Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

This study was conducted to monitor the residual pesticides on red pepper powder produced in five regions, which are the major producers of red pepper in Korea, such as Ham-pyeong, An-dong, Yeong-yang, Yeong-gwang, and Cheongyang from 2015 to 2016. Residual pesticides were detected on all samples. Among the 286 pesticides tested, 58 pesticides were detected, with the most frequently detected being chlorfenapyr (93.7%). Twelve types of pesticides (chlorfenapyr, cypermethrin, chlorpyrifos, pyraclostrobin, cyhalothrin, tebuconazole, bifenthrin, deltamethrin, fenvalerate, lufenuron, azoxystrobin, and indoxacarb) were detected in all regions, and 14 types of pesticides were used only in certain regions. An analysis of the residual pesticides showed that none of the pesticides detected exceeded the MRL (Maximum Residue Limits). The Positive List System (PLS) requirements were applied to eight pesticides that had no set MRLs. 0.01 mg/kg (PLS requirements) was exceeded in 12 cases. A comparison of the estimated daily intake (EDI) of pesticides with the acceptable daily intake (ADI) to access their risk revealed %ADI values of 0.001-0.756. Carbofuran showed the highest (0.756%), but most pesticides were below 1%. The results show that residual pesticides in red pepper powder are at safe levels.

In this study, the nutritional components (moisture, fat, protein, ash) value of military hardtack was collected and analyzed to control the mixing ratio of rice and flour. Hardtack from 4 factories was analyzed by 3 testing organizations certified by the Korean Ministry Food and Drug Safety. In addition, the accuracy and collaborative study possibility of each organization were evaluated in Q-test and HorRat. Also, other hardtack groups with different mixing ratios were compared to quality control of hardtack by I-MR charts. As a result, the HorRat and Q-test values of test organizations were 0.5-6.2 and 0.08-0.91, respectively. The quality of hardtack by the factories was similar. However, for accurate management of the mixing ratio, suggesting both upper and lower limit requirements of the nutritional components is necessary.

Near Infra-red (NIR) analytical method was applied to quantify fat, moisture, protein, and salt in meat products. To ensure an accurate analysis, the NIR analysis method was compared with Korean food standard codex method. Correlation coefficients were 0.961-0.997, and the ratio of standard error of prediction (SEP) with standard error of laboratory (SEL) were 1.01-1.32. Z-score and Q score were −0.02-0.95 and −0.27-0.15, respectively. A control chart was conducted for three meat products. Each control chart data consisted of fat, moisture, protein, and salt, and it was produced by NIR analysis. The control chart of meat products was used for quality control.

This technical paper deals the practical transformation algorithms between several lunar reference frames which will be used for Korea pathfinder lunar orbiter (KPLO) flight operation. Despite of various lunar reference frame definitions already exist, use of a common transformation algorithm while establishing lunar reference frame is very important for all members related to KPLO mission. This is because use of slight different parameters during frame transformation may result significant misleading while reprocessing data based on KPLO flight dynamics. Therefore, details of practical transformation algorithms for the KPLO mission specific lunar reference frames is presented with step by step implementation procedures. Examples of transformation results are also presented to support KPLO flight dynamics data user community which is expected to give practical guidelines while post processing the data as their needs. With this technical paper, common understandings of reference frames that will be used throughout not only the KPLO flight operation but also science data reprocessing can be established. It is expected to eliminate, or at least minimize, unnecessary confusion among all of the KPLO mission members including: Korea Aerospace Research Institute (KARI), National Aeronautics and Space Administration (NASA) as well as other organizations participating in KPLO payload development and operation, or further lunar science community world-wide who are interested in KPLO science data post processing.

In this work, preliminary launch opportunities from NARO Space Center to the Sun-Earth Lagrange point are analyzed. Among five different Sun-Earth Lagrange points, L1 and L2 points are selected as suitable candidates for, respectively, solar and astrophysics missions. With high fidelity dynamics models, the L1 and L2 point targeting problem is formulated regarding the location of NARO Space Center and relevant Target Interface Point (TIP) for each different launch date is derived including launch injection energy per unit mass (C3), Right ascension of the injection orbit Apoapsis Vector (RAV) and Declination of the injection orbit Apoapsis Vector (DAV). Potential launch periods to achieve L1 and L2 transfer trajectory are also investigated regarding coasting characteristics from NARO Space Center. The magnitude of the Lagrange Orbit Insertion (LOI) burn, as well as the Orbit Maintenance (OM) maneuver to maintain more than one year of mission orbit around the Lagrange points, is also derived as an example. Even the current work has been made under many assumptions as there are no specific mission goals currently defined yet, so results from the current work could be a good starting point to extend diversities of future Korean deep-space missions.

The ground tracking support is a critical factor for the navigation performance of spacecraft orbiting around the Moon. Because of the tracking limit of antennas, only a small number of facilities can support lunar missions. Therefore, case studies for various ground tracking support conditions are needed for lunar missions on the stage of preliminary mission analysis. This study analyzes the ground supporting condition effect on orbit determination (OD) of Korea Pathfinder Lunar Orbiter (KPLO) in the lunar orbit. For the assumption of ground support conditions, daily tracking frequency, cut-off angle for low elevation, tracking measurement accuracy, and tracking failure situations were considered. Two antennas of deep space network (DSN) and Korea Deep Space Antenna (KDSA) are utilized for various tracking conditions configuration. For the investigation of the daily tracking frequency effect, three cases (full support, DSN 4 pass/day and KDSA 4 pass/day, and DSN 2 pass/day and KDSA 2 pass/day) are prepared. For the elevation cut-off angle effect, two situations, which are 5 deg and 10 deg, are assumed. Three cases (0%, 30%, and 50% of degradation) were considered for the tracking measurement accuracy effect. Three cases such as no missing, 1-day KDSA missing, and 2-day KDSA missing are assumed for tracking failure effect. For OD, a sequential estimation algorithm was used, and for the OD performance evaluation, position uncertainty, position differences between true and estimated orbits, and orbit overlap precision according to various ground supporting conditions were investigated. Orbit prediction accuracy variations due to ground tracking conditions were also demonstrated. This study provides a guideline for selecting ground tracking support levels and preparing a backup plan for the KPLO lunar mission phase.

This paper analyzes delta-Vs to maintain an extremely low altitude on the Moon and investigates the possibilities of performing a CubeSat mission. To formulate the station-keeping (SK) problem at an extremely low altitude, current work has utilized real-flight performance proven software, the Systems Tool Kit Astrogator by Analytical Graphics Inc. With a high-fidelity force model, properties of SK maneuver delta-Vs to maintain an extremely low altitude are successfully derived with respect to different sets of reference orbits; of different altitudes as well as deadband limits. The effect of the degree and order selection of lunar gravitational harmonics on the overall SK maneuver strategy is also analyzed. Based on the derived SK maneuver delta-V costs, the possibilities of performing a CubeSat mission are analyzed with the expected mission lifetime by applying the current flight-proven miniaturized propulsion system performances. Moreover, the lunar surface coverage as well as the orbital characteristics of a candidate reference orbit are discussed. As a result, it is concluded that an approximately 15-kg class CubeSat could maintain an orbit (30–50 km reference altitude having ±10 km deadband limits) around the Moon for 1–6 months and provide almost full coverage of the lunar surface.

In spite of a short history of only 30 years in space development, Korea has achieved outstanding space development capabilities, and became the 11th member of the “Space Club” in 2013 by launching its own satellites with its own launch vehicle from a local space center. With the successful development and operation of more than 10 earth-orbiting satellites since 1999, Korea is now rapidly expanding its own aspirations to outer space exploration. Unlike earth-orbiting missions, planetary missions are more demanding of well-rounded technological capabilities, specifically trajectory design, analysis, and navigation. Because of the importance of relevant technologies, the Korean astronautical society devoted significant efforts to secure these basic technologies from the early 2000s. This paper revisits the numerous efforts conducted to date, specifically regarding flight dynamics and navigation technology, to prepare for future upcoming planetary missions in Korea. However, sustained efforts are still required to realize such challenging planetary missions, and efforts to date will significantly advance the relevant Korean technological capabilities.

Domestic fruit wines, including apple, grape, Moru, and Korean black raspberry wines, contain a wide variety of phenolic compounds with different antioxidant activity. In this study, we established a simple and reliable on-line HPLC-ABTS assay system for determination of the antioxidative characteristics of fruit wines. The quantitative analytical assay of the antioxidative properties of fruit wines was carried out using an HPLC equipped with reverse-phase C18 column, employing acetonitrile and water as gradient mobile phase at a flow rate of 0.4 mL/min and a detection wavelength of UV 320 nm (1st detector) and UV 734 nm (2nd detector). Among fruit wines, Moru wine showed the highest total phenolics and flavonoids content, as well as radical scavenging activity. The differences in radical scavenging activities were attributed to the structural differences in phenolic compound contents. In addition, between on-line HPLC-ABTS analysis and ABTS assay using a spectrophotometric assay gave a coefficient of determination (R2) of 0.9527. All in all, the present study demonstrates that the established on-line HPLC-ABTS method is simple and reliable, and can thus be used for the determination of the antioxidative characteristics of fruit wines.

In this paper, we describe a case of using robot technology in child studies to examine children’s judgement and reasoning of the life phenomenon on boundary objects. In order to control the effects of the appearance of the robot, which children observe or interact directly with, on the children's judgement and reasoning of the life phenomenon, we developed a robot similar to human. Unit experimental scenarios representing biological and psychological properties were implemented based on control of robot's motion, speech, and facial expressions. Experimenters could combine these multiple unit scenarios in a cascade to implement various scenarios of the human-robot interaction. Considering that the experimenters are researchers of child studies, there was a need to develop a remote operation console that can be easily used by non-experts in the robot field. Using the developed robot platform, researchers of child studies could implement various scenarios by manipulating the biological and psychological properties of the robot based on their research hypothesis. As a result, we could clearly see the effects of robot's properties on children’s understanding about boundary object like robots.

The current study designs the mission orbit of the lunar CubeSat spacecraft to measure the lunar local magnetic anomaly. To perform this mission, the CubeSat will impact the lunar surface over the Reiner Gamma swirl on the Moon. Orbit analyses are conducted comprising ΔV and error propagation analysis for the CubeSat mission orbit. First, three possible orbit scenarios are presented in terms of the CubeSat’s impacting trajectories. For each scenario, it is important to achieve mission objectives with a minimum ΔV since the CubeSat is limited in size and cost. Therefore, the ΔV needed for the CubeSat to maneuver from the initial orbit toward the impacting trajectory is analyzed for each orbit scenario. In addition, error propagation analysis is performed for each scenario to evaluate how initial errors, such as position error, velocity error, and maneuver error, that occur when the CubeSat is separated from the lunar orbiter, eventually affect the final impact position. As a result, the current study adopts a CubeSat release from the circular orbit at 100 km altitude and an impact slope of 15°, among the possible impacting scenarios. For this scenario, the required ΔV is calculated as the result of the ΔV analysis. It can be used to practically make an estimate of this specific mission’s fuel budget. In addition, the current study suggests error constraints for ΔV for the mission.