WISEA J041451.67–585456.7 and WISEA J181006.18–101000.5: The First Extreme T-type Subdwarfs?

We present the discoveries of WISEA J041451.67−585456.7 and WISEA J181006.18−101000.5, two low-temperature (1200–1400 K), high proper motion T-type subdwarfs. Both objects were discovered via their high proper motion (>0".5 yr⁻¹); WISEA J181006.18−101000.5 as part of the NEOWISE proper motion survey and WISEA J041451.67−585456.7 as part of the citizen science project Backyard Worlds; Planet 9. We have confirmed both as brown dwarfs with follow-up near-infrared spectroscopy. Their spectra and near-infrared colors are unique among known brown dwarfs, with some colors consistent with L-type brown dwarfs and other colors resembling those of the latest-type T dwarfs. While no forward model consistently reproduces the features seen in their near-infrared spectra, the closest matches suggest very low metallicities ([Fe/H] ⩽ −1), making these objects likely the first examples of extreme subdwarfs of the T spectral class (esdT). WISEA J041451.67−585456.7 and WISEA J181006.18−101000.5 are found to be part of a small population of objects that occupy the "substellar transition zone," and have the lowest masses and effective temperatures of all objects in this group

WISEA J041451.67–585456.7 and WISEA J181006.18–101000.5: The First Extreme T-type Subdwarfs?

We present the discoveries of WISEA J041451.67−585456.7 and WISEA J181006.18−101000.5, two low-temperature (1200–1400 K), high proper motion T-type subdwarfs. Both objects were discovered via their high proper motion (>0".5 yr⁻¹); WISEA J181006.18−101000.5 as part of the NEOWISE proper motion survey and WISEA J041451.67−585456.7 as part of the citizen science project Backyard Worlds; Planet 9. We have confirmed both as brown dwarfs with follow-up near-infrared spectroscopy. Their spectra and near-infrared colors are unique among known brown dwarfs, with some colors consistent with L-type brown dwarfs and other colors resembling those of the latest-type T dwarfs. While no forward model consistently reproduces the features seen in their near-infrared spectra, the closest matches suggest very low metallicities ([Fe/H] ⩽ −1), making these objects likely the first examples of extreme subdwarfs of the T spectral class (esdT). WISEA J041451.67−585456.7 and WISEA J181006.18−101000.5 are found to be part of a small population of objects that occupy the "substellar transition zone," and have the lowest masses and effective temperatures of all objects in this group

Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project

We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multiepoch Wide-field Infrared Survey Explorer (WISE) images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]–[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1'' yr⁻¹; our fastest-moving discovery is WISEA J155349.96+693355.2 (μ ≈ 2.”15 yr⁻¹), a possible T-type subdwarf. We also report a newly discovered wide-separation (~400 au) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5 5 projected separation (~8700 au if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf

Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project

We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multi-epoch WISE images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]-[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1"/yr; our fastest-moving discovery is WISEA J155349.96+693355.2 (total motion ~2.15"/yr), a possible T type subdwarf. We also report a newly discovered wide-separation (~400 AU) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5.5' projected separation (~8,700 AU if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf.Comment: accepted for publication in The Astrophysical Journa

Uuden kulunvalvontajärjestelmän suunnittelu konesaliympäristössä

Kulunvalvonta on tärkeä osa konesaliympäristöjen fyysistä tietoturvaa. Tällä turvataan yrityksien sekä asiak-kaiden kriittiset tiedot ja laitteistot. Kulunvalvonnalla tarkoitetaan alueen valvontaa erilaisilla menetelmillä. Näitä voivat olla teknisillä laitteistolla tai henkilöiden toimesta suoritettava vartiointi. Teknisellä laitteistolla voidaan viitata esimerkiksi erilaisiin sensoreihin ja lukijoihin. Kulunvalvonnan tarve voidaan kartoittaa eri-laisilla riskienhallinta menetelmillä sekä tietoturvariskien arvioinnilla. Näillä keinoilla voidaan määrittää, minkälaista laitteistoa kulunvalvonnassa käytetään. Tämän perusteella voidaan tehdä suunnitelma, miten eri kulunvalvonnan vastatoimia käytetään toistensa kanssa yhdessä. Tällä tavoin saadaan täydellinen kulunval-vonta, jolla alue turvataan tehokkaasti. Opinnäytetyön tavoitteena oli tutustua kulunvalvonnan käytäntöihin sekä käsitteisiin. Tämän lisäksi toteu-tettiin kulunvalvontajärjestelmien arviointi, joka toimi opinnäytetyön käytännön osana. Työ toteutettiin Kajaanin ammattikorkeakoulun päättötyönä. Tämän lisäksi työ suoritettiin yhteistyössä konesaliympäristön omistavan toimeksiantajayrityksen kanssa. He tarvitsivat suunnitelman ja ehdotuksen uuteen kulunvalvon-tajärjestelmään. Työn lopputuloksena saatiin toimiva teoriaosuus kulunvalvonnan käytännöistä sekä käsit-teistä ja käytännön osuutena arviointi kahdesta johtavasta kulunvalvontajärjestelmistä. Arviointikriteereinä käytettiin toimeksiantajayrityksen poistuvan järjestelmän asettamia tarpeita sekä uudistuksia, joita he halu-sivat järjestelmältä. Työssä tutustuttiin kulunvalvonnan eri osa-alueisiin käyttämällä lähteitä niin internetistä, kuin myös kirjallisuudesta. Arviointi suoritettiin käyttämällä järjestelmien dokumentointia. Lopputuloksena saatiin suositus järjestelmästä, johon toimeksiantajayritys voi siirtyä.Access control is an important part of the physical security of data center environments. This secures criti-cal data and hardware for businesses and customers. Access control refers to the monitoring of an area using various methods. These may include technical equipment or guarding done by humans. Technical equipment can refer, for example, to various sensors and readers. The need for access control can be identified through different types of risk management methods and security risk assessments. These methods can be used to determine the type of hardware to be used for access control. Based on this, a plan can be made to use the different access control countermeasures in combination with each other. In this way, a complete access control system can be established to effectively secure the area. The aim of the thesis was to familiarize the reader with the practices and concepts of access control. In addition, an evaluation of access control systems was carried out as a practical part of the thesis. The work was carried out as a final project at Kajaani University of Applied Sciences. In addition to this, the work was done in cooperation with a client company that owns the data center environment. They needed a plan and proposal for a new access control system that would replace the current system in use. The result was a working theoretical part on access control practices and concepts and a practical part where an evalua-tion of two leading access control systems was done. The evaluation criteria were based on the needs of the client company's existing system and the reforms they wanted from the new system. The work ex-plored the different aspects of access control using sources from the internet as well as from literature. The evaluation was carried out using documentation of the systems. The result was a recommendation for a system that the client company could transfer to

Eye-Controlled Region of Interest HEVC Encoding

This paper presents a demonstrator setup for real-time HEVC encoding with gaze-based region of interest (ROI) detection. This proof-of-concept system is built on Kvazaar open-source HEVC encoder and Pupil eye tracking glasses. The gaze data is used to extract the ROI from live video and the ROI is encoded with higher quality than non-ROI regions. This demonstration illustrates that performing HEVC encoding with non-uniform quality reduces bit rate by 40-90% and complexity by 10-35% over that of the conventional approaches with negligible to minor deterioration in subjective quality.acceptedVersionPeer reviewe

Comparative Rate-Distortion-Complexity Analysis of VVC and HEVC Video Codecs

Versatile Video Coding (VVC/H.266) is the next-generation international video coding standard and a successor to the widespread High Efficiency Video Coding (HEVC/H.265). This paper analyzes the rate-distortion-complexity characteristics of the VVC reference software (VTM10.0) by using HEVC reference software (HM16.22) as an anchor. In this independent study, the rate-distortion performance of VTM was benchmarked against HM with the objective PSNR, SSIM, and VMAF quality metrics and the associated encoder and decoder complexities were profiled at function level using Intel VTune Profiler on Intel Xeon E5-2699 v4 22-core processors. For a fair comparison, all our experiments were conducted under the VTM common test conditions (CTC) that define 10-bit configurations of the VTM codec for the addressed All Intra (AI), Random Access (RA), and Low Delay B (LB) conditions. The VTM CTC test set was also extended with complementary 4K UHD sequences to elaborate RD characteristics with higher resolutions. According to our evaluations, VTM improves the average coding efficiency over HM, depending on quality metric, by 23.0–23.9% under the AI condition, 33.1–36.6% under the RA condition, and 26.7–29.5% under the LB condition. However, the coding gain of VTM comes with 34.0×, 8.8×, and 7.5× encoding complexity over that of HM under the AI, RA, and LB conditions, respectively. The corresponding overhead of the VTM decoder stays steady at 1.8× across all conditions. This study also pinpoints the most complex parts of the VTM codec and discusses practical implementation aspects of prospective real-time VVC encoders and decoders.publishedVersionPeer reviewe