반자율주행 맥락에서 AI 에이전트의 멀티모달 인터랙션이 운전자 경험에 미치는 효과

서민수(Min-soo Suh),홍승혜(Seung-Hye Hong),이정명(Jeong-Myeong Lee) 한국콘텐츠학회 2018 한국콘텐츠학회논문지 Vol.18 No.8

대화형 AI 스피커가 보편화되면서 음성인식은 자율주행 상황에서의 중요한 차량-운전자 인터랙션 방식으로 인식되고 있다. 이 연구의 목적은 반자율주행 상황에서 음성뿐만 아니라 AI 캐릭터의 시각적 피드백을 함께 전달하는 멀티모달 인터랙션이 음성 단일 모드 인터랙션보다 사용자 경험 최적화에 효과적인지를 확인하는 것이다. 실험 참가자에게 주행 중 AI 스피커와 캐릭터를 통해 음악 선곡과 조정을 위한 인터랙션 태스크를 수행하게 하고, 정보 및 시스템 품질, 실재감, 지각된 유용성과 용이성, 그리고 지속 사용 의도를 측정하였다. 평균차이 분석 결과, 대부분의 사용자 경험 요인에서 시각적 캐릭터의 멀티모달 효과는 나타나지 않았으며, 지속사용 의도에서도 효과는 나타나지 않았다. 오히려, 정보품질 요인에서 음성 단일 모드가 멀티모달보다 효과적인 것으로 나타났다. 운전자의 인지적 노력이 필요한 반자율주행 단계에서는 멀티모달 인터랙션이 단일 모드 인터랙션에 비해 사용자 경험 최적화에 효과적이지 않았다. As the interactive AI speaker becomes popular, voice recognition is regarded as an important vehicle-driver interaction method in case of autonomous driving situation. The purpose of this study is to confirm whether multimodal interaction in which feedback is transmitted by auditory and visual mode of AI characters on screen is more effective in user experience optimization than auditory mode only. We performed the interaction tasks for the music selection and adjustment through the AI speaker while driving to the experiment participant and measured the information and system quality, presence, the perceived usefulness and ease of use, and the continuance intention. As a result of analysis, the multimodal effect of visual characters was not shown in most user experience factors, and the effect was not shown in the intention of continuous use. Rather, it was found that auditory single mode was more effective than multimodal in information quality factor. In the semi-autonomous driving stage, which requires driver s cognitive effort, multimodal interaction is not effective in optimizing user experience as compared to single mode interaction.

Carbon Neutral Vessel Propulsion Technology for Implementing Net-zero Reliability

Min-Soo Suh(서민수),Kee Joo Kim(김기주) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

Inception of cutting surlphur oxide emission, the new limit was made compulsory following an amendment to Annex VI of the international convention for the prevention of pollution from ships. The International Maritime Organization (IMO), a significant reduction from the previous limit of 3.5% known as IMO 2020, the rule limits the sulphur in the fuel oil used on board ships operating outside designated emission control areas to 0.50% m/m (mass by mass). Within specific designated emission control areas the limits were already stricter (0.10%). Sulphur oxide (SOx) emissions from ships, the resulting reduction, is having major environmental benefits for the world, particularly for health of populations living close to ports and coasts. SOX can lead to acid rain, once released in the atmosphere, which impacts crops, forests and aquatic species and contributes to the acidification of the oceans. It is also harmful to human health, causing respiratory, cardiovascular and lung disease. Alkali-metal based energy transforming technology, the working principle is ionization of element and vibration of phonons, is clean and high efficiency with zero emission. According to SERI report, AMTEC is known as the highest efficiency among most of other thermally regenerative electrochemical cells (TRES). Electrochemical cells are core component where the dominant reaction occurred in and working substance are produced for fuel cell, battery, galvanic cell, electromotive force cell and thermocell. Under the principle of electrochemistry, thermal-to-electric is the dominant process in the sense of an energy conversion and the electrical-to-chemical is dominant in the sense of an energy storage. AMTEC is a thermodynamically closed system that converts thermal energy into electric energy. It is an electrochemical heat engine that is Carnot cycle limited in efficiency, and a great part of output involve in electricity. Transforming energy in TRES involves energy transport, energy conversion and energy storage. This study is to report the effort to develop ecofriendly vessel propulsion as dual fuel direct conversion (DFDC) utilizing AMTEC technology for vessel propulsion in order to contribute net-zero carbon-neutrality.

알칼리금속 열전기변환장치의 접합과 출력성능

서민수(Min-Soo Suh),이욱현(Wook-Hyun Lee),우상국(Sang-Kuk Woo) 대한기계학회 2017 大韓機械學會論文集A Vol.41 No.7

알칼리금속을 이용한 열전기변환장치(Alkali-Metal Thermal-to-electric Converter)는 열을 전기로 직접 변환하는 기술이다. AMTEC 기술은 기존 에너지기술 대비 고효율성과 고밀도성을 지니는 정적 에너지 변환 장치로서 이론 발전효율이 40%로 높고 단위발전량이 500 W/kg, 2.01 W/cm2로 우수하다. AMTEC의 작동원리는 작동유체인 소듐이 분압차이에 의해서 고체전해질인 베타알루미나(BASE)의 내부에서 외부로 이온화를 거쳐며 통과하는데, 이때 전자를 주고 받으며 전기를 생성한다. BASE내외부의 분압차 형성을 위해서는 고온내구성과 기밀성이 높은 접합기술이 요구된다. 개발된 접합기술을 이용하여BASE/절연부/금속부 시스템의 안정적인 전기적/구조적 시스템을 구성하고 멀티-셀 모듈들을 제작하여 개방회로 전압과 전류-전압특성을 측정하는 방법으로 AMTEC 모듈전지들의 출력성능과 수명을 평가하였다. The alkali-Metal Thermal-to-electric Converter (AMTEC) is one of the promising static energy conversion technologies for the direct conversion of thermal energy to electrical energy. The advantages over a conventional energy converter are its high theoretical conversion efficiency of 40% and power density of 500 W/kg. The working principle of an AMTEC battery is the electrochemical reaction of the sodium through an ion conducting electrolyte. Sodium ion pass through the hot side of the beta”-alumina solid electrolyte (BASE) primarily as a result of the pressure difference. This pressure difference across the BASE has a significant effect on the overall performance of the AMTEC system. In order to build the high pressure difference across the BASE, hermeticity is required for each joined components for high temperature range of 900°C. The AMTEC battery was manufactured by utilizing robust joining technology of BASE/insulator/metal flange interfaces of the system for both structural and electrical stability. The electrical potential difference between the anode and cathode sides, where the electrons emitted from sodium ionization and recombined into sodium, was characterized as the open-circuit voltage. The efforts of technological improvement were concentrated on a high-power output and conversion efficiency. This paper discusses about the joining and performance of the AMTEC systems.

Reliability Evaluation of Alkali-Metal based Heat Pipe and TEC (Thermal-to-Electric Convertor)

Min-Soo SUH(서민수) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

In thermodynamics, enthalpy is defined as the sum of the system’s internal energy and the product of its pressure and volume. It could be a state function standardly used in many measurements in various fields e.g., chemical, biological and physical systems at a constant pressure. The work required to establish the physical dimension of system could be expressed by pressure-volume term. As a state, function, enthalpy depends only on the final configuration of internal energy, pressure and volume, not on the path taken to achieve it. The unit of measurement for enthalpy is joule as the international standards and calorie as the British thermal unit. In chemistry, the standard enthalpy of reaction is the enthalpy change when reactants in their standard states as 1 bar pressure and 298 K temperature change to products in their standard states. (Thermodynamics: H = E + pV , Electrochemistry: H = U + pT) Na-AMTEC directly convert thermal energy into electrical energy, in specific terms, the static energy conversion subjected to electrochemical reaction mainly dependent to its chemical kinetics and temperature is differed from the dynamic energy conversion where system’s internal energy mainly dependent to its pressure and volume via mechanical motion. Particularly in Na-AMTEC, direct conversion of thermal energy into electrical energy is transpired via ionization of natrium as known as reduction and oxidation (REDOX). In specific terms, by input of thermal energy the static energy conversion 1) ionization of natrium occurred on anodic electrode, 2) divided electron flow on the circuit to do the electrical work, 3) temperature difference between region of the thermal energy input (source, evaporation regime) and the thermal energy output (sink, condensation regime) generates electrical energy as work. The efficiency of Na-AMTEC could be derived as following and these heat engines distinguish themselves from another types of engines by the fact that their efficiency is fundamentally limited by Carnot’s theorem. Efficiency is defined as the difference of high temperature state, T_H and low temperature state, T_L over T_H. ● Carnot efficiency = (T_H - T_L) / TL, e.g. (1000 K – 500 K) / 500 K = 50% ● Na-AMTEC efficiency = Electrical energy output, W_e / Thermal energy input, W_th =Vi / (electricity output + heating of natrium + heat to vaporize natrium) = 46.8% at T_H, T_Lsame as above condition (1000 K and 500 K) Therefore, the efficiency of Na-AMTEC is approaching near the Carnot efficiency about 93.4%, which could be possible to overcome the 75% efficiency of Carnot efficiency as known as endoreversible thermodynamics. In case of thermal energy in both of Na heat pipe and Na-AMTEC, the liquid-metal is an energy medium of heat transfer (HF) and heat transfer fluid (HTF). Especially, Na alkali-metal is transporting thermal energy from one regime to another. The purpose of Na heat pipe is transferring thermal energy from source to sink with maximizing heat transfer rate and minimizing the heat loss to ambient surroundings. Similarly, the purpose of Na-AMTEC as known as alkali-metal based thermopower heat pipe is to convert thermal source directly into electricity in order to reduce the energy loss during the conversion processes e.g. thermal energy loss during phase change of HTF, energy loss in terms of temperature and pressure during the energy transportation and energy loss during relative mechanical motion results from energy loss due to friction and materials squander due to wear. In microscopic view, the Na HTF evaporated from liquid-to-gaseous state and liquified at condensing regime. In macroscopic view, the natrium as working fluid ionized into Na⁺ cation and electron in terms of REDOX electrochemistry principle, which is governed by Nernst’s theorem. This study is to report the develo

금속-세라믹간 이종접합과 접합강도

서민수(Min-Soo Suh),김세영(Se Young Kim),김선동(Sun-Dong Kim),우상국(Sang-Kuk Woo) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.4-1

Electrical Resistance Evaluation Reliability under High Grade Temperature for Na-AMTEC(Natrium Alkali-Metal Thermal-to-Electric Convertor)

Min-Soo SUH(서민수) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

In general, an electrical circuit, electrical resistance is a measure of the opposition to current flow. Resistance is a measured in ohms, symbolized by the Greek letter omega(Ω). In practical, specialized on Na-AMTEC(Natrium Alkali-Metal Thermal-to-Electric Convertor), the input energy is directly converted to electrical energy. In microscopic view, the energy transforming of one source to another useful forms classified as storage, transportation and conversion is simultaneous taken place in one small circuit. In macroscopic view, thermal energy directly converted into electrical energy, in other words it is energy transforming primarily solar-to-thermal and thermal-to-electric. In case of metallic substances, free electrons are moving randomly in the crystal structure of it. Due mainly to the electric field across the resistance, free electrons drift from lower potential point to higher potential when voltage is applied. Free electron continually collides with atoms of the substance during drifting motion, this phenomenon prevents the free motion of electrons. The resistance is known to be caused by the collision of free electron with atoms of the substance. Physicist George Simon Ohm suggest the law ohm that electric resistance is equal to voltage per ampere on pure metal. Hence, resistance is defined as the ratio of the applied voltage to the current through the substance. Most of metallic substance with rising temperatures the inter atomic vibrations increase and consequently offer more resistance to the movement of electrons causing the current. Thus, with increasing temperature the resistance of metallic substances increases. Refractory metals are a class of metals that are extraordinarily resistant to heat. The well-known Na-AMTEC is working between 800 K to 1300 K. Most of materials does not meet the criteria of aforementioned working condition in sense of thermo-condition except the five elements two of fifth period (niobium and molybdenum) and three of the sixth period (tantalum, tungsten and rhenium). They all share some properties, including a melting point above 2,200 K and high hardness at room temperature, except ductile transition character of niobium. Pure niobium has a Mohs hardness rating similar to that of pure titanium. Hence, the selection of candidate materials for Na-AMTEC as electrical electrode, current collector and lead is narrowed down to the minimum requirement of temperature resistance and electrical conductivity. In case of electrical resistance of Na-AMTEC is derived as following that the total resistance, R_T of Na-AMTEC is sum of the following resistances R_B (Resistance of Beta-Alumina Solid Electrolyte, BASE) + R_S (sheet resistance) + R_C (contact resistance) + R_L (lead resistance). Mostly, the sum of the rest of resistances is larger than the resistance of BASE. ● Correlation of Voltage, Ampere and Resistance: V ∝ I , V = RI , R= V/I ● Total electrical resistance of Na-AMTEC: R_T = R_B + R_S + R_C + R_L, R_B < R_S + R_C + R_L ● Correlation of resistances of Na-AMTEC: R_T ∝ 2 R_B Nonetheless, there is a reliability issue when measuring the electrical resistance which is intricate compared to the concept of electrical conductivity measurement on room temperature by virtue of the continuous temperature deviation during the Na-AMTEC cell test under elevated temperature. This study is to report the effort to develop the methodology of measurement reliability of the electrical resistance under high temperature state.

알칼리금속 열전기변환장치의 접합과 출력성능

서민수(Min-Soo Suh),김선동(Sun-Dong Kim),이욱현(Wook-Hyun Lee),우상국(Sang-Kuk Woo) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.4

Electrical Power and Material Characterization under High Grade Temperature for Na-AMTEC(Natrium Alkali-Metal Thermal-to-Electric Convertor)

Min-Soo SUH(서민수),Dae Hun CHUNG(정대헌) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.06

R&D Insight of Convergence Technology Aiming for Carbon-Neutrality

Min-Soo SUH(서민수),Kotaro TANAKA(田中耕太朗) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.06

SiC 단체와 SiC/SiC 복합재료의 충격파괴거동

서민수(Min-Soo Suh),서창민(Chang-Min Suh) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.2