humanoid state more accurately than the conventional Kalman filter. Furthermore, the proposed filter has a simpler structure than the existing robust Kalman filters, which require the solution of complex Riccati equations; hence, it can facilitate recursive online implementation. The performance and characteristics of the proposed filter are verified by comparison with other existing linear/nonlinear estimators using simple examples and simulations. Furthermore, the feasibility of the proposed filter is verified by implementing it on a real humanoid robot platform.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The proposed estimator framework consists of two estimator loops. </LI> <LI> One loop for the state estimation and the other loop for the disturbance estimation. </LI> <LI> The disturbance estimated in the disturbance estimation loop is provided as feedback. </LI> <LI> The correlation between state and disturbance is calculated automatically. </LI> <LI> The proposed estimator complements the fundamental limitations of the original KF. </LI> </UL> </P>

Staurosporine induces chondrogenesis of chick embryo wing bud mesenchyme in monolayer cultures through canonical and non-canonical TGF-β pathways

Kim, Hyoin,Kei, Kyungmin,Sonn, Jong Kyung Tissue Culture Association 2016 In vitro cellular & developmental biology Animal Vol.52 No.1

Biped robot state estimation using compliant inverted pendulum model

Bae, Hyoin,Oh, Jun-Ho Elsevier 2018 Robotics and autonomous systems Vol.108 No.-

<P><B>Abstract</B></P> <P>This study proposes a biped robot state estimation framework based on a compliant inverted pendulum model and a robust state estimator. A proper model that can express the key physical characteristics while considering limited computing power should be defined for the biped robot state estimation. A biped robot’s limited structural stiffness and relatively long legs compared with the cross section of the body lead to undesired flexibility. However, the models used in previous research are either not suitable for state estimation or too simple to express the essential characteristics of the biped robot. A compliant inverted pendulum model is adopted herein to enhance the estimation accuracy. This model is made by adding a virtual spring and a damper to the conventional inverted pendulum. The additional elements represent the mechanical deformation and the undesired flexible movement. Adopting this model makes it possible to reflect the important characteristics of the biped robot while taking advantage of the merits of the single-mass model. In addition, a robust state estimator that we previously proposed is adopted to compensate for the estimation error caused by the modeling error. Using these two factors, the improved COM-kinematics estimate is obtained with respect to the existing simple-model-based biped state estimators.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Humanoid robot has the flexibility feature and this disturbs the state estimation. </LI> <LI> A compliant inverted pendulum model is adopted to reflect the robot’s key feature. </LI> <LI> The previously developed robust estimator is utilized to enhance the performance. </LI> <LI> Compliant model and robust estimator based state estimation framework is suggested. </LI> </UL> </P>

친환경 하천 생태계 보존을 위한 IoT기반 하수 모니터링 및 제어 시스템 설계 및 구현

장효인(Hyoin Jang),이임건(Imgeun Lee) 한국정보통신학회 2020 한국정보통신학회 종합학술대회 논문집 Vol.24 No.1

부모의 기술수용요인이 유아의 소셜 로봇 만족도와 수용 의도에 미치는 영향

손효인(Hyoin Son),임효정(Hyojeong Lym),김다영(Dayoung Kim),김민규(Mingyu Kim),정재희(Jaehee Chung) 한국HCI학회 2024 한국HCI학회 논문지 Vol.19 No.1

부모의 양육 태도는 자녀의 신체적, 심리적, 사회적 발달에 큰 영향을 미친다. 유아의 소셜 로봇 수용에 있어서 부모의 중재는 중요한 역할을 하며 부모의 로봇에 대한 인식과 태도는 유아의 소셜 로봇 수용과 활용에 중대한 영향을 미칠 것으로 예상된다. 본 연구는 부모의 기술수용요인이 유아의 소셜 로봇 만족도와 수용 의도에 어떠한 영향을 미치는지를 살펴보기 위해 진행되었다. 먼저 문헌 연구를 통해 유아의 발달과 유아용 소셜 로봇에 대해 살펴보고, 확장된 통합기술수용모델과 로봇 관련 선행연구를 조사하였다. 실증 연구를 위해 47가구 유아를 대상으로 4일간 소셜 로봇 사용 실험을 진행한 후, 부모의 기술수용요인이 유아와 부모의 만족도와 소셜 로봇 수용 의도에 미치는 영향을 다중회귀분석을 통해 분석하였다. 연구 결과, 부모의 기술수용요인은 유아의 소셜 로봇에 대한 만족도와 수용 의도에 유의미한 영향을 미치지 않는 것으로 나타났으며, 부모의 만족도에도 유의미한 영향을 미치지 않는 것으로 나타났다. 그러나 로봇과의 실제 경험에 기반한 유아와 부모의 만족도는 유아의 소셜 로봇 수용 의도에 긍정적 영향을 미치는 것으로 나타났다. 이는 신기술에 대한 사전 인식보다는 실제 사용 경험이 수용 의도에 중대한 영향을 미친다는 사실을 보여주는 결과이다. 본 연구는 47가구를 대상으로 일정 기간 소셜 로봇을 사용하며 소셜 로봇의 수용에 영향을 미치는 요인을 검증함으로써 유아용 소셜 로봇 개발과 관련하여 의미 있는 시사점을 제시해 준다는 점에서 그 의의가 있다. Parents’ parenting attitudes have a significant impact on their infants’ physical, psychological, and social development. Parental mediation plays an important role in infants’ acceptance of social robots, and parents’ perception and attitude toward social robots is expected to have a significant impact on infants’ acceptance and use of social robots. This study was conducted to examine how parents’ technology acceptance factors affects their infants’ satisfaction with and their intention to accept social robots. First, infant development and social robots for children were reviewed through previous literature, and Extended Unified Theory of Acceptance and Use of Technology(UTAUT2) and previous research on robots based on UTAUT2 were investigated. For the empirical study, an experiment using social robots was conducted for 4 days targeting 47 households with infants, and the impact of parents’ technology acceptance factors on infants’ and parents’ satisfaction and infants’ intention to accept social robots was analyzed. As a result, it was found that parents’ technology acceptance factors did not have a significant impact on infants’ satisfaction with and their intention to accept social robots, and it appeared to have a significant impact on parents’ satisfaction neither. However, the infants’and parents’ satisfaction based on actual experience with social robots was found to have a positive impact on infants’ intention to accept social robots. This result shows that actual experience of using a new technology, rather than prior awareness of it, has a significant impact on the intention to accept. This study is significant in that it tests social robots for a certain period of time targeting 47 households, verifies the factors that affect the acceptance of social robots, and presents meaningful implications regarding the development of social robots for infants.

<지하국 대적퇴치 설화>의 분석심리학적 해석

박효인 ( Hyoin Park ) 한국분석심리학회 2016 心性硏究 Vol.31 No.1

한국 민담 지하국 대적퇴치 설화를 분석심리학적 입장에서 고찰하고 해석하였다. 이 민담은 지상의 권력자인 왕의 세 딸이 지하국 대적 아귀귀신에게 납치되니 이를 구출하고자 하는 무사가 출현하였다. 그는 들어가기에 험하고도 깊은 지하세계에 내려가서 딸들의 도움으로 지하국 대적의 거처에 잠입하여 대적 아귀귀신을 처치하였다. 영웅은 배신한 부하들 때문에 지하에서 지상으로 귀환에 어려움을 겪었으나, 노인의 도움으로 말을 타고 지상으로 날아올라 배신한 부하들을 죽이고 그가 구한 여성과 결혼하고 금은보화를 얻었다. 그리하여 왕국은 평안하여졌다. 심리학적으로 보자면 무의식의 원형적 그림자가 갑자기 무의식과 의식의 경계를 뚫고 나와 의식의 일부를 급격하게 사로잡아 그것을 무의식에 억압하여 영혼의 상실상태에 이르렀다. 무사로 표현된 자아는 깊고 험한 무의식의 여행을 통하여 무의식의 원형적 그림자의 층으로 억압된 아니마를 구출하여 의식의 세계로 데려와 결합하였고 새로운 번영된 왕국을 이룩한다. 민담은 영웅 모티브로서, 자아의 여행은 샤먼이나 무당의 입무 과정과 같은 개성화과정을 거침으로서 오래된 집단의식의 인격체계로 대표되는 이전의 왕을 새롭게 하여, 평안한 왕국을 이루는 것을 목적으로 한다. 이 민담은 집단무의식의 원형적 그림자의 특성을 드러내었으며, 개성화 과정에서의 주의해야할 태도와 방도를 우리에게 보여주고자 한다. A Korean fairy tale “The uproot of an archenemy in the underworld” is dis-cussed and interpreted from the perspective of analytical psychology. The es-sence of the story is as follows; When the three princesses were kidnapped by an archenemy in the underworld, a warrior appeared to save the princesses. He went to the underworld and killed the archenemy with the princesses help. When they tried to come back to the castle, he had difficulties because king`s soldiers betrayed him. But a old wise man and a flying horse helped him to come back to the castle. He killed the soldiers that betrayed him and married one of the princesses and got the wealth from the underworld. The kingdom could be prosperous and peace because of the marriage. The psychological meaning of the three princesses were taken by the arch-enemy is that the archetypal shadow appeared from the unconscious and grasped a part of consciousness and repressed it in unconsciousness. This sta-tus could be called the lost of soul. So the warrior ego went through an uncon-scious trip, saving his anima from the archetypal shadow, and taking her back to consciousness and renewing the collective consciousness. The ego`s trip is the individuation process like Shaman in primitive society. This fairy tale has hero motif. It reveals the feature of archetypal shadow. It also shows us man can make conscious with cautious attitude in the individuation process.