• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.3
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• pp.421-432
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• 2013

This paper describes implementation of functions for mobile robot localization, which is one of the vital technologies for autonomous navigation of a mobile robot. There are several function libraries for mobile robot navigation. Some of them have limited applicability for practical use since they can be used only for simulation. Our research focuses on development of functions which can be used for localization of indoor robots. The functions implement deadreckoning and motion model of mobile robots, measurement model of range sensors, and frequently used calculations on angular directions. The functions encompass various types of robots and sensors. Also, various types of uncertainties in robot motion and sensor measurements are implemented so that the user can select proper ones for their use. The functions are tested and verified through simulation and experiments.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.111-119
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• 2015

BACKGROUND: Ethychlozate (ECZ) is a plant growth regulator of synthetic auxin for agricultural commodities (ACs). Accurate and sensitive method to determine ECZ in diverse ACs on global official purpose is required to legal residue regulation. As the current official method is confined to the limited type of crops with poor validation, this study was conducted to improve and extend the ECZ method using high-performance liquid chromatography (HPLC) in all the registered crops with method verification. METHODS AND RESULTS: ECZ and its acidic metabolite (ECZA) were both extracted from acidified samples with acetone and briefly purified by dichloromethane partition. ECZ was hydrolyzed to form ECZA and the combined ECZA was finally purified by ion-associated partition including hexane-washing. The instrumental quantitation was performed using HPLC/ FLD under ion-suppression of ECZA with no interference by sample co-extractives. The average recoveries of intra- and inter-day experiment ranged from 82.0 to 105.2% and 81.7 to 102.8%, respectively. The repeatability and reproducibility for intra- and inter-day measurements expressed as a relative standard deviation was less than 8.7% and 7.4%, respectively. CONCLUSION: Established analytical method for ECZ residue in ACs was applicable to the nation-wide pesticide residues monitoring program with the acceptable level of sensitivity, repeatability and reproducibility.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.540-544
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• 2015

A bath for electrodeposition of platinum nanoparitcles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the elecrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.

• Applied Microscopy
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• v.47 no.3
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• pp.110-120
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• 2017

Non-isothermal thermogravimetry (TG) measurements on melt-quenched $Bi_xSe_{100-x}$ specimens (x=0, 2.5, 7.5 at%) were made at a heating rate ${\beta}=10^{\circ}C/min$ in the range $T=35^{\circ}C{\sim}950^{\circ}C$. The as-measured TG curves confirm that $Bi_xSe_{100-x}$ samples were thermally stable with minor loss at $T{\leq}400^{\circ}C$ and mass loss starts to decrease up to $600^{\circ}C$, beyond which trivial mass loss was observed. These TG curves were used to estimate molar (Se/Bi)-ratios of $Bi_xSe_{100-x}$ samples, which were not in accordance with initial composition. Shaping features of conversion curves ${\alpha}(T)-T$ of $Bi_xSe_{100-x}$ samples combined with a reliable flow chart were used to reduce kinetic mechanisms that would have caused their thermal mass loss to few nth-order reaction models of the form $f[{\alpha}(T)]{\propto}[1-{\alpha}(T)]^n$ (n=1/2, 2/3, and 1). The constructed ${\alpha}(T)-T$ and $(d{\alpha}(T)/dT)-T$ curves were analyzed using Coats-Redfern (CR) and Achar-Brindley-Sharp (ABS) kinetic formulas on basis of these model functions, but the linearity of attained plots were good in a limited ${\alpha}(T)-region$. The applicability of CR and ABS methods, with model function of kinetic reaction mechanism R0 (n=0), was notable as they gave best linear fits over much broader ${\alpha}(T)-range$.

• Smart Structures and Systems
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• v.15 no.2
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• pp.489-503
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• 2015

Response estimation at unmeasured locations using the limited number of measurements is an attractive topic in the field of structural health monitoring (SHM). Because of increasing complexity and size of civil engineering structures, measuring all structural responses from the entire body is intractable for the SHM purpose; the response estimation can be an effective and practical alternative. This paper investigates a response estimation technique based on the Kalman state estimator to combine multi-sensor data under non-zero mean input excitations. The Kalman state estimator, constructed based on the finite element (FE) model of a structure, can efficiently fuse different types of data of acceleration, strain, and tilt responses, minimizing the intrinsic measurement noise. This study focuses on the effects of (a) FE model error and (b) combinations of multi-sensor data on the estimation accuracy in the case of non-zero mean input excitations. The FE model error is purposefully introduced for more realistic performance evaluation of the response estimation using the Kalman state estimator. In addition, four types of measurement combinations are explored in the response estimation: strain only, acceleration only, acceleration and strain, and acceleration and tilt. The performance of the response estimation approach is verified by numerical and experimental tests on a simply-supported beam, showing that it can successfully estimate strain responses at unmeasured locations with the highest performance in the combination of acceleration and tilt.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.349-355
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• 2015

Underwater robots generally show better performances for tasks than humans under certain underwater constraints such as. high pressure, limited light, etc. To properly diagnose in an underwater environment using remotely operated underwater vehicles, it is important to keep autonomously its own position and orientation in order to avoid additional control efforts. In this paper, we propose an efficient method to assist in the operation for the various disturbances of a remotely operated vehicle for the diagnosis of underwater structures. The conventional AHRS-based bearing estimation system did not work well due to incorrect measurements caused by the hard-iron effect when the robot is approaching a ferromagnetic structure. To overcome this drawback, we propose a sensor fusion algorithm with the camera and AHRS for estimating the pose of the ROV. However, the image information in the underwater environment is often unreliable and blurred by turbidity or suspended solids. Thus, we suggest an efficient method for fusing the vision sensor and the AHRS with a criterion which is the amount of blur in the image. To evaluate the amount of blur, we adopt two methods: one is the quantification of high frequency components using the power spectrum density analysis of 2D discrete Fourier transformed image, and the other is identifying the blur parameter based on cepstrum analysis. We evaluate the performance of the robustness of the visual odometry and blur estimation methods according to the change of light and distance. We verify that the blur estimation method based on cepstrum analysis shows a better performance through the experiments.

• Clinics in Shoulder and Elbow
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• v.18 no.4
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• pp.211-216
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• 2015

Background: Few studies have investigated magnetic resonance (MR) characteristics of traumatic posterosuperior rotator cuff tears involving the supraspinatus and infraspinatus. We hypothesized that traumatic rotator cuff tears may have MR characteristics distinguishable from those of non-traumatic tears. Methods: Preoperative MR arthrography and intraoperative tear size measurements were compared in 302 patients who underwent MR arthrography and subsequent arthroscopic rotator cuff repairs for traumatic (group T, 61 patients) or non-traumatic (group NT, 241 patients) tears. The inclusion criteria for both groups were posterosuperior full-thickness rotator cuff tear and age between 40 and 60 years. For group T, traumas were limited to accidental falls or slips, or sports injuries, motor vehicle accidents; injuries were associated with acute onset of pain followed by functional shoulder impairment; and time between injury and magnetic resonance imaging (MRI) was 6 weeks or less. Results: In group T, 72.1% of shoulders (44 patients) had tendon tears with blunt edges while 27.9% of shoulders (17 patients) had tears with tapering edges. In contrast, 21.2% of patients in group NT (51 patients) had blunt-edge tears, while 78.8% (190 patients) of tears had tapering edges. These results were statistically significant (p<0.001) and estimated odds ratio was 9.6. The size of tear did not vary significantly between groups. Conclusions: We found no exclusive MR characteristic to define traumatic tears. However, oblique coronal MRI of traumatic tears showed a significant tendency for abrupt and rough torn tendon edges and relatively consistent tendon thicknesses (without lateral tapering) compared to non-traumatic cuff tears.

• The Korean Journal of Quaternary Research
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• v.14 no.1
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• pp.57-63
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• 2000

A simulation model was used to examine the effects of climate variation on the tree-ring structure of Larix leptolepis trees growing at a plantation plot in Worak National Park in central Korea. The model uses mathematical equations to simulate processes affecting cell(tracheid) size variations for individual rings using daily precipitation and temperature measurements. Limiting conditions are estimated from temperature, day length and a calculated water balance. The results indicate that the seasonal growth is mostly limited by the soil moisture content and precipitation income during April and May. The April-May temperature also inversely influences the growth by increasing water losses from soil. The global climate-change scenario which includes regional warming(increasing temperature in spring-summer periods) appears to decrease the duration of optimal growths. Consequently, the model estimated that Larix leptolepis would lose the total production of xylem by 25%.

• Journal of Acupuncture Research
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• v.26 no.4
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• pp.11-18
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• 2009

Objectives : The objective of this review was to evaluate clinical trials of warming acupuncture for musculoskeletal pain diseases, to assess the methodologic quality of the trials and determine whether low-quality trials are associated with positive outcomes, to document adverse effects and to identify the effectiveness of the warming acupuncture. Methods : Seven databases and the Journal ZHONGGUO ZHENJIU(中國鍼灸) published between 2004－2008 were searched. Korean and Chinese randomized trials were evaluated for methodologic quality using the modified Jadad scale. Outcome measurements were pain, function and global improvement. The best-evidence synthesis was performed to determine the strength of evidence by control group. Results : Six clinical trials representing 564 patients with musculoskeletal pain diseases were identified. For pain and function, there was moderate evidence that warming acupuncture is more effective than manual acupuncture. For patient global assesment, there was limited evidence that warming acupuncture is more effective than manual acupuncture. However, for function, there was inconclusive evidence that warming acupuncture is more effective than acupuncture with TDP or western medicine or acupoint-injection treatment. Conclusions : The evidence suggests that warming acupuncture is more effective for musculoskeletal pain diseases than manual acupuncture, acupuncture with TDP, western medicine and acupoint-injection treatment. But the evidence is moderate to inclusive due to the low methodologic quality of the trials. Further clinical trials with high methodologic quality is required to investigate the effectiveness of warming acupuncture.

• The korean journal of orthodontics
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• v.43 no.3
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• pp.134-140
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• 2013

Objective: To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods: CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal-Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results: Labial alveolar bone thickness was significantly higher in Class I group compared to Class II group (p = 0.003). Lingual alveolar bone angle (p = 0.004), lower incisor protrusion (p = 0.007) and proclination (p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner (p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup (p = 0.004). Conclusions: Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients.