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OGLE-2017-BLG-1434Lb: Eighth q<1×10-4 Mass-Ratio Microlens Planet Confirms Turnover in Planet Mass-Ratio Function

Udalski A., Ryu Y.-H., Sajadian S., Gould A., Mróz P., Poleski R., Szymański M. K., Skowron J., Soszyński I., Kozłowski S., Pietrukowicz P., Ulaczyk K., Pawlak M., Rybicki K., Iwanek P., Albrow M. D., Chung S. -J., Han C., Hwang K.-H., Jung Y. K., Shin I.-G., Shvartzvald Y., Yee J. C., Zang W., Zhu W., Cha S.-M., Kim D.-J., Kim H.-W., Kim S.-L., Lee C.-U., Lee D.-J, Lee Y., Park B.-G., Pogge R. W., Bozza W., Dominik M., Helling C., Hundertmark M., Jørgensen U. G., Longa-Peña P., Lowry S., Burgdorf M., Campbell-White J., Ciceri S., Evans D., Jaimes R. F., Fujii Y. I., Haikala L. K., Henning T., Hinse T. C., Mancini L., Peixinho N., Rahvar S., Rabus M., Skottfelt J., Snodgrass C., Southworth J., von Essen C.

Acta Astronomica

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2018

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Vol. 68, No. 1

1--42

EN

We report the discovery of a cold Super-Earth planet (mp=4.4±0.5 M⊕) orbiting a low-mass (M=0.23±0.03 M⊙) M dwarf at projected separation a⊥=1.18±0.10 a.u., i.e., about 1.9 times the distance the snow line. The system is quite nearby for a microlensing planet, DL=0.86±0.09 kpc. Indeed, it was the large lens-source relative parallax πrel=1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, "microlens parallax" πE∝(πrel/M)1/2 that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio q<1×10-4. We apply a new planet-detection sensitivity method, which is a variant of "V/Vmax", to seven of these eight planets to derive the mass-ratio function in this regime. We find dN/d lnq ∝ qp, with p=1.05+0.78 -0.68, which confirms the "turnover" in the mass function found by Suzuki et al. relative to the power law of opposite sign n=-0.93±0.13 at higher mass ratios q≳2×10-4. We combine our result with that of Suzuki et al. to obtain p=0.73+0.42 -0.34.

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OGLE-2017-BLG-0373Lb: A Jovian Mass-Ratio Planet Exposes A New Accidental Microlensing Degeneracy

Skowron J., Ryu Y.-H., Hwang K.-H., Udalski A., Mróz P., Kozłowski S., Soszyński I., Pietrukowicz P., Szymański M. K., Poleski R., Ulaczyk K., Pawlak M., Rybicki K., Iwanek P., Albrow M. D., Chung S.-J., Gould A., Han C., Jung Y. K., Shin I.-G., Shvartzvald Y., Yee J. C., Zang W., Zhu W., Cha S.-M., Kim D.-J., Kim H.-W., Kim S.-L., Lee C.-U., Lee D.-J, Lee Y., Park B.-G., Pogge R. W.

Acta Astronomica

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2018

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Vol. 68, No. 1

43--61

EN

We report the discovery of microlensing planet OGLE-2017-BLG-0373Lb. We show that while the planet-host system has an unambiguous microlens topology, there are two geometries within this topology that fit the data equally well, which leads to a factor 2.5 difference in planet-host mass ratio, i.e., q=1.5×10-3 vs. q=0.6×10-3. We show that this is an "accidental degeneracy" in the sense that it is due to a gap in the data. We dub it "the caustic-chirality degeneracy". We trace the mathematical origins of this degeneracy, which should enable similar degenerate solutions to be easily located in the future. A Bayesian estimate, based on a Galactic model, yields a host mass M=0.25+0.30 -0.15 M⊙ at a distance DL=5.9+1.3 -1.95 kpc. The lens-source relative proper motion is relatively fast, μ=9 mas/yr, which implies that the host mass and distance can be determined by high-resolution imaging after about 10 years. The same observations could in principle resolve the discrete degeneracy in q, but this will be more challenging.

3

Availability analysis of series redundancy models with imperfect switchover and interrupted repairs

Shim J., Ryu H., Lee Y.

Eksploatacja i Niezawodność

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2017

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Vol. 19, no. 4

640--649

EN

This paper considers N + 1 series redundancy, where N components are active and 1 component is standby in normal state. The active components execute the service, while the standby component is ready to take over the active role if the active components fail. When an active component fails, the standby, if available, automatically takes over system operations. However, the automatic switchover of the standby component to active mode might not be possible due to hardware or software issues. When a component failure or an imperfect switchover occurs, it immediately begins to be repaired. However, the repair process is possible to be interrupted. The most existing literature of redundancy models has focused on Markovian systems with uninterrupted repairs. This paper considers a non-Markovian redundancy model with interrupted repairs, where the repair time, the non-automatic switchover time, and the interrupted time are generally distributed. Using supplementary variable method and integro-differential equations, we obtain the steady-state availability for the redundancy model.

PL

W niniejszym artykule rozważano przypadek redundancji kaskadowej typu N + 1, w której liczba N elementów pozostaje aktywnych, a jeden komponent jest w trybie gotowości w stanie normalnym. Elementy aktywne wykonują usługę, podczas gdy składowa rezerwowa pozostaje w stanie gotowości do przejęcia roli aktywnej w przypadku, gdyby składniki aktywne uległy uszkodzeniu. Gdy element aktywny przestaje działać, element zastępczy, jeśli jest dostępny, automatycznie przejmuje operacje systemowe. Jednak automatyczne przełączenie komponentu zastępczego na tryb aktywny nie zawsze jest możliwe z powodu problemów ze sprzętem lub oprogramowaniem. Jeśli wystąpi awaria komponentu lub niedoskonałe przełączenie, natychmiast rozpoczyna się naprawa. Proces naprawy może jednak zostać przerwany. Większośćistniejącej literatury na temat modeli nadmiarowości koncentruje się na systemach Markowa, w których nie dochodzi do przerwania naprawy. W niniejszym artykule rozważano niemarkowowski model nadmiarowości uwzględniający możliwość przerwania naprawy, w którym czas naprawy, czas nieautomatycznego przełączenia oraz czas przerwany mają rozkład ogólny. Wykorzystując metodę dodatkowej zmiennej oraz równania całkowo-różniczkowe otrzymano gotowość stacjonarną dla omawianego modelu redundancji.

4

Non-parametric machine learning methods for evaluating the effects of traffic accident duration on freeways

Lee Y., Wei C.-H., Chao K.-C.

Archives of Transport

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2017

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Vol. 43, iss. 3

91--104

EN

Traffic accidents usually cause congestion and increase travel-times. The cost of extra travel time and fuel consumption due to congestion is huge. Traffic operators and drivers expect an accurately forecasted accident duration to reduce uncertainty and to enable the implementation of appropriate strategies. This study demonstrates two non-parametric machine learning methods, namely the k-nearest neighbour method and artificial neural network method, to construct accident duration prediction models. The factors influencing the occurrence of accidents are numerous and complex. To capture this phenomenon and improve the performance of accident duration prediction, the models incorporated various data including accident characteristics, traffic data, illumination, weather conditions, and road geometry characteristics. All raw data are collected from two public agencies and were integrated and cross-checked. Before model development, a correlation analysis was performed to reduce the scale of interrelated features or variables. Based on the performance comparison results, an artificial neural network model can provide good and reasonable prediction for accident duration with mean absolute percentage error values less than 30%, which are better than the prediction results of a k-nearest neighbour model. Based on comparison results for circumstances, the Model which incorporated significant variables and employed the ANN method can provide a more accurate prediction of accident duration when the circumstances involved the day time or drunk driving than those that involved night time and did not involve drunk driving. Empirical evaluation results reveal that significant variables possess a major influence on accident duration prediction.

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Phase Transformation And Mechanical Properties Of Ti-12.1Mo-1Fe Alloy With Nano-Sized Precipitation

Lee D.-G., Seo J., Li Ch., Lee Y.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1393--1396

EN

Microstructural characterization and aging hardening behaviors of a new designed Ti-12.1Mo-1Fe alloy during solution treatment and aging were investigated in the present study. It is well known that when β-Ti alloys are generally under solution treatment or aging, α phases and ω phases appear or disappear dependent on heat treatment temperature and holding time. It is very necessary to understand the phase transformation phenomenon and to control the microstructure because these phases can control the drastic changes of the mechanical and physical properties of these alloys. According to the calculated [Mo]eq value and the microstructural observation, the β-transus temperature was about 780°. After the solution treatment, this alloy was composed of the β-phase and the microstructure mainly consisted of the equiaxed β grains with the average size of 25 μm. ω phases which were precipitated during aging process, played a more important role to the hardening effect than α phases. The highest hardness value of Ti-12.1Mo-1Fe alloy showed in the condition of the aging temperature of 450°. The hardening due to ω-phase precipitation can lead to a high hardness about 480 Hv but the coarse α-phase result in hardness below 300 Hv.

6

Kinematic and kinetic analyses of novice running in dress shoes and running shoes

Lee Y., Kim Y. K., Kim Y. H., Kong S., Lee K. K.

Acta of Bioengineering and Biomechanics

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2011

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Vol. 13, no. 3

55-61

EN

The purpose of the study was to investigate how novice runners adjust their lower extremities in heel-toe running while they wear dress shoes and running shoes. Ten novice male runners repeatedly ran across a force plate at 4 m/s in each type of shoes. Joint kinematics and kinetics, vertical ground reaction force, and utilized coefficient of friction during the stance phase were quantified. The results obtained showed no differences in impact peaks, stance time, stride length and joint kinematics. However, dorsiflexion moment was significantly greater with dress shoes (407 Nm) compared to that with running shoes (304 Nm; p < 0.05). Compared to the runners in running shoes (0.23), the runners in dress shoes (0.20) achieved a significantly lower utilized coefficient of friction ( p < 0.05). When running in dress shoes, novice runners tended to use better a dorsiflexion moment than when running in running shoes. This adaptation appears to minimize the chances of slipping at the moment of heel strike.

7

Weathering effects on themanufacturing process of GRC material

Ho C. Y., Lee Y.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

241-246

EN

Purpose: Weathering effects on the weight and shrinkage strain of GFRC composite material are experimentally investigated in this paper. The five samples with different percents of glass fibers are chosen to test the effectsof humidity on the deformation of GRC. Design/methodology/approach: These samples are exposed to the environment with different humidity. Findings: GRC was considered for the fabrication of 30m high telecommunication towers. Other structural suchas pedestrian bridges, roof elements and floor slabs were also studied. Practical implications: The experimental results show that the effect of weight change on strain at dryenvironment is more significant than wet environment, and GFRC with 5% of glass fiber obviously reduces theweight change and strain. Originality/value: In this paper the variation of absorbing water rate, edabsorbing water rate, shrinkage strain, weight change, temperature, expansion strain and temperature change rate of GRC material with time wasexperimentally investigated.

8

Development of micro ceramic gas turbine based on mini jet engine

Yoshida H., Sodeoka S., Iki N., Matsunuma T., Inoue T., Suzuki M., Ebara T., Lee Y.

Prace Naukowe Politechniki Warszawskiej. Konferencje

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2005

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z. 24

365--374

EN

Ceramic Gas Turbine can achieve high thermal efficiency without cooling system of turbine blades. However, ceramic elements are too expensive for development and introduction stage. Thus a hybrid type gas turbine of ceramic parts and metal parts are designed and manufactured. The hottest parts i.e., a turbine nozzle and rotor are replaced to ceramic type. But its combustor is still made of metal. The baseline machine is a small single-shaft turbojet engine (J-850, Sophia Precision, Co., Ltd.) with a centrifugal compressor and a radial turbine. An Inconel 713C alloy turbine rotor was replaced into a ceramic rotor (SN-235, Kyocera Corporation). The Inconel turbine nozzle and casing were replaced into the ceramic parts (SN-01, Otsuka Ceramics Co., Ltd.). The ceramic nozzle and case is supported by metal parts. As a first step, only turbine rotor was replaced with a ceramic rotor. A test operation was conducted at rotating speeds of up to 140,000 rpm in atmospheric air. As a second step, the Inconel turbine nozzle and turbine nozzle casing were replaced with ceramic parts. The ceramic nozzle and case were supported by metal parts. Through tests with the ceramic nozzle, it became evident that one of the key technologies for the development of ceramic gas turbines is the design of the interface between the ceramic components and the metallic components, because the difference between the coefficients of linear thermal expansion of the ceramic and metal produces large thermal stress at their interface in the high-temperature condition. Therefore a buffer material made of alumina fiber was inserted at the interface between the ceramic and metal. However alumina fiber is not tough enough for repeat of assembly and disassembly. The metallic spring ring seal can be applied instead of the alumina fiber, because the wall temperature of the combustor is not as high as the turbine inlet temperature due to the cooling effect of the combustion air. This metallic seal and the ceramic rotor were assembled into the gas turbine. This engine could operate for 1 hour in the condition that the estimated turbine inlet temperature was over 1000 °C.

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Sound absorption properties of recycled polyester fibrous assembly absorbers

Lee Y., Joo C.

Autex Research Journal

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2003

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Vol. 3, no. 2

78--84

EN

Sound absorption materials are generally classified into three types, porous, resonator, and panel. All of these three types are based on the theory of energy transforming from sound energy to thermal energy. In this paper, we examined the sound absorption coefficient of recycled polyester nonwovens for the purpose of substituting the conventionally used materials such as glasswool and rockwool. The use of recycled polyester nonwovens has many advantages compared to conventional sound absorbers, including reduced product cost, good handling, and environmental protection. The sound absorption coefficient of the recycled polyester nonwovens was determined by a two-microphone impedance measurement tube; the determination of the noise absorption coefficient is nothing more than the absorption energy rate of the material against the incidence energy. We have determined the relationship between the acoustic absorption values measured and the nonwoven parameters including fibre properties and web properties.

10

Facial expression recognition based on dimension model using automated feature extraction

Shin Y., Lee S., Lee Y.

Machine Graphics and Vision

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2000

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Vol. 9, No. 3

573-585

EN

This paper presents a facial expression recognition based on dimension model of internal states that uses automated feature extraction. We apply this approach mostly for the frontal pose. Features of facial expressions are extracted automatically in three steps. In the first steo, Gabor wavelet representation can provide edges extraction of major face components using the average value of the image's 2D Gabor wavelet coefficient fistogram. In the second step, sparse features of facial expressions are extracted using fuzzy C-means clustering (FCM) algorithm for neural faces, and in the third step, using the dynamic model (DM) for expression images. The result of facial expression recognition is compared with dimensional values of internal states derived from semantic ratings of words related to emotion by experimental subjects. The dimensional model can recognize not only 6 facial expressions related to Ekman's basic emotions, but also expressions of various internal states. A facial expression in the dimension model includes two dimensions which are pleasure-upleasure and arousal-sleep. We show the result of expression recognition in the dimension model. In this paper, with the dimension model we have improved the limitations of expression recognition based on basic emotions, and have extracted features automatically with a new approach using the FCM algorith and the Dynamic Model.