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Effects of Workplace Fun on Employee Behaviors: Focused on Generation Y in the Hospitality Industry
No full textThe conceptual model of this study was tested based on responses from 234 hospitality students in the US who are Generation Yers and had worked in the hospitality industry for more than 3 months. This study revealed that Generation Y employees’ attitude toward workplace fun positively affects their experienced workplace fun. In turn, Generation Yers’ experienced workplace fun showed direct effects on their job satisfaction, task performance, and interpersonal citizenship behaviors. Affected by experienced workplace fun, job satisfaction significantly enhanced employees’ task performance and interpersonal job satisfaction. In essence, for Generation Y employees in hospitality businesses, workplace fun is a significant factor in their job satisfaction, task performance, and interpersonal citizenship behavior. These findings provide a significant insight to hospitality employers who typically have a hard time to attract best young talents and motivate them mainly due to low-paying, low-status nature of hospitality jobs
An Online Method to Detect and Locate an External Load on the Human Body with Applications in Ergonomics Assessment
No full textIn this work, we propose an online method to detect and approximately locate an external load induced on the body of a person interacting with the environment. The method is based on a torque equilibrium condition on the human sagittal plane, which takes into account a reduced-complexity model of the whole-body centre of pressure (CoP) along with the measured one, and the vertical component of the ground reaction forces (vGRFs). The latter is combined with a statistical analysis approach to improve the localisation accuracy, (which is subject to uncertainties) to the extent of the industrial applications we target. The proposed technique eliminates the assumption of known contact position of an external load on the human limbs, allowing a more flexible online body-state tracking. The accuracy of the proposed method is first evaluated via a simulation study in which various contact points on different body postures are considered. Next, experiments on human subjects with three different contact locations applied to the human body are presented, revealing the validity of the proposed methodology. Lastly, its benefit in the estimation of human dynamic states is demonstrated. These results add another layer to the online human ergonomics assessment framework developed in our laboratory, extending it to more realistic and varying interaction conditions
ErgoTac: A Tactile Feedback Interface for Improving Human Ergonomics in Workplaces
No full textIn this letter, we present a novel wearable feedback interface with the aim to improve human ergonomics in the execution of heavy or repetitive industrial tasks. The proposed interface incorporates a reduced-complexity and real-time model for the estimation of human joints’ load variations, based on the estimated translational displacement of the center of pressure in the presence of external forces and loads. Wireless vibrotactile displays are then developed to inform humans about excessive overloading of body joints by applying appropriate tactile stimuli, and to guide them towards more ergonomic and suitable physical loading conditions. We validated our framework by a user study during which the subjects while performing a heavy object lifting task, reconfigured the body pose to minimize the overloading efforts. This was achieved by following the vibrotactile feedback guidance, provided by wearable tactile devices. Experimental results include a statistical analysis of ten subjects that demonstrate the potential of the proposed method in assisting human workers. The integration of such wearable devices in working environments can contribute to the improvement of human ergonomics, due to the monitoring and reduction of physical overloadings
Towards Ergonomic Control of Collaborative Effort in Multi-human Mobile-robot Teams
No full textIn this paper, we propose a control framework for a multi-human and mobile-robot collaborative team, that takes into account the co-workers' ergonomic requirements as well as the demand for high flexibility in the manufacturing industries. The new MObile Collaborative robotic Assistant (MOCA), which is composed of a lightweight manipulator arm, an underactuated hand, and a mobile platform driven by four omni-directional wheels enabling mobility in the workspace, is able to accomplish multiple tasks in a wide area with a high level of adaptability. In addition, an ergonomics module to anticipate and mitigate the human risk factors by means of a multi-object optimisation is integrated into the framework to ensure human safety and improvement of working conditions. The main advantage of this approach is that MOCA can assist multiple human operators, reducing their physical risks, with fast-adaptive capacities due to agile mobility and advanced interaction and manipulation. We validated the proposed method with an experiment simulating a simple manufacturing line which involves two subjects and the MOCA. The results demonstrate that the proposed framework is able to address multi-workers' ergonomics with a high level of flexibility in the workplace
Toward a Synergistic Framework for Human-Robot Coexistence and Collaboration (HRC2 )
No full textThis paper presents a proof of concept for a synergistic framework for human-robot coexistence and collaboration (HRC 2). By exploiting the loco-manipulation potential of our recently developed MObile Collaborative robotic Assistant (MOCA), we developed a novel framework that distinguishes and suitably reacts to coexisting and collaborative human partners. The framework avoids any collisions or physical contacts with coexisting partners while enabling ergonomic physical interactions with the collaborative-identified ones. The selection of the collaborative partners is achieved through body gestures
ErgoTac-Belt: Anticipatory Vibrotactile Feedback to Lead Centre of Pressure during Walking
No full textBalance and gait disorders are the second leading cause of falls, which, along with consequent injuries, are reported as major public health problems all over the world. For patients who do not require mechanical support, vibrotactile feedback interfaces have proven to be a successful approach in restoring balance. Most of the existing strategies assess trunk or head tilt and velocity or plantar forces, and are limited to the analysis of stance. On the other hand, central to balance control is the need to maintain the body's centre of pressure (CoP) within feasible limits of the support polygon (SP), as in standing, or on track to a new SP, as in walking. Hence, this paper proposes an exploratory study to investigate whether vibrotactile feedback can be employed to lead human CoP during walking. The ErgoTac-Belt vibrotactile device is introduced to instruct the users about the direction to take, both in the antero-posterior and medio-lateral axes. An anticipatory strategy is adopted here, to give the users enough time to react to the stimuli. Experiments on ten healthy subjects demonstrated the promising capability of the proposed device to guide the users' CoP along a predefined reference path, with similar performance as the one achieved with visual feedback. Future developments will investigate our strategy and device in guiding the CoP of elderly or individuals with vestibular impairments, who may not be aware of or, able to figure out, a safe and ergonomic CoP path
A Soft Assistive Device for Elbow Effort-Compensation
No full textThe use of assistive technologies in industrial
environments to improve human ergonomics and comfort in
repetitive and high effort tasks have increased considerably
in the last decade. Predominantly, the goal is to provide
additional physical support through lightweight and wearable
devices, without posing major constraints to the human body
movements. Towards achieving this objective, in this work we
present a novel actuation mechanism for a soft assistive device,
by taking into account the human elbow torque-angle profile.
The proposed design integrates a single motor coupled with
an elastic bungee and a cam-spool mechanism to enable energy
exchange during the elbow flexion movement, while allowing for
free-motions during the extension of the joint. A cable-driven
transmission with passive elastic attachments is employed to
implement compliant couplings with the wearer and to achieve
easy donning/doffing. Experiments are conducted on two 3D
printed functional prototypes. Results suggest that the assistive
elbow torque is effectively transmitted with an average 90%
success for balancing a 5N payload, and the free-motion range
of 108 degree is measured for both flexion and extension
Audio Search Interface Using Touch Sensitive Sliders
No full text학위논문 (석사)-- 서울대학교 대학원 : 융합과학기술대학원 융합과학부, 2018. 2. 이교구.영화 음향 믹싱 엔지니어는 자신이 변형하려고 하는 효과음을 찾는데 많은 시간을 사용한다. 이는 제한된 시간에 콘텐츠를 만들어야 하는 현재의 영화 제작 구조상 음향 믹싱 엔지니어를 제약한다. 이를 해결하기 위해 음향 믹싱 과정에서 사용하는 음향 콘솔에 트랙별로 음원을 더 잘 시각화해주는 발전이 있었지만 매우 많은 수의 트랙을 사용하는 영화 음향 믹싱 엔지니어를 돕기에는 한계가 있다.
한편, 영화 음향 믹싱 엔지니어를 돕기 위한 연구는 아니지만 목소리, 태핑, 몸 움직임 등 각종 질의(query)를 통한 효과음 검색 연구가 진행되어 왔다. 또한 효과음에서 추출한 소리 크기 변화 곡선, 음 높이 변화 곡선 등과 같은 음향 특성과 사람에게 효과음을 들려주며 몸의 움직임을 사용해서 표현하도록 지시해서 얻은 움직임 데이터를 비교해서 그 연관성을 찾기 위한 소리 투사 연구도 이루어지고 있다.
본 연구는 터치 슬라이더를 이용한 소리 투사 연구를 진행하고 이를 활용해서 영화 음향 믹싱 엔지니어들이 효과음 검색에 사용 가능한 인터페이스를 개발하고 그 사용성을 평가하는 것을 목표로 한다.제 1 장 서론 1
제 1 절 연구 배경 1
제 2 절 연구 목표 8
제 2 장 선행 연구 및 관련 개념 9
제 1 절 음향 콘솔에서 소리 탐색 연구 9
제 2 절 질의 기반 소리 검색 연구 15
제 3 절 소리 투사 연구 17
제 4 절 터치 슬라이더 19
제 3 장 연구 방법 및 제안 특성 21
제 1 절 연구 문제 21
제 2 절 제안 특성 23
3.2.1 제안 음향 특성 23
3.2.2 제안 움직임 특성 25
제 3 절 소리 투사 실험 26
3.3.1 효과음 데이터 26
3.3.2 소리 투사 실험 29
3.3.3 소리 투사 데이터 처리 31
제 4 절 소리 투사 모델 32
제 4 장 제안 인터페이스 35
제 1 절 인터페이스 개요 35
4.1.1 검색 인터페이스 개요 35
4.1.2 검색 알고리즘 개요 37
제 2 절 인터페이스 평가 39
4.2.1 인터페이스 평가 방법 39
4.2.2 정확도 평가 결과 46
4.2.3 사용성 평가 결과 47
제 5 장 연구 의의 및 논의 56
참고문헌 59
Abstract 62Maste
Multi-Metric Optimization for Human Walking
No full textWalking is an essential part of almost all activities of daily living. Depending on the situation, different gait patterns can be observed, e.g., moving around the house, performing different sports, or even in case of injury. Even though the gait has been analyzed thoroughly for many decades, there are still some unexplored aspects that require more insight, especially those related to the influence of various parameters on the optimality and diversity of gait patterns. Many gait trajectory optimization strategies have been proposed in literature, however, most of them focus merely on optimizing for one metric (e.g., energy efficiency or joint torque). In this study, a multi-metric gait optimization framework is proposed, simultaneously accounting for joint torque, fatigue, and manipulability. To that end, 45 gaits, varying in stride length, step height, and walking speed, were recorded in a motion capture experiment, together forming a solution space of dynamically stable and physiologically feasible gaits, for the proposed optimization framework. Specific user needs (gait requirements) can be accounted for by adjusting the optimization weights, after which brute-force optimization is applied to either analyze the gait within the collected subspace or select the optimal gait with respect to desired parameters. Results are presented for a baseline case (with all optimization weights set to one), which can be used as a tool for gait analysis, in particular giving insights into specific aspects of the gait, e.g., joint loading, long-term performance, and capacity to sustain ground reaction forces (GRFs).Mechanical Engineering | BioMechanical Desig
Substituents Effects on Properties of Perylene Dyes for Spectrum Conversion Film
No full text학위논문(석사) -- 서울대학교대학원 : 공과대학 재료공학부, 2022.2. 김재필.필름 상태에서 형광 퀜칭이 적게 일어나고, 적색 형광 광전환 필름에 사용하기에 적합한 염료를 개발하기 위해 부피가 다른 세 종의 치환체를 퍼릴렌 염료의 bay 위치에 도입하여 세 종의 염료를 합성했다. 합성된 세 염료의 광학적 특성과 형광 특성을 측정했고, 염료의 최적화된 구조, 분자의 오비탈 등을 Gaussian 16 프로그램의 DFT, TD-DFT를 통해 계산했으며, 공정 과정에서의 열 안정성을 알아보기 위하여 TGA를 통해 내열성을 측정했다. 도입한 치환체들의 부피가 커질수록 용액 상태에서 염료의 Stokes shift와 형광 양자 효율이 증가했고 이 원인에 대한 분석을 진행했다. Stokes shift의 증가는 각 염료의 S0 state 일 때와 S1 state 일 때의 구조의 차이를 계산함으로써 분석했다. 염료의 부피가 커질수록 분자 간 입체 장애가 증가하여 응집이 억제되었고, 응집에 의한 형광 퀜칭 (ACQ)이 억제되어 용액 상태에서 염료의 형광 양자 효율이 높아지는 경향을 보였으며, 이를 분자의 부피와 퀜칭상수 (kq) 계산을 통해 수치적으로 분석했다. 합성된 염료들의 용액 상태에서의 특성이 필름 상태에서도 유지되는지 알아보고, 필름 상태에서 염료들의 적색 투과 광전환 필름의 적합성을 알아보기 위하여 PMMA를 바인더로 이용하여 필름으로 제작했다. 필름 상태에서 합성된 세 염료의 광학적 특성과 형광 특성을 측정했고, 가장 좋은 특성을 보인 한 종의 염료 (PI-TBPO)를 적색 형광 광전환 필름으로 제작하여, 상추의 광합성 속도와 수확량을 측정했다. 이번 연구를 통하여 적색 형광 광전환 필름에 사용하기에 적합한 염료를 개발하였으며, 염료들의 광학적 특성과 형광 특성을 수치적으로 분석했다.We synthesized three dyes with less fluorescence quenching suitable for red fluorescence spectrum conversion film (SCF) by introducing substituents with different volumes at the bay positions of the perylene dye. The photophysical properties, optimized structures, and energy states of the synthesized dyes were investigated by experiments and computational calculations (DFT/B3LYP/6-31G, Gaussian 16 program package). Also, the thermal stability of the dyes was investigated by thermogravimetric analysis (TGA). The Stokes shift and fluorescence quantum yields of the dyes in the solution state increased as the volume of the bay position-substituents increased. We compared the Stokes shift of each dye by comparing the structural difference between S0 and S1 states of each compound. Also, we investigated the quenching constant (kq) and molar volume of the dyes in the solution state to verify the relation between the degree of intermolecular steric hindrance and the degree of aggregation caused quenching (ACQ). PMMA films doped with the synthesized dyes were fabricated, and the photophysical properties were investigated. The photosynthesis rate and growth of the lettuce were measured by the film doped with PI-TBPO, which shows the best properties among the dyes.초록 i
목차 iv
[Figure List] vii
[Table List] viii
[Scheme List] ix
1. 서론 1
1.1 농업 생산량 증가를 위한 광전환 필름 1
1.2 광전환 필름용 염료 2
1.3 Perylene 계 염료 3
2. 실험방법 6
2.1 시약 및 장비 6
2.1.1 시약 6
2.1.2 장비 6
2.2 물질의 합성 및 구조 분석 8
2.2.1 PDA-Cl4의 합성 8
2.2.2 PI-Phenoxy의 합성 9
2.2.3 PI-Cresol의 합성 11
2.2.4 PI-TBPO의 합성 13
2.3 필름 제작 14
2.4 염료 구조의 최적화 15
3. 실험결과 및 논의 15
3.1 분자 구조 디자인 및 구조 분석 15
3.1.1 분자 구조의 디자인 15
3.1.2 분자 구조의 분석 17
3.2 광학적 특성 분석 20
3.2.1 용액에서의 흡수, 발광 분석 20
3.2.1.1 Stokes Shift 분석 21
3.3 형광 특성 분석 25
3.3.1 Stern-Volmer 방정식을 통한 퀜칭상수 계산 26
3.4 필름 분석 29
3.4.1 필름 상태의 광학적 특성 분석 30
3.4.2 필름 상태의 형광 특성 분석 34
3.5 내열성 분석 35
3.6 식물 성장 37
4. 결론 및 요약 40
5. 참고 문헌 43
Abstract 48석
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