The signaling effect of group-type profile pictures on sharing economy platform

Donggyu Min,Chulho Lee 한국경영정보학회 2021 한국경영정보학회 학술대회논문집 Vol.2021 No.6

What is the Best Explainable Artificial Intelligence for Enhancing Self-Regulation Behavior in Healthcare Management? Evidence from A Randomized Field Experiment

Donggyu Min,Sunghun Chung,Chulho Lee,Wenjing Duan 한국경영정보학회 2023 한국경영정보학회 학술대회논문집 Vol.2023 No.11

Despite the widespread use of artificial intelligence (AI) in mobile healthcare apps, the need for more transparency in AI algorithms hinders their effectiveness by preventing users from understanding the reasons behind AI-based information provision. To address this challenge, various types of explainable AI (XAI) are adopted to offer transparent explanations of AI. Despite significant debates surrounding AI intervention, limited research has been devoted to whether and how various XAI types affect user behavior differently. In this study, we conducted a randomized field experiment to investigate the effectiveness of three XAI algorithms: 1) feature importance, 2) feature attribution, and 3) counterfactual explanation in promoting users' health behavior. Drawing on the self-regulated learning theory, we expect that XAI focusing on counterfactual explanation increases strategic planning and outcome expectancy, resulting in better self-regulation behavior. Our findings indicate that counterfactual explanation significantly improves users' action planning behavior, leading to a 16.5% increase in workout duration and a 3.49% increase in health records compared to the control group. Our results are salient for users with a high level of AI susceptibility due to age, goal weight loss, and AI outcome. Our finding sheds light on the potential of algorithmic explanations to improve the effectiveness of AI interventions in the healthcare industry, with practical implications for designing more transparent and user-friendly healthcare apps.

Distributed video coding supporting hierarchical GOP structures with transmitted motion vectors

Min, Kyung-Yeon,Lim, Woong,Nam, Junghak,Sim, Donggyu,Bajić,, Ivan V Springer (Biomed Central Ltd.) 2015 EURASIP journal on image and video processing Vol.2015 No.-

Synergetic effects of ligand exchange and reduction process enhancing both electrical and optical properties of Ag nanocrystals for multifunctional transparent electrodes

Kang, Min Su,Joh, Hyungmok,Kim, Haneun,Yun, Hye-Won,Kim, Donggyu,Woo, Ho Kun,Lee, Woo Seok,Hong, Sung-Hoon,Oh, Soong Ju The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.38

<P>In this work, we introduce a low cost, room-temperature and atmospheric pressure based chemical method to produce highly transparent, conductive, and flexible nano-mesh structured electrodes using Ag nanocrystals (NCs). Sequential treatments of ligand exchange and reduction processes were developed to engineer the optoelectronic properties of Ag NC thin films. Combinatorial analysis indicates that the origin of the relatively low conductivity comes from the non-metallic compounds that are introduced during ligand exchange. The reduction process successfully removed these non-metallic compounds, yielding structurally uniform, optically more transparent, dispersive, and electrically more conductive thin films. We optimized the design of Ag NC thin film mesh structures, and achieved low sheet resistance (9.12 Ω □<SUP>−1</SUP>), high optical transmittance (94.7%), and the highest figure of merit (FOM) of 6.37 × 10<SUP>−2</SUP>. Solution processed flexible transparent heaters, touch pads, and wearable sensors are demonstrated, emphasizing the potential applications of Ag NC transparent electrodes in multifunctional sensors and devices.</P>

관점지향 기법의 상황인지를 지원하는 BPEL 워크플로우 시스템

김민석 ( Min-suk Kim ),곽동규 ( Donggyu Kuak ),최종선 ( Jong-sun Choi ),최재영 ( Jae-young Choi ) 한국정보처리학회 2011 한국정보처리학회 학술대회논문집 Vol.18 No.1

표준 워크플로우 언어로 가장 인지도가 높은 BPEL은 분기를 통한 플로우선택에 있어 상황정보를 기술하기 어려워 유비쿼터스 컴퓨팅 환경에 적용하기 어렵다. 이를 위해 본 논문에서는 모듈간 낮은 결합도를 보장하는 관점지향 프로그래밍 (AOP: Aspect-Oriented Programming) 기법을 사용하여 기존 BPEL 워크플로우 시스템에 상황인지 기능을 추가한 시스템을 제안한다. 제안하는 상황인지 워크플로우 시스템은 AOP 기법을 사용하여 BPEL 워크플로우에 상황에 따른 서비스를 제공하기 위한 Context 정보를 삽입하는 방식으로 개발함으로써, 기존 BPEL 문서를 수정할 필요 없이 상황인지 기능을 적용한 워크플로우의 생성이 가능하다. 본 논문에서는 시나리오 기반의 실험을 통하여 제안한 시스템을 입증한다.

Community as a Precommitment : Enhancing Self-Control in Online Healthcare Platform

Gayoon Kim,Donggyu Min,Chulho Lee 한국경영정보학회 2023 한국경영정보학회 학술대회논문집 Vol.2023 No.11

The advent of IT in healthcare has precipitated an unprecedented digital revolution, evidenced by the growing prevalence of telemedicine platforms, mobile health applications, and an array of other digital health interventions. The impetus for this rapid acceleration can be largely attributed to the COVID-19 pandemic, which has necessitated the adoption of remote health interactions. In 2021 alone, health and fitness applications experienced a staggering 26% increase in global downloads, reaching a zenith of 2.48 billion. Despite this surge in usage, the true impact of these applications on health outcomes remains an open question, with research yielding a spectrum of results. These digital healthcare interventions, while revolutionary, do not mandate user engagement and consequently, they face similar challenges of self-control that are well-documented in the domain of traditional healthcare. Habits such as regular exercise, smoking cessation, and maintaining a healthy diet require significant self-regulation, a trait that is not automatically instilled by the mere use of digital tools. The vast majority of self-control literature has been confined to offline environments — gym attendance, strategies for quitting smoking, and healthy shopping choices — and does not fully translate to the new digital health landscape, which is characterized by its high accessibility and the ease of sharing information. Our study moves away from the traditional efficacy assessments of mobile health applications and toward understanding how online health communities (OHCs) enhance self-control among their users, particularly through emotional precommitment. These communities act as a digital agora where individuals openly share personal health records, in the unique ecosystem of OHCs, members willingly divulge their health records, using real-time information sharing as a strategic precommitment tool to reinforce self-discipline. Contrary to prior literature that often correlates self-control with offline precommitment mechanisms with financial disincentives, our research delves into the emotional dimension within OHCs. The intricate social dynamics within these communities elicit emotional responses crucial for reinforcing self-regulatory behaviors. An aspect of our research will also examine the potential modulation of the OHCs' impact on self-control by the strength of community member networks. We have collected extensive data from a widely-used health diary application, which features tens of thousands of users who provide a rich tapestry of behavioral patterns. This data forms the foundation for our hypothesis that engagement in OHCs correlates with more consistent and qualitative health record maintenance. Our findings indicate that individuals active in OHCs are more likely to consistently log their diet, enjoy improved nutritional intake, and engage in longer durations of physical activity when compared to their non-participating counterparts. Addressing potential endogeneity, we are incorporating propensity score matching (PSM) to robustly evaluate the self-control effects. A comprehensive difference-in-differences analysis is set to affirm that participation in an OHC is more than symbolic—it is a commitment mechanism fueled by emotional rather than financial incentives. Our study brings to light the underexplored domain of emotional precommitment within OHCs and highlights the platforms' potential in enhancing self-discipline. By weaving together the theory of self-control with the mechanics of online communities, we offer a new perspective that has profound implications for the design of mobile health interventions and for the academic dialogue on Information Systems. As we acknowledge the constraints of self-reported data and the call for longitudinal research to determine the enduring impact of OHCs on self-discipline, we recognize a fertile ground for future inquiry. To extend the frontiers of this research, further studies could investigate the differentiation in user engagement based on the typologies of communities and how engagement manifests distinct effects, even within the same community activities. A comprehensive understanding of the mechanisms that sustain user participation, stratified by user types, will offer critical insights into the design and facilitation of OHCs, fostering more targeted and effective digital health interventions.

블록 기반의 분산 비디오 코딩을 위한 채널 예측 기법

민경연(Kyungyeon Min),박시내(Seanae Park),유성은(Sungeun Yoo),심동규(Donggyu Sim),전병우(Byeungwoo Jeon) 大韓電子工學會 2011 電子工學會論文誌-SP (Signal processing) Vol.48 No.2

본 논문은 분산 비디오 코딩을 위하여, 수신된 움직임 벡터 기반으로 보조정보의 채널의 상태를 예측하는 기법을 제안한다. 제안한 복호기는 보조정보의 움직임 벡터를 측정하여 부호기로 전송한다. 부호기는 수신된 움직임 벡터를 기반으로 복호기의 보조정보와 동일한 예측 보조정보를 생성함으로써, 복호기의 보조정보의 성능을 측정하고, 이를 복호기로 전송한다. 또한 복호기는 수신된 오류 정보를 통하여 정확한 교차확률을 적응적으로 적용한다. 제안하는 방법은 정확한 신뢰도를 전파함으로써, 채널 복호기의 복잡도를 감소시킬 수 있으며, 적은 패리티 비트로 높은 오류정정 성능을 나타낼 수 있다. 실험 결과, 제안한 방법이 기존의 방법들과 대비하여, 비트-왜곡 성능이 증가하고 복잡도가 감소한 것을 확인 할 수 있다. In this paper, we propose a channel estimation of side information method based received motion vectors for distributed video coding. The proposed decoder estimates motion vectors of side information and transmits it to the encoder. As the proposed encoder generates side information which is the same to one in the decoder with received motion vectors, accuracy of side information of the decoder is assessed and it is transmitted to decoder. The proposed decoder can also estimate accurate crossover probability with received error information. As the proposed method conducts correct belief propagation, computational complexity of the channel decoder decreases and error correction capability is significantly improved with the smaller amount of parity bits. Experimental results show that the proposed algorithm is better in rate-distortion performance and it is faster than several conventional distributed video coding methods.

계층적 적응적 탐색과 양방향 움직임 예측을 이용한 프레임율 증가 방법

민경연(Kyungyeon Min),박시내(Seanae Park),심동규(Donggyu Sim) 대한전자공학회 2009 電子工學會論文誌-SP (Signal processing) Vol.46 No.3

본 논문은 비디오의 시간적 화질 향상을 위한 새로운 프레임율 증가 방법을 제안한다. 제안하는 방법에서는 계층적 움직임 추정 시에 탐색범위를 적응적으로 변환하는 방법을 이용하며, 움직임 보상 시 보간되지 않은 부분에 한하여 양방향 움직임 추정 및 보상과 선형 보간법을 수행한다. 부정확한 움직임 벡터 추정으로 인한 오류를 방지하기 위하여 신뢰도를 기반으로 탐색범위를 적응적으로 조절하며, 움직임 추정에 대한 신뢰도를 높이기 위하여 분산이 높은 블록 순으로 움직임 추정을 수행한다. 또한, 보간되지 않은 영역에서 배경과 객체를 분리한 후 배경인 영역에서는 선형보간법을 수행하고, 객체로 추정된 영역에서는 양방향 움직임 추정 방법을 이용하여 보간한다. 알고리즘의 성능을 평가하기 위하여 원본 프레임과 제안한 알고리즘을 이용하여 보간한 프레임 사이의 PSNR을 측정하였다. 그 결과, 화질이 기존 알고리즘보다 약 2dB 정도 개선되었으며, 블록화 현상과 몽롱화 현상이 감소한 것을 확인할 수 있었다. In this paper, we propose a frame-rate up-conversion method for temporal quality enhancement. The proposed method adaptively changes search range during hierarchical motion estimation and reconstructs hole regions using the proposed bi-direction prediction and linear interpolation. In order to alleviate errors due to inaccurate motion vector estimation, search range is adaptively changed based on reliability and for more accurate, motion estimation is performed in descending order of block variance. After segmentation of background and object regions, for filling hole regions, the pixel values of background regions are reconstructed using linear interpolation and those of object regions are compensated based on the proposed bi-directional prediction. The proposed algorithm is evaluated in terms of PSNR with original uncompressed sequences. Experimental results show that the proposed algorithm is better than conventional methods by around 2 ㏈, and blocky artifacts and blur artifacts are significantly diminished.

개 짖는 소리의 주파수 분석 및 인공신경회로망을 이용한 종 분류 시스템

김은선(Eunsun Kim),김동규(Donggyu Kim),어경재(Kyungjae Eo),민주호(Juho Min),최준혁(Junhyuk Choi),이인수(Insoo Lee) 한국정보기술학회 2023 Proceedings of KIIT Conference Vol.2023 No.11

Electron density characterization of inductively-coupled argon plasmas by the terahertz time-domain spectroscopy

Jang, Dogeun,Uhm, Han Sup,Jang, Donggyu,Hur, Min Sup,Suk, Hyyong IOP 2016 Plasma sources science & technology Vol.25 No.6

<P>Inductively-coupled plasmas (ICP) in the high electron density regime of the order of 10<SUP>13</SUP> cm<SUP>−3</SUP> are generated and their electron density characteristics are investigated by the terahertz time-domain spectroscopy (THz-TDS) method. In this experiment, the plasma was produced by RF (13.56 MHz) with an applied RF power of 300–550 W and the argon gas pressure was in the range of 0.3–1.1 Torr. We generated the THz wave by focusing a femtosecond laser pulse in air with a DC electric field. As a plasma diagnostic tool, the THz-TDS method is found to successfully provide the plasma density information in the high-density regime, where other available plasma diagnostic tools are very limited. In addition, the analytical model based on the ambipolar diffusion equation is compared with experimental observations to explain the behavior of the electron density in the ICP source, where the plasma density is shown to be related to the applied RF power and gas pressure. The analytical result from the model is found to be in good agreement with the THz-TDS result.</P>