In this letter, we consider a one-way two-hop AF relaying scheme employing two independent Khatri-Rao space-time (KRST) codings at the source and relay nodes. The signals received at destination form ...a fourth-order tensor whose dimensions correspond to four signal diversities, and which satisfies a nested PARAFAC model. Exploiting this nested structure, we derive two matrix unfoldings expressed in terms of two Khatri-Rao products which are used to propose a closed-form semi-blind receiver allowing to jointly estimate the information symbols and the individual channels. A numerical analysis shows that this new receiver achieves a substantial computational complexity reduction over an iterative (ALS-based) semi-blind receiver, especially in presence of a great number of source and/or relay antennas.
In this paper, we propose a new MIMO communication system in a time-varying multipath environment, using a Khatri-Rao space-time (KRST) coding combined with a multiple Khatri-Rao product of symbol ...matrices (MKRSM). It is shown the signals received at the receiver form a tensor which satisfies a (M+2)-order nested PARAFAC model, where (M−1) denotes the number of symbol matrices considered for MKRSM coding. Such a generalization of the nested PARAFAC model to (M+N)-order tensors is first studied from a general point of view, with the discussion of some parameter estimation methods depending on the a priori knowledge on the model. Then, a semi-blind receiver composed of three stages, is developed for jointly estimating the transmitted symbols and the multipath parameters.
In the first stage, the transmitted symbols and a matrix unfolding of the effective channel including the fading coefficients and the steering matrices, are estimated using closed-form algorithms based on Khatri-Rao factorizations. In the second one, the channel estimation is refined by means of a simplified least-squares algorithm which takes the column orthonormality assumption on the coding matrix into account. In the third one, an alternating least-squares algorithm, combined with a rectification for the Vandermonde factors containing the spatial steering vectors at the transmitter and receiver sides, is applied to estimate the multipath parameters from the estimated channel. A complexity analysis is made for the receivers, and an expected Cramer-Rao bound related to channel estimation is established. Extensive Monte Carlo simulation results show that the semi-blind receiver which combines the channel estimation refinement with the rectification technique exhibit very interesting performance.
In this letter, we consider the dual-hop and three-hop multiple-input multiple-output (MIMO) sensor systems using multiple Khatri-Rao space-time (M-KRST) coding at the unmanned aerial vehicles and ...sensor nodes. According to the tensor structure of the communication links, the signals received at the fusion center form two separate nested tensors, which satisfy a nested parallel factor (PARAFAC) model and a nested parallel Tucker2 (PARATUCK2) model. Exploiting this nested structure, two semi-blind receivers based on an alternating least squares algorithm are formulated for a joint estimation of symbols and channels. Compared with the two-stage training method, simulation results demonstrate the superiority of the proposed semi-blind receivers in terms of normalized mean square error and bit error rate.
The danger of war with the Austro-Hungarian Monarchy led RegentAleksandar Karađorđević to make a decision on July 25th, 1914 to move the state leadership of the Kingdom of Serbia, the government, the ...National As-sembly, the state administration, and the diplomatic corps to the city of Niš. With the outbreak of World War I, Niš practically began to play the role of the wartime capital of Serbia, which would last until the autumn of 1915. With the Kingdom of Bulgaria joining the Central Powers and its entry into the war against Serbia, the position of the “wartime capital of Serbia” and its govern-ment institutions was endangered. Therefore, late September and October of 1915 saw the start of the process of the evacuation of all important government institutions from Niš. In that period, train compositions of medical supplies from the Red Cross warehouse were moved from Niš to Kruševac and Kraljevo. Foreign medical missions were evacuated as well. Intending to preserve and transport state and cultural treasures from Niš to Greece, on October 15th, Niko-la Pašić issued an order to organize the complete transport of the state archives, the most valuable books and manuscripts from libraries, as well as all exhibits from existing museums, along with the evacuation of the people. As the Bulgar-ian troops advanced from the east, the evacuation process went under way, and on October 26th, the employees of the War Ministry as well as foreign diplo-matic representatives and officials, around a thousand people, left the Red Cross Niš railway station. Despite the huge efforts of the Serbian Army in defending the country, and due to the truancy of allied forces eagerly awaited in Skopje and Niš, the German-Austro-Hungarian troops broke the Serbian resistance in the north and on November 6th Bulgarian troops advancing from the east en-tered the city of Niš.
