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Diel vertical migration of the copepod Calanus sinicus before and during formation of the Yellow Sea Cold Bottom Water in the Yellow Sea

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Acta Oceanologica Sinica 2013年第9期32卷 99-106页

作者： KANG Jung-Hoon seo MinHo KWON Oh Youn KIM Woong-seo South Sea Environment Research Division Korea Institute of Ocean Science&Technology (KIOST) Deep-sea and Seabed Resources Research Division

To understand the effects of the Yellow Sea Cold Bottom Water （YSCBW） on the diel vertical migration （D- VM） of the copepod Calanus sinicus, we surveyed vertical distribution of C. sinicus at a fixed station in the Yellow Sea before （spring） and during （summer） formation of the YSCBW. Cold water （〈10℃） was observed in the bottom layer when the water column was thermally stratified in summer, but the water column was thermally well-mixed in spring 2010. Samples were collected from five different layers at 3-h intervals using an opening-closing net. Adult females （1-155 ind./m3） showed a clear normal DVM pattern throughout the entire water column in spring, whereas adult males did not migrate. DVM of copepodite V （CV） individuals was not clear, but the maximum abundance of CI-CIV occurred consistently in the upper 10-20 m layer, where there was a high concentration of chlorophyll-a （Chl-a）（0.49-1.19μg/L）. In summer, weak DVM was limited to cold waters beneath the thermocline for adult females （〈30 ind./m3）, but not for adult males. The maximum abundance of CI-CIV also occurred consistently in the subsurface layer （20-40 m） together with high concentrations of Chl-a （0.81-2.36 μg/L）. CV individuals （1-272 ind./m3） moved slightly upward noc- turnally to the near-surface layer （10-20 m）, where the average temperature was 25.74℃, but they were not found in the surface layer （0-10 m; 28.31℃）. These results indicate that the existence of the YSBCW affected food availability at depth and the vertical temperature distribution, leading to variation in the amplitude and shape of stage-specific vertical distributions （CI to adults） in C. sinicus before and during the formation of cold waters in the Yellow Sea during the study period.

关键词： Yellow Sea Cold Bottom Water (YSCBW) copepod Calanus sinicus developmental stages,diel vertical migration (DVM)

Magnetic-fluid microelectromechanical light modulator

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光学精密工程 2005年第5期13卷 542-547页

作者： seo Jong-wook WANG Xi-jun School of Electronic and Electrical Engineering Hongik University 72-1 Sangsu-dong Mapo-gu Seoul 121-791 Rep. Korea Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences Changchun 130033 China

A new microfluidic microelectromechanical light modulator using a magnetic fluid is introduced. The optical reflection from the device is modulated by applying an electric current into an electrode, which is enclosed by ferromagnetic thin films as in an inductive head for a magnetic data storage device. The magnetic field produced by the current exerts a magnetic force on the magnetic fluid and drives the fluid to cover the cell surface. The surface tension of the fluid provides a restoring force when the field is reduced. The actuation of the fluid is completed in about 12 ms for both thin-to-thick and thick-to-thin fluid film switchings by magnetic forces and surface tension forces, respectively. It was observed that the switching speed was almost independent of the driving current, and no considerable thermal effect were observed when driven by a current up to 100 mA.

关键词：微电子学光调节器磁性流动性 FPD MEMS 弯曲效应电极有限元法 FEM

Evaluation of Remote-I/O Support for a DSM-Based Computation Offloading Scheme

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Journal of Computer Science & Technology 2017年第5期32卷 957-973页

作者： Yuhun Jun Jaemin Lee Euiseong seo College of Software Sungkyunkwan University Suwon 16419 Korea

Computation offloading enables mobile devices to execute rich applications by using the abundant computing resources of powerful server systems. The distributed shared memory based (DSM-based) computation offloading approach is expected to be especially popular in the near future because it can dynamically migrate running threads to computing nodes and does not require any modifications of existing applications to do so. The current DSM-based computation offloading scheme, however, has focused on efficiently offloading computationally intensive applications and has not considered the significant performance degradation caused by processing the I/O requests issued by offloaded threads. Because most mobile applications are interactive and thus yield frequent I/O requests, efficient handling of I/O operations is critically important. In this paper, we quantitatively analyze the performance degradation caused by I/O processing in DSM-based computation offloading schemes using representative commodity applications. To remedy the performance degradation, we apply a remote I/O scheme based on remote device support to computation offloading. The proposed approach improves the execution time by up to 43.6% and saves up to 17.7% of energy consumption in comparison with the existing offloading schemes. Selective compression of the remote I/O scheme reduces the network traffic by up to 53.5%.

关键词： computation offloading mobile-cloud computing distributed shared memory (DSM) mobile computing

Experimental Study on Drag-induced Balancing via a Static Tail for Water-running Robots

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Journal of Bionic Engineering 2016年第4期13卷 537-543页

作者： DongGyu Lee HyunGyu Kim TaeWon seo School of Mechanical Engineering Yeungnam University Gyeongsan 712-749 Republic of Korea

Robotics is one area of research in which bio-inspiration is an effective way to design a system by investigating the working principles of nature. Recently, tails have received interest in robotics to increase stability and maneuverability. In this study, we investigated the effectiveness of a static tail for bio-inspired water-running locomotion. The tail was added to increase the stability in the rolling and yawing directions based on the hydrodynamic force from interaction between the tail and the water. The drag coefficient in the interaction is not easy to calculate analytically, so experimental studies were done for various static tail shapes. Five different shapes and compliances in two directions were considered for experimental design candidates. The result was applied to design a stable amphibious robot that can run on ground and water surfaces.

关键词： bio-inspiration water-running robot static tail stability hydrodynamic balancing basilisk lizard

Analysis and Experiment on the Steering Control of a Water-running Robot Using Hydrodynamic Forces

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Journal of Bionic Engineering 2017年第1期14卷 34-46页

作者： HyunGyu Kim Kyungmin Jeong TaeWon seo School of Mechanical Engineering Yeungnam University Gyeongsan 712-749 Republic of Korea Nuclear Convergence Technology Division Korea Atomic Energy. Research Institute Daejeon 305-353 Republic of Korea

Steering is important for the high maneuverability of mobile robots. Many studies have been performed to improve the maneuverability using a tail. The aim of this research was to verify the performance of a water-running robot steering on water using a tail. Kinematic analysis was performed for the leg mechanism and the interaction forces between the water and the feet to calculate the propulsive drag force of the water. This paper suggests a simplified planar two-link rigid body model to determine the dynamic performance of the robotic platform with respect to the effect of the tail＇s motion. Simulations based on a dynamic model were performed by applying a range of motions to the tail. In addition, a simulation with a Bang-bang controller was also performed to control the main frame＇s yawing locomotion. Finally, an experiment was conducted with the controller, and the simulation and experimental results were compared. These results can be used as a guideline to develop a steerable water-running robot.

关键词： basilisk lizard water-running robot steering Static Tail (ST) Dynamic Tail (DT) planar two-link rigid body

A Synthesis of Multi-Precision Multiplication and Squaring Techniques for 8-Bit Sensor Nodes＂ State-of-the-Art Research and Future Challenges

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Journal of Computer Science & Technology 2016年第2期31卷 284-299页

作者： Zhe Liu Hwajeong seo Howon Kim Laboratory of Algorithmics Cryptology and Security University of Luxembourg Kirchberg L-1359 Luxembourg School of Computer Science and Engineering Pusan National University Busan 609-735 Korea

Multi-precision multiplication and squaring are the performance-critical operations for the implementation of public-key cryptography, such as exponentiation in RSA, and scalar multiplication in elliptic curve cryptography （ECC）. In this paper, we provide a survey on the multi-precision multiplication and squaring techniques, and make special focus on the comparison of their performance and memory footprint on sensor nodes using 8-bit processors, Different from the previous work, our advantages are in at least three aspects. Firstly, this survey includes the existing techniques for multi- precision multiplication and squaring on sensor nodes over prime fields. Secondly, we analyze and evaluate each method in a systematic and objective way. Thirdly, this survey also provides suggestions for selecting appropriate multiplication and squaring techniques for concrete implementation of public-key cryptography. At the end of this survey, we propose the research challenges on efficient implementation of the multiplication and the squaring operations based on our observation.

关键词： public-key cryptography multi-precision multiplication multi-precision squaring 8-bit AVR microprocessor

Propulsion Modeling and Analysis of a Biomimetic Swimmer

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Journal of Bionic Engineering 2010年第3期7卷 259-266页

作者： Ngoc San Ha Nam seo Goo Smart Microsystem Research Lab. Department of Advanced Technology FusionKonkuk University

We have studied a biomimetic swimmer based on the motion of bacteria such as Escherichia coli (E. coli) theoretically andexperimentally. The swimmer has an ellipsoidal cell body propelled by a helical filament. The performance of this swimmer wasestimated by modeling the dynamics of a swimmer in viscous fluid. We applied the Resistive Force Theory (RFT) on this modelto calculate the linear swimming speed and the efficiency of the model. A parametric study on linear velocity and efficiency tooptimize the design of this swimmer was demonstrated. In order to validate the theoretical results, a biomimetic swimmer wasfabricated and an experiment setup was prepared to measure the swimming speed and thrust force in silicone oil. The experimentalresults agree well with the theoretical values predicted by RFT. In addition, we studied the flow patterns surrounding thefilament with a finite element simulation with different Reynolds number (Re) to understand the mechanism of propulsion. Thesimulation results provide information on the nature of flow patterns generated by swimming filament. Furthermore, the thrustforces from the simulation were compared with the thrust forces from theory. The simulation results are in good agreement withthe theoretical results.

关键词： biomimetic microrobots swimming microrobots propulsion of flagella flow visualization medical application

Android IoT Lifelog System and Its Application to Motion Inference

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Computer Systems Science & Engineering 2023年第6期45卷 2989-3003页

作者： Munkhtsetseg Jeongwook seo Next Social Platform LLC. Ulaanbaatar15150Mongolia Department of IT Transmedia Contents Hanshin UniversityOsan-si18101Korea

In social science,health care,digital therapeutics,etc.,smartphone data have played important roles to infer users’daily ***,smartphone data col-lection systems could not be used effectively and widely because they did not exploit any Internet of Things(IoT)standards(e.g.,oneM2M)and class labeling methods for machine learning(ML)***,in this paper,we propose a novel Android IoT lifelog system complying with oneM2M standards to collect various lifelog data in smartphones and provide two manual and automated class labeling methods for inference of users’daily *** proposed system consists of an Android IoT client application,an oneM2M-compliant IoT server,and an ML server whose high-level functional architecture was carefully designed to be open,accessible,and internation-ally recognized in accordance with the oneM2M *** particular,we explain implementation details of activity diagrams for the Android IoT client application,the primary component of the proposed *** results verified that this application could work with the oneM2M-compliant IoT server normally and provide corresponding class labels *** an application of the proposed system,we also propose motion inference based on three multi-class ML classifiers(i.e.,k nearest neighbors,Naive Bayes,and support vector machine)which were created by using only motion and location data(i.e.,acceleration force,gyroscope rate of rotation,and speed)and motion class labels(i.e.,driving,cycling,running,walking,and stil-ling).When compared with confusion matrices of the ML classifiers,the k nearest neighbors classifier outperformed the other two ***,we evaluated its output quality by analyzing the receiver operating characteristic(ROC)curves with area under the curve(AUC)*** AUC values of the ROC curves for all motion classes were more than 0.9,and the macro-average and micro-average ROC curves achieved very high AUC values of 0.96 and 0.99,res

关键词： Android Internet of Things lifelog motion inference oneM2M

Joint On-Demand Pruning and Online Distillation in Automatic Speech Recognition Language Model Optimization

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Computers, Materials & Continua 2023年第12期77卷 2833-2856页

作者： Soonshin seo Ji-Hwan Kim Clova Speech Naver CorporationSeongnam13561Korea Department of Computer Science and Engineering Sogang UniversitySeoul04107Korea

Automatic speech recognition(ASR)systems have emerged as indispensable tools across a wide spectrum of applications,ranging from transcription services to voice-activated *** enhance the performance of these systems,it is important to deploy efficient models capable of adapting to diverse deployment *** recent years,on-demand pruning methods have obtained significant attention within the ASR domain due to their adaptability in various deployment ***,these methods often confront substantial trade-offs,particularly in terms of unstable accuracy when reducing the model *** address challenges,this study introduces two crucial empirical ***,it proposes the incorporation of an online distillation mechanism during on-demand pruning training,which holds the promise of maintaining more consistent accuracy ***,it proposes the utilization of the Mogrifier long short-term memory(LSTM)language model(LM),an advanced iteration of the conventional LSTM LM,as an effective alternative for pruning targets within the ASR *** rigorous experimentation on the ASR system,employing the Mogrifier LSTM LM and training it using the suggested joint on-demand pruning and online distillation method,this study provides compelling *** results exhibit that the proposed methods significantly outperform a benchmark model trained solely with on-demand pruning ***,the proposed strategic configuration successfully reduces the parameter count by approximately 39%,all the while minimizing trade-offs.

关键词： Automatic speech recognition neural language model Mogrifier long short-term memory pruning distillation efficient deployment optimization joint training