스마트토이를 위한 애플리케이션 사용성 평가 연구

조동환,최훈,Cho, Donghwan,Choi, Hun 한국정보통신학회 2019 한국정보통신학회논문지 Vol.23 No.11

최근 소프트웨어의 중요성이 증가함에 따라 국내에서도 초등학교에서 소프트웨어 교육이 의무화되고 있다. 이러한 시점에서 스마트토이를 이용하여 놀이와 교육을 접목한 코딩 교육이 이루어지고 있다. 다양한 스마트토이 중 가장 널리 이용되고 있는 스마트 토이 중 하나는 블록형 스마트 토이이다. 본 연구에서는 블록형 스마트토이를 조작할 수 있는 스마트폰 애플리케이션에 대한 사용자의 사용성을 향상시키기 위한 평가를 실시하였다. 이를 위해 다양한 사용성 평가 기법 중 하나인 전문가를 대상으로 한 휴리스틱 기법을 실시하였다. 분석 결과, 메뉴의 버튼과 스위치 구분이 잘 이루어지지 않았으며, 오류 발생 시 발생 원인이 사용자에게 제공되지 않는 것으로 나타났다. 본 연구 결과는 향후 스마트토이를 위한 애플리케이션의 사용성을 향상시키는데 기반이 될 수 있다. With the recent increase in the importance of software, software education is required in elementary schools in Korea. At this point, coding education combining play and education using smart toys is widely used. One of the most widely used smart toys is a block type smart toy. In this study, usability evaluation was performed to improve user's usability for block type smart toy with smartphone application. In order to achieve the purpose of this study, a heuristic technique with experts, one of various usability evaluation techniques, was performed. As a result of the analysis, it was found that the buttons and the switch of the menu were not well distinguished, and the cause of the error was not provided to the user. The results of this study can be the basis for improving the usability of applications for smart toy in the future.

유리섬유/나일론 6 복합재료의 계면특성에 미치는 Chloropropyl 말단기를 가진 실란결합체 농도의 영향

조동환,윤숙향,방대석,김준경,임순호,박민,Cho, Donghwan,Yun, Suk Hyang,Bang, Dae-Suk,Kim, Junkyung,Lim, Soonho,Park, Min 한국접착및계면학회 2004 접착 및 계면 Vol.5 No.1

본 연구에서는 사슬말단에 chloropropyl 유기관능그룹을 가지고 있는 실란결합체인 3-chloropropyltrimethoxysilane(CTMS)을 사용하여 여러 농도에서 유리섬유 표면에 사이징 처리하여 유리섬유/나일론 6 및 유리직물/나이론 6 복합재료를 제조하였다. 단섬유 microbonding 시험에 의한 유리섬유/나일론 6 복합재료의 계면전단강도와 short-beam 전단시험과 동역학적 열특성 분석 방법을 통하여 유리직물/나일론 6 복합재료의 층간전단강도 및 저장탄성률에 미치는 결합체 농도의 영향을 각각 조사하였다. CTMS 결합제의 농도가 증가할수록 복합재료의 계면특성이 향상되었다. 결합제의 농도 변화에 대한 유리섬유강화 나일론 6 복합재료의 계면전단강도, 층간전단강도, 층간파단양상 그리고 저장탄성률 등 각 특성 변화의 경향이 서로 일치하였다. In this work, glass fiber/nylon 6 and woven glass fiber/nylon 6 composites have been fabricated using glass fiber reinforcements sized with 3-chloropropyltrimethoxysilane(CTMS) having a chloropropyl organo-functional group in the molecular chain end. The interfacial shear strength of glass fiber/nylon 6 composite was measured using a single fiber microbonding test and the interlaminar shear strength and the storage modulus of woven glass fabric/nylon 6 composites were measured using a short-warn shear test and a dynamic mechanical analysis, respectively, informing the effect of the concentration of CTMS on the properties. With increasing CTMS concentration, the interfacial properties of the composites were improved. The results on the interfacial shear strength, interlaminar shear strength, interlaminar failure pattern, and storage modulus with varying the CTMS concentration agree with each other.

지중 박스 구조물 굴착시 침하형상에 대한 연구

조동환(Donghwan Cho),오정호(Jeongho Oh),박준경(Junkyung Park),김현기(HyunKi Kim) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05

기존의 원형터널은 터널굴착으로 인한 지표침하량 예측을 위한 다양한 경험식이 제안되어, 이를 활용한 침하영향범위산정 및 이완영역을 사전에 평가할 수 있는 지표로 활용되고 있다. 그러나, 지중박스구조물 굴착시 침하형상에 대한 연구는 미진한 실정으로, 본 연구에서는 2차원 유한요소해석을 이용하여 구형단면 터널에 대한 침하형상곡선에 대한 연구를 수행하였다. 매개변수분석을 통해 지하수위조건, 토피고, 터널단면형상, 시공조건등의 변화시 지표침하거동을 분석하여 기존 경험식의 적용가능성을 검토하고, 수치해석 결과를 바탕으로 지중박스구조물 굴착시 적용가능한 침하형상곡선식을 제안하였다. Various empirical equations have been proposed to predict the ground settlement profile due to excavation of conventional circular tunnels, and used to estimate the settlement influential range along with evaluate the relaxation area in advance. However, the study on ground movements for the underground box strurtures has not been fully studied. In this study, the ground settlement induced from underground box excavations is investigated using the two dimensional finite element analyses. A formulation to assess the settlement profile applicable to underground box structure is proposed based on the parametric analyses by the changes of ground condition, geometric condition of structure, and construction conditions.

전문대학생의 NCS기초능력군과 진로준비행동과의 관계에 관한 연구 : 의사소통능력과 수리능력을 중심으로

성행남,조동환,Sung, Haengnam,Cho, Donghwan 디지털산업정보학회 2019 디지털산업정보학회논문지 Vol.15 No.2

The importance of the NCS(National Competitiveness Standards) is growing as the job market shrinks and more institutions require hiring based on NCS. Of the ten domains of NCS', the most relevant one with the performance of all tasks is basic capability group. The purpose of this study is to investigate the effect of college students' basic capability group(communication capability, mathematical capability) on their career preparation behavior. In this study, we set up a process model to comprehend the effect of college students' basic capability group on career preparation behavior based on social cognitive career theory. For research model testing, 561 questionnaires were used for empirical analysis through structural equations modeling. Empirical analysis showed that communication capability positively influenced college students' career preparation behaviors for employment. But, mathematical capability don't influenced college students' career preparation behaviors for employment. Next, career self-efficacy and career outcome expectation each positively influenced college students' career preparation behaviors for employment. Also, interest in the major positively influenced college students' career preparation behaviors for employment. The academic implications are as follows: Career self-efficacy and interest in the major were important factors in the communication capability. The process of communication capability affecting career preparation behavior and interest in the major was explained through social cognitive career theory and self-efficacy. The practical implications are as follows: Administrative assistance should be provided to improve the career self-efficacy of college students.

전자빔에 의해 경화된 유리섬유/Diepoxidized Polycardanol 복합재료의 인장, 동역학 및 마모 특성

천진실,조동환,Cheon, Jinsil,Cho, Donghwan 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.3

In the present study, the effect of electron beam irradiation on the tensile, dynamic mechanical, and abrasion properties of glass-fiber-reinforced diepoxidized polycardanol (DEPC) composites was explored. Triarylsulfonium hexafluoroantimonate, an antimonate-type photoinitiator (2 wt%) was added to diepoxidized cardanol (DEC) prior to composite curing by electron beam. The glass fabrics pre-impregnated with DEPC were consolidated by direct irradiation of electron beam at 400, 500, and 600 kGy at ambient temperature and pressure. The composite properties strongly depend on the applied electron beam intensity. The result indicates that electron beam curing of glass fiber/DEPC composites at 600 kGy resulted in the highest tensile modulus, tensile strength, dynamic storage modulus, abrasion resistance, and lowest damping among the applied electron beam absorption doses.

전자선 조사를 통해 제조한 카복시메틸셀룰로스 수화젤의 팽윤거동

김민희,조동환,권오형,박원호,Kim, Min Hee,Cho, Donghwan,Kwon, Oh Hyeong,Park, Won Ho 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.6

In this study, carboxymethylcellulose (CMC) hydrogels were successfully prepared by electron beam irradiation. The morphology and mechanical properties of the hydrogels were examined by scanning electron microscopy and tensile testing, which indicated that the compressive strength of the hydrogels was closely associated with their pore wall thickness. In addition, the equilibrium swelling ratio of the hydrogels was evaluated in both distilled water and different physiological media, which indicated that their maximum swelling ratio was higher in water than that in physiological media. Moreover, their maximum swelling ratio decreased with an increase in salt concentration. The fabricated cellulose-based hydrogels were shown to be promising for applications in drug delivery systems and the field of biomaterials.

Norbornene 기능화 MWNT 제조 및 DCPD와의 나노복합재료

노흔효,양광,조동환,이종근,No, Heun Hyo,Yang, Guang,Cho, Donghwan,Lee, Jong Keun 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.3

Multi-walled carbon nanotubes (MWNT) were grafted with norbornene groups (MWNT-g-Norbornene) and incorporated into dicyclopentadiene (DCPD) to produce a nanocomposite cured by ring-opening metathesis polymerization (ROMP). The functionalization of the MWNT surfaces during the modification procedure was confirmed by means of FT-IR spectroscopy. Tensile test results showed that the toughness of the DCPD/MWNT-g-Norbornene nanocomposites was considerably increased by about 220%, compared to that of neat DCPD. The enhanced toughness could be a result of increased dispersion of MWNT-g-Norbornene and increased interfacial adhesion between the functionalized MWNT and DCPD, as revealed by FE-SEM images of the fractured surfaces.

크림프가 없는 탄소섬유직물/에폭시 복합재료의 동역학, 인장, 굴곡 및 충격 특성에 미치는 프리프레그 Angle-Ply의 영향

정나은(Naeun Jeong),조동환(Donghwan Cho) 한국고분자학회 2020 폴리머 Vol.44 No.1

일방향(UD) 프리프레그는 섬유방향으로 이방성을 띠고 있기 때문에 탄소섬유의 배향각은 탄소섬유/에폭시 복합재료의 기계적, 열적 특성에 중요한 역할을 한다. [0°], [0°/90°], [0°/45°/90°], [0°/30°/60°/90°] 적층 순서에 따라 서로 다른 angle-ply를 갖는 크림프가 없는 탄소섬유직물/에폭시 복합재료를 압축성형으로 제조하고, 그들의 특성에 미치는 프리프레그 angle-ply 영향을 조사하였다. [0°] 복합재료는 가장 높은 동역학적, 인장, 굴곡 및 충격 특성을 나타낸 반면, [90°] 복합재료는 가장 낮은 특성을 나타냈다. [0°/90°], [0°/45°/90°], [0°/30°/60°/90°] 복합재료는 프리프레그 angle-ply에 따라 [0°]와 [90°] 복합재료 사이의 특성을 나타내었다. 본 연구는 크림프가 없는 탄소섬유직물강화 복합재료의 특성 제어를 위해 프리프레그 angle-ply 디자인이 중요함을 가리킨다. Since unidirectional (UD) prepregs are anisotropic in the fiber alignment direction, the alignment angle of carbon fibers plays a significant role in the mechanical and thermal properties of carbon fiber/epoxy composites. Non-crimp carbon fiber fabric/epoxy composites with different angle-plies of [0°], [0°/90°], [0°/45°/90°], and [0°/30°/60°/90°] stacking sequences were prepared by compression molding. The effect of prepreg angle-ply on the properties of resulting composites was explored. The [0°] composite exhibited the highest dynamic mechanical, tensile, flexural and impact properties, whereas the [90°] composite exhibited the lowest properties. The properties of the [0°/90°], [0°/45°/90°], and [0°/30°/60°/90°] composites were intermediate between the [0°] and [90°] composites, depending on the angle-plies consisting of the composites. The present study indicates that prepreg angle-ply design should be importantly considered to manipulate their properties of non-crimp carbon fiber fabric-reinforced composites.

자기장에 의한 분쇄형 탄소섬유/Endo-Dicyclopentadiene 복합체의 열전도도 향상

박성민(Sung Min Park),조동환(Donghwan Cho),이종근(Jong Keun Lee) 한국고분자학회 2017 폴리머 Vol.41 No.6

분쇄형 탄소섬유(MCF)를 함유한 열전도성 고분자복합체를 제조한 후 열전도도를 측정하였고 매트릭스 내에 분포되어 있는 MCF를 관찰하였다. 매트릭스 수지로는 endo-dicyclopentadiene(endo-DCPD)를 사용하였으며, 수지경화반응 초기에 자기밀도가 0.47 Tesla인 영구자석으로 자기장을 인가하여 MCF를 자기장 방향으로 배열하였다. 수지 내에 소량의 산화철(III)을 첨가하여 인가된 자기장에 의하여 발생되는 액상 수지의 흐름에 통하여 MCF를 배열하였다. 자기장을 인가하지 않은 복합체와 비교하였을 때 8 vol% MCF 함량에서 열전도도가 약 210% 가량 크게 향상되었다. 이러한 향상효과는 자기장 방향으로 MCF의 배열에 기인한 것이며, MCF 배열현상을 광학현미경 관찰을 통해 규명하였다. 본 연구결과는 다른 연구에 비해 영구자석을 사용하여 낮은 자기력에서 매우 간단하면서도 효과적으로 복합체에 높은 열전도도를 부여할 수 있음을 제시하여 준다. Thermally conductive polymer composites containing milled carbon fibers (MCF) were prepared and the thermal conductivities and the MCF distribution in the matrix were observed. Endo-dicyclopentadiene (endo-DCPD) was used as matrix resin. The MCF was aligned along the direction of the magnetic field applied using a permanent magnet having a magnetic flux density of 0.47 Tesla at the beginning of the curing reaction. The MCF alignment was induced by the resin flow generated by a small amount of iron oxide (III) in the resin. The thermal conductivity was markedly enhanced by 210% at 8 vol% MCF, compared to the unaligned composite without a magnetic field. Such the remarkable enhancement was due to the MCF alignment in the magnetic field direction, as elucidated by optical microscopy. It suggests that high thermal conductivity can be imparted to a composite simply and effectively at low magnetic force using a permanent magnet, as compared to other studies.

플라즈마 표면처리에 의한 Silk/PLA 바이오복합재료의 계면접착

추보영,권미연,이승구,조동환,박원호,한성옥,Chu, Bo Young,Kwon, Mi Yeon,Lee, Seung Goo,Cho, Donghwan,Park, Won Ho,Han, Seong Ok 한국접착및계면학회 2004 접착 및 계면 Vol.5 No.4

견섬유와 폴리라틱산(PLA) 사이의 계면접착 특성을 향상시키기 위하여 천연섬유 표면을 아르곤과 에틸렌 플라즈마로 각각 처리하였다. 플라즈마 표면처리 후, 견섬유의 표면 모폴로지와 접착이 크게 변화하였다. 다음의 여러 플라즈마 처리조건이 본 연구에 사용되었다: 10, 25, 50 그리고 150 W의 전력, 1, 3, 5, 7 그리고 10분의 처리시간 및 10과 50 sccm의 가스흐름속도, 플라즈마 처리된 Silk/PLA 바이오복합재료의 계면전단강도는 단섬유 micro-droplet debonding 시험방법으로 측정하였다. 결과는 Silk/PLA 바이오복합재료의 계면접착을 향상시키기 위한 최적의 플라즈마 처리 조건을 제공하여 주었다. Silk fibers were subjected to argon and ethylene plasma treatments in order to improve the interfacial adhesion with polylactic acid (PLA). After the plasma surface treatment, the surface morphology and surface adhesion of silk fibers to the PLA resin were largely changed. Various plasma treatment conditions were used in this work: 10, 25, 50, 100 and 150 W of electric power, 1, 3, 5, 7 and 10 minutes of treatment time, and 10 and 50 sccm of a gas flow rate. The interfacial shear strength of plasma-treated Silk/PLA biocomposites was measured by a single fiber micro-droplet debonding test method. The result provided an optimal plasma treatment condition to obtain the improved interfacial adhesion in the Silk/PLA biocomposites.