Još o krstu i krštenju BAŠIĆ, Petar
Bogoslovska smotra,
07/2016, Volume:
86, Issue:
2
Paper
Open access
Autor u ovom članku kritički analizira neke pokušaje da se u hrvatskome jeziku, u govoru o prvom sakramentu, razjednače riječi krst (u značenju otajstvena zbiljnost, sakrament) i krštenje (u značenju ...slavljenje ili obred sakramenta) i zaključuje da to nije potrebno, pa čak ni moguće. Drži da je krštenje prikladnija riječ, a da riječ krst u ovom kontekstu nije potrebna.
Prešernova pesnitev Krst pri Savici sodi med temeljna dela slovenske književnosti. Pričujoča študija poskuša predstaviti nekaj temeljno različnih branj Prešernove poeme in neenakih orientacij v ...njenem notranjem dogajanju. Gre za štiri izhodiščno drugačna dojemanja pesnitve.
General, all mechanical systems consist of drive and driven groups, or
driving and driven machines. The connection of these machines is achieved by
special joints, machine elements - couplings. It is ...known that these joints
are often the weakest link in any mechanical system. Pursuant to a large set
of different drive and driven machines with different operating performance,
a large number of different coupling types were developed. However, a working
conditions of transport vehicles and other machinery require different mutual
positions of the driving and operating machinery. The name and concept of one
type of couplings is related to the pioneers in the design of these joints,
the famous Italian scientist Gerolamo Cardano (1501-1576) and Robert Hooke
(1635-1703). The designs of these couplings are passed through various stages
of development. The innovative designs development dynamics of these
couplings are shown in a separate chapter 3 of this study. Cardan joints
(cardan shafts) have a large range of applications in mechanical engineering
because of the capability of transferring the load and motion from one shaft
to another with different joint angle allowing, thereby, over time relative
movement. This movement can be angular and translational. The main indicators
of functional ability of cardan coupling are their service life and
reliability. The greatest influence on these indicators of functional ability
has the character of the linear load distribution on cardan joints rolling
parts. In order to shed some more light to the phenomena of linear load
distribution and correlation between the geometric characteristics of rolling
elements and the distribution of the linear load, analytical and numerical
models under appropriate assumptions are established in this study. The
obtained results shows, that with the standard (the existing) geometry of
rolling parts, the engagement of points in root of Cardan cross jurnal in the
load transfer is negligible due to very uneven linear load distribution. This
unfavorable distribution of the linear load can be reduced with an
appropriate combination of geometrical parameters of cardan cross rolling
parts. Greater improvement of linear load distribution, ordering the
appropriate shape reconstruction of cardan cross rolling parts. Therefore, a
detailed analysis of load distribution along the line of contact between
cardan cross pins and rolling parts – needles, was carried out in this study.
Appropriate geometric, analytical and numerical models are developed. Based
on the developed models, the correlation between the stress state in the
contact surfaces of rolling parts and the distribution of the linear load is
analyzed, and it is possible to optimize the geometrical parameters in terms
of uniformity of load distribution of Cardan joints component in contact.
Generalno posmatrano, svi mašinski sistemi se sastoje od pogonske i radne
grupe, odnosno pogonske i radne mašine. Spoj ovih mašina se ostvaruje
posebnim sklopovima, mašinskim elementima – spojnicama. Njihova osnovna
funkcija je prenošenje opterećenja i kretanja sa pogonske na radnu mašinu.
Poznato je da su spojevi najčešće najslabija karika u svakom mašinskom
sistemu. Saglasno velikom skupu različitih radnih i pogonskih mašina, sa
različitim radnim performansama, razvijen je veliki broj različitih spojnica.
Međutim, kod transportnih sredstava i drugih mašina, uslovi rada nalažu
različite međusobne položaje pogonske i radne mašine. Ime i pojam posebne
vrsta spojnica vezano je za pionire u konstrukciji ovih spojnica, slavnog
italijanskog naučnika Đerolama Kardana (Gerolamo Cardano, 1501-1576) i
Roberta Huka (Robert Hooke, 1635-1703). Konstrukciona rešenja ovih spojnica
prolazila su kroz različite faze razvoja. Dinamika razvoja konstrukcionih
rešenja ovih spojnica prikazane je u posebnom Poglavlju 3 ove disertacije.
Kardanove spojnice (kardanska vratila) su posebna vrsta mehanizama za
prenošenje obrtnog momenta, odnosno snage, koji spajaju vratila čije se ose
nalaze prostorno pod izvesnim stalnim ili u toku rada promenljivim uglom,
dozvoljavajući, pri tome, u toku vremena relativno pomeranje. Ovo pomeranje
može biti ugaono i translatorno. Glavni pokazatelji radne sposobnosti
kardanovih spojnica je njihov radni vek i stepen pouzdanosti. Najveći uticaj
na ove pokazatelje radne sposobnosti ima karakter raspodele linijskog
opterećenja kod spregnutih delova Kardanove spojnice. U cilju rasvetljavanja
fenomena raspodele linijskog opterećenja i sagledavanja stepena
kompatibilnosti između geometrijskih karakteristika spregnutih delova i
raspodela linijskih opterećenja, u disertaciji su formirani analintički i
numerički modeli pod odgovarajućim predpostavkama. Na osnovu dobijenih
rezultata je pokazano da je standardnom – postojećom geometrijom spregnutih
delova, angažovanje tačaka u korenu rukavca u prenošenju opterećenja zanemarljivo
malo, zbog izrazito neravnomerne raspodele linijskog opterećenja. Saglasno
ovoj raspodeli linijskog opterećenja i raspodela opterećenja na istovremeno
spregnute delove je neravnomerna. Ova nepovoljna raspodela linearnog
opterećenja, se može poboljšati odgovarajućom kombinacijom geometrijskih
parametara spregnutih korljajnih delova kadansovog krsta. Poboljšanje raspodele
linijskog opterećenja, zahteva odgovarajuću rekonstrukciju geometrije
kotrljajnih delova kardanovog krsta. U tom cilju, u ovoj Disertaciji je
sprovedena detaljna analiza raspodele opterećenja duž lijine kontakta rukavca
kardanovog krsta i kotrljajnih elemenata – iglica. Razvijeni su odgovarajući
geometrijski, analitički i numerički modeli, na osnovu kojih je moguće
izvršiti optimizaciju geometrijskih parametara radi postizanja što bolje
raspodele opterećenja kotrljajnih elemenata kardanovog krsta.
Otački nauk o krstu veoma je bogat, raznolik i slojevit. Svaki
je od onodobnih teologa o krstu razmišljao osobno. Nikakav
udžbenik nije krsni nauk stisnuo u krute okvire i tako dijelom
okamenio. Ipak ...se barem donekle mogu naznačiti određeni obrisi
krsnoga učenja kod crkvenih otaca. Krštenje se smatralo činom
kojim Bog iz milosti i milosrđa krštenomu oprašta grijeh. To se
odnosi na svaki grijeh: iskonski i osobni. Krsna voda snagom
Duha Svetoga čisti srce od svake grešne nečistoće i krštenomu
daruje djetinju dušu. Krštenje je djelo tako duboko i temeljito da
se smije nazvati novim stvaranjem i novim rođenjem. Kršćanin
doista i u pravome smislu nastaje u krštenju. Prije nije postojao.
S krštenjem se u ljudskoj duši oblikuje Božja slika koja ostaje za
svu vječnost. Razumije se da krštenje udjeljuje pravednost koja
je nevinost. Po krštenju kršteni postaju Božja djeca i sinovi Crkve.
U krštenju se kršteni prosvjetljuje. To je prosvjetljenje djelo vjere
koju kršteni kod krštenja izriče i prihvaća. Vjera odgoni tamu iz
duše i pruža svjetlo koje obasjava ovozemni život i prelazi u vječnu
svjetlost. Samo se kršteni smije u punoj mjeri nazivati vjernikom.
Krst je pečat utisnut u dušu. Pečat se više ne može izbrisati. Po
njemu se zna tko krštenoga brani i štiti te komu on pripada i komu
služi. Kršćanski se svakidašnji život upriličuje krsnome otajstvu.
Svi su kršteni po krštenju međusobno jednaki, braća su i sestre.
Prešernova "povest v verzih" Krst pri Savici (1836) ima v svojem tematskem središču tudi eksistencialni problem preloma iz poganstva v krščanstvo, utemeljen na svobodoumnem pojmovanju religioznosti. ...To pojmovanje pa je notranje diferencirano in razpeto med skepticizmom in nostalgijo. Skladno s tem sodi pesnitev po svoji žanrski pripadnosti med tