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There are various control laws for attitude stabilization and maneuvering such as magnetic torque control, solar torque control, momentum exchange control. Such controllers work in a linear continuous mode. But the torque that they can produce is in the range of 0.02– 1 N m for momentum exchange control, 10−2– 10 −3 N m for magnetic torque control, and 10−5– 10 −6 N m for solar torque control. Therefore, the speed of attitude maneuvering is limited by the low-level maximal torques that can be delivered to the attitude control system. Thruster control used in attitude control is no linear continuous reaction thrust control. However, they can provide almost any torque level. Their range between 0.01 N m and 30 N m , which is very common in most satellite. It is practical and convenient to use thruster for the rate damping control of small satellite during initial separation from launch vehicle. The paper deals with the analysis and design of thruster attitude control of a small satellite OptimSat. Simulation results shows that rate damping control for small satellite using thruster is effective.

One lidless CPU product failed more than 20% of visual inspections due to foreign material near the capacitor electrodes during testing production. This paper presents the analysis method for the foreign material, formation mechanism of dendrites, verification experiment by DOE, root cause for this case, and corrective solutions.

2, 4-Dinitrophenol (2, 4-DNP) is widely used in industry, but recently, poisoning through consumption for weight control has been frequently reported. We report the cases of two patients whose deaths were attributed to occupational and non-oral exposure of 2, 4-DNP. They were all poisoned through skin absorption and respiratory tract inhalation; common features were excessive sweating, hyperthermia, tachycardia, clouded consciousness and asystole. Because of the lack of specific early symptoms, effective antidotes and the means of washing the contamination from the skin, their arrival in hospital was delayed and the supportive therapy was ineffectual. Cardiac arrest occurred quickly and unexpected after admission.

It is introduced in this paper that a system of multi-point temperature measurement and control has been designed in advanced technology of computer and industrial control area for thermal discharge model test. Digital temperature sensors in “1-wire bus”, digital circuit modules, standardized products XFC components and functional circuit module are applied in hardware of the system. Object-oriented approach is adopted in software designing and programming. C++6.0 and AutoCAD are used in measurement procedures and data processing for easily operation and real time measurement. From a number of applications on model test study for water environment near power plants in the Yangtze River, it is shown that the measurement is satisfactorily precise and reliable, meeting the requirements of design and test. The practical system in advanced technology and related equipment can be used in any place where water temperature monitoring is possible and necessary, such as rivers, lakes, reservoirs, canals or swamp water environments.

To protect the environment, lead-free solder will be introduced in microelectronic products to replace lead solder. Proper lead-free bump removal is very important to the success of subsequent analysis steps. In this paper, a state-of-the-art wet etch recipe has been developed to remove Sn-Ag-Cu bumps. By optimizing the recipe, the resulting process has enabled the authors to identify defects within failing devices through front-side deprocessing.

The phase matching for second harmonic generation(SHG) in biaxial nonlinear-optical crystals is discussed and the accurate calculation of the corresponding effective nonlinear coefficients is presented, based on which the optimum phase matching can be determined. As an example, numerical treatment of phase matching and the corresponding effective nonlinear coefficients for SHG at fundamental wavelengths of 1.064μm and 0.808μm in the organic nonlinear-optical crystal benzophenone is performed, and accordingly the optimum phase matchings are found.

A transparent model alloy, succinonitrile-0.93wt.% salol is unidirectionally solidified under the accurately controled experimental conditions to investigate the selection of initial perturbation wavelength of a planar interface. The experimental data are compared with the Mullins-Sekerka (M-S) theory and the Warren-Langer (W-L) model. The following results are obtained: (1) Some experimental points do not lie within the wavelength range predicted by the M-S theory when Vcmsecms, where Ve is the pulling velocity, Vcms is the critical instability velocity of a planar interface given by M-S theory. When Ve》1.57Vcms, the experimental points are all within the wavelength range, but several times larger than the wavelength with the fastest amplitude developing speed predicted by the M-S theory. In short, the M-S theory cannot be used effectively to predict the selection of the initial perturbation wavelength of a planar interface. (2) The experimental results obtained in different alloys are all in good agreement with the W-L model, which proves that the initial perturbation of a planar interface is generated by the dramatic amplification of the ambient thermal micro-fluctuation with a characteristic wavelength.

Time-dependent development of interface morphology from initial perturbation of a planar interface to a steady periodic array of cells or dendrites was directly observed during directional solidification brocess of a transparent model alloy, succinonitrile -1.1 wt% ethanol. The following results are obtained: 1) The measured wavelength of initial perturbation of planar interface instability is within the expected wavelength range by the MS theory, but not the same as the expected wavelength with the fastest amplitude developing speed. 2) During the initial stage of a planar interface instability, the developing speed of perturbation amplitude is indeed a linear function of the amplitude, but the measured value of the amplitude developing rate is much smaller than the theoretical value. 3) The features of morphology development of cells and dendrites are different from each other, and the main cause leading to the different developing behaviour is that the relative scale of the steady primary spacing and the initial perturbation wavelength is different in the two cases.

In collaboration systems, collaborators often use hand gestures for showing information relating to a distant object. However, in viewer’s perspective, it is sometimes difficult to know where the conventional gesture cue (Hands-in-Air style: HiA) refers to because the conventional HiA gesture appears away from the distant object. In this paper, we investigate how two factors, distance to the object and view angle difference between collaborators, influence the understanding of HiA gesture by comparing the use of it at 25 positions with 5 distances and 5 view angles. In a user study, we found that the distance to the target object and view angle difference negatively influenced HiA gesture communication. The influence of the distance and view angle was more serious between smaller angles (0~30 degree) than larger angles (30~60 degree), and between shorter distances (1m $\sim 1.5\text{m}$ ) than between longer distance (1.5m $\sim 2\text{m}$ ). As a solution, we propose the Hands-on-Target (HoT) style which positions the hand gesture cue on the surface of the target object. The HoT style gesture cue dramatically reduces the negative effect of the distance and view angle difference. Participants completed the task 29.3 percent faster, selected the correct object 2.75 times more, and felt 63.1 percent less mental effort. For further investigation, we discuss on the extensibility of the HoT interface that it can be used not only for object selection but also for diverse type of gesture communication including gesture for object manipulation because the HoT interface can support all possible real world hand gestures.

Many systems have been developed to support remote guidance, where a local worker manipulates objects under guidance of a remote expert helper. These systems typically use speech and visual cues between the local worker and the remote helper, where the visual cues could be pointers, hand gestures, or sketches. However, the effects of combining visual cues together in remote collaboration has not been fully explored. We conducted a user study comparing remote collaboration with an interface that combined hand gestures and sketching (the HandsInTouch interface) to one that only used hand gestures, when solving two tasks; Lego assembly and repairing a laptop. In the user study, we found that (1) adding sketch cues improved the task completion time, only with the repairing task as this had complex object manipulation but (2) using gesture and sketching together created a higher task load for the user. Refereed/Peer-reviewed

Remote collaboration is becoming increasingly crucial, especially currently when travel is restricted because of the Covid-19 pandemic. People are looking for real-time and no-travel solutions to enable remote collaboration with colleagues and experts. A lot of research has been conducted on how to support remote guidance on physical tasks. However, these studies have mainly focused on development of technical components to support collaboration, while less attention has been paid into exploring and evaluating human factors that could influence remote collaboration. The aim of this paper is to identify human factors including culture, language, trust and social status for their possible effects on remote collaboration by reviewing their effects on computer-supported collaboration. This review adds more critical views of human perspectives into the current research mostly-focused on the technical side of remote guidance. Refereed/Peer-reviewed

We have proposed a proof of concept of a gaze window interface. A gaze window interface uses the user's gaze point to show the relevant content nearby the current gaze point. A system of a gaze window interface has been implemented that allows users to manage looking at multiple objects of interest on the screen while the system is responsive to the user's gaze points with relevant information shown in the gaze window. We also conducted user studies to investigate the effects of the interface on user performance and behaviors. In this paper, we report on a user study in which the gaze window was compared with a mouse window for supporting single user data entry tasks. We describe details of the study design and conduction and present the results. Refereed/Peer-reviewed

© 2019 Copyright held by the owner/author(s). Many researchers have studied various visual communication cues (e.g. pointer, sketching, and hand gesture) in Mixed Reality remote collaboration systems for real-world tasks. However, the effect of combining them has not been so well explored. We studied the effect of these cues in four combinations: hand only, hand + pointer, hand + sketch, and hand + pointer + sketch, with three problem tasks: Lego, Tangram, and Origami. The study results showed that the participants completed the task significantly faster and felt a significantly higher level of usability when the sketch cue is added to the hand gesture cue, but not with adding the pointer cue. Participants also preferred the combinations including hand and sketch cues over the other combinations. However, using additional cues (pointer or sketch) increased the perceived mental effort and did not improve the feeling of co-presence. We discuss the implications of these results and future research directions.

Many systems have been developed to support remote collaboration, where hand gestures or sketches can be shared. However, the effect of combining gesture and sketching together has not been fully explored and understood. In this paper we describe HandsInTouch, a system in which both hand gestures and sketches made by a remote helper are shown to a local user in real time. We conducted a user study to test the usability of the system and the usefulness of combing gesture and sketching for remote collaboration. We discuss results and make recommendations for system design and future work. Refereed/Peer-reviewed

Principal Component Analysis (PCA) is an established and efficient method for finding structure in a multidimensional data set. PCA is based on orthogonal transformations that convert a set of multidimensional values into linearly uncorrelated variables called principal components.The main disadvantage to the PCA approach is that the procedure and outcome are often difficult to understand. The connection between input and output can be puzzling, a small change in input can yield a completely different output, and the user may often wonder if the PCA is doing the right thing.We introduce a user interface that makes the procedure and result easier to understand. We have implemented an interactive PCA view in our text visualization tool called Text Variation Explorer. It allows the user to interactively study the result of PCA, and provides a better understanding of the process.We believe that although we are addressing the problem of interactive principal component analysis in the context of text visualization, these ideas should be useful in other contexts as well.

2017 21st International Conference Information Visualisation (IV), ISBN:978-1-5386-0831-9, ISBN:978-1-5386-0832-6

Many automatic graph drawing algorithms implement only one or two aesthetic criteria since most aesthetics conflict with each other. Empirical research has shown that although those algorithms are based on different aesthetics, drawings produced by them have comparable effectiveness.The comparable effectiveness raises a question about the necessity of choosing one algorithm against another for drawing graphs when human performance is a main concern. In this paper, we argue that effectiveness can be improved when algorithms are designed by making compromises between aesthetics, rather than trying to satisfy one or two of them to the fullest. We therefore introduce a new algorithm: BIGANGLE. This algorithm produces drawings with multiple aesthetics being improved at the same time, compared to a classical spring algorithm. A user study comparing these two algorithms indicates that BIGANGLE induces a significantly better task performance and a lower cognitive load, therefore resulting in better graph drawings in terms of human cognitive efficiency.Our study indicates that aesthetics should not be considered separately. Improving multiple aesthetics at the same time, even to small extents, will have a better chance to make resultant drawings more effective. Although this finding is based on a study of algorithms, it also applies in general graph visualization and evaluation. Highlights? We have introduced cosine force, which is to increase the size of crossing angles. ? We have introduced sine force, which is to increase the angular resolution of vertices. ? We have introduced and implemented a force-directed algorithm, which improves multiple aesthetics at the same time. ? We have conducted a human study, which was the first to examine the collective effect of multiple aesthetics on humans. ? We have presented empirical evidence showing that improving multiple aesthetics produces better graph drawings.

The use of mobile devices such as smart phones and tablets in classrooms has been met with mixed sentiments. Some instructors and teachers see them as a distraction and regularly ban their usage. Others who see their potential to enhance learning have started to explore ways to integrate them into their teaching in an attempt to improve student engagement. In this paper we report on a pilot study that forms part of a university-wide project reconceptualising its approach to the student evaluation of learning and teaching. In a progressive decision to embrace mobile technology, the university decided to trial a smart phone app designed for students to check-in to class and leave feedback on the spot. Our preliminary findings from trialling the app indicate that the application establishes a more immediate feedback loop between students and teachers. However, the app's impact depends on how feedback is shared with students and how the teaching team responds.

This paper describes the design and study of public urban screen applications aiming to facilitate urban dwellers to control content shown on public urban screens. Two types of content sharing are presented: aggregating existing social media content about particular locations for sharing, and sharing online videos with collocated people at a public urban screen. The paper describes an exploratory study, an observational study, as well as an interpretational study in regards to application usage and user experience. Sharing content on public urban screens can pique the curiosity of users towards collocated people and the application itself resulting in raised awareness of collocated people.

We have designed a mobile application that takes advantage of the built-in features of smart phones such as camera and GPS that allow users to take geo-tagged photos while on the move. Urban residents can take pictures of broken street furniture and public property requiring repair, attach a brief description, and submit the information as a maintenance request to the local government organisation of their city. This paper discusses the design approach that led to the application, highlights a built-in mechanism to elicit user feedback, and evaluates the progress to date with user feedback and log statistics. It concludes with an outlook highlighting user requested features and our own design aspirations for moving from a reporting tool to a civic engagement tool.