The wide-angle Polarimetric Camera (PolCam) onboard South Korea’s first lunar orbiter, Danuri, is a pioneering instrument designed to conduct the first global polarimetric and high-phase-angle survey of the Moon. Precise geometric calibration is critical for this mission, particularly due to PolCam’s highly oblique viewing geometry, which introduces significant topographic distortion. We present a comprehensive on-orbit geometric calibration that relies on 160,256 tie points derived from matching features between PolCam images and the well-orthorectified global map of the Kaguya Multiband Imager (MI). This dataset allows us to address two fundamental challenges: (1) the accurate reconstruction of the observation time for each line of an observation strip via a simple linear model, and (2) the refinement of the precise camera model, geometric model for PolCam optics. Our optimization method for these two challenges transforms the 2D image coordinates of identified features into 3D lunar coordinates and minimizes the reprojection error against the reference coordinates provided by the Kaguya MI map. From the refined observation time and camera model, we compute the precise longitude, latitude, and elevation of each pixel of an observed image. These estimated 3D coordinates are then used to generate orthorectified images, the final product of the geometric calibration. The resulting calibration achieves a geometric precision comparable to that of previous lunar orbiters and establishes the foundational framework necessary to produce geometrically-corrected data products of PolCam.
The Challan instrument is a solar full-disk imaging spectroscopic telescope planned to be installed at three sites with a 120-degree longitudinal difference, enabling continuous 24-hour observations of the Sun. It will take data every 2.5 min with a spatial resolution of 2–3′′ and a spectral resolving power (R) of >43,000 in Hα and Ca ii 8542 Å bands simultaneously. Challan is composed of two modules, each dedicated to a specific waveband. This modular design is beneficial in minimizing the scattered light and simplifying the structure and engineering. The primary scientific goal of Challan is to investigate solar flares and filament eruptions. It is also expected to detect small-scale events in the solar chromosphere. In 2025, Challan will be installed at the Big Bear Solar Observatory for test observational runs, followed by scientific runs in 2026.
Retailers procure private labels from several sources including national brand manufacturers, dedicated private label manufactures (often overseas or regional), and own manufacturing facilities.2 In the first case, the supplier utilizes its expertise and excess capacity to supply PLs. In the other two cases, the suppliers are dedicated to manufacturing PLs for single or multiple retailers. Consumers generally consider PLs as value substitutes of the corresponding national brands. As private labels become proliferated, more retailers are introducing premium PLs that oftentimes replace marginal national brands. It is natural to assume that the PL sourced from the excess capacity of the NB manufacturer is identical to the corresponding NB except for the branding and packaging. In this paper, we examine a retailer’s problem of tiered PL sourcing, in which a premium PL is supplied such a NB manufacturer (dual brander), and an economy PL is supplied by a dedicated PL supplier. We decompose the value of a product into three components: the NB’s brand equity, the retailer’s reputation, and the intrinsic quality of the NB. In this distribution channel, the NB’s wholesale and retail prices are determined by the traditional bilateral Nash game. However, the premium PL’s transfer price is determined through a profit-sharing negotiation between the channel members. Based on this game scenario, we build a model of price competition, given the quality, brand equity, and retailer reputation parameters, in order to examine strategic implications of the parameters to the equilibrium prices. In our bilateral pricing game, the NB manufacture and the retailer play a Nash pricing game, augmented by a profit sharing negotiation for the premium PL. In the negotiation process, the retailer’s negotiation power over the NB manufacture is reflected in the ratio of incremental profits from the premium PL. From an equilibrium-negotiation solution, we derive profit implications of each of the value components as well as the negotiation power of the retailer. Among several findings, the most interesting takeaway is that, even if the retailer holds a strong negotiation power, it is optimal for the retailer to leave some chips on the table for the NB manufacturer during the transfer pricing negotiation.
The Korea Astronomy and Space Science Institute plans to develop a coronagraph in collaboration with National Aeronautics and Space Administration (NASA) and to install it on the International Space Station (ISS). The coronagraph is an externally occulted one-stage coronagraph with a field of view from 3 to 15 solar radii. The observation wavelength is approximately 400~nm, where strong Fraunhofer absorption lines from the photosphere experience thermal broadening and Doppler shift through scattering by coronal electrons. Photometric filter observations around this band enable the estimation of 2D electron temperature and electron velocity distribution in the corona. Together with a high time cadence ($<$12~min) of corona images used to determine the geometric and kinematic parameters of coronal mass ejections, the coronagraph will yield the spatial distribution of electron density by measuring the polarized brightness. For the purpose of technical demonstration, we intend to observe the total solar eclipse in August 2017 with the filter system and to perform a stratospheric balloon experiment in 2019 with the engineering model of the coronagraph. The coronagraph is planned to be installed on the ISS in 2021 for addressing a number of questions (e.g., coronal heating and solar wind acceleration) that are both fundamental and practically important in the physics of the solar corona and of the heliosphere.
The effects of seed soaking treatment with the solutions of plant growth regulators IAA, GA3 and BAP on seed germination and shoot and bulb growth of Allium victorialis var. platyphyllum (Korean wild garlic) were determined. A significant variation in the seed germination rate was recorded at all treatments for various soaking periods. Maximum seed germination was obtained when seeds were soaked in IAA or GA3 solution at 200 mg L-1. The MAP treated seeds started to germinate after 3 months. Among treatments, IAA was found to be most effective in improving seed germination, but further seedling growth was not correlated to the soaking time. Seed soaking in IAA or GA3 solution enhanced further growth of seedlings compared with water control treatment. Shoot and bulb growth was highest in GA3 treatments.
Using a cosmological CDM simulation, we analyze the differences between the widely-used spin pa- rameters suggested by Peebles and Bullock. The dimensionless spin parameter λ proposed by Peebles is theoretically well-justified but includes an annoying term, the potential energy, which cannot be directly obtained from observations and is computationally expensive to calculate in numerical simulations. The Bullock’s spin parameter λ′ avoids this problem assuming the isothermal density profile of a virialized halo in the Newtonian potential model. However, we find that there exists a substantial discrepancy between λ and λ′ depending on the adopted potential model (Newtonian or Plummer) to calculate the halo total energy and that their redshift evolutions differ to each other significantly. Therefore, we introduce a new spin parameter, λ′′, which is simply designed to roughly recover the value of λ but to use the same halo quantities as used in λ′. If the Plummer potential is adopted, the λ′′ is related to the Bullock’s definition as λ′′ = 0.80 × (1 + z)−1/12λ′. Hence, the new spin parameter λ′′ distribution becomes consistent with a log-normal distribution frequently seen for the λ′ while its mean value is much closer to that of λ. On the other hand, in case of the Newtonian potential model, we obtain the relation of λ′′ = (1 + z)−1/8λ′; there is no significant difference at z = 0 as found by others but λ′ becomes more overestimated than λ or λ′′ at higher redshifts. We also investigate the dependence of halo spin parameters on halo mass and redshift. We clearly show that although the λ′ for small-mass halos with Mh < 2× 1012M⊙ seems redshift independent after z = 1, all the spin parameters explored, on the whole, show a stronger correlation with the increasing halo mass at higher redshifts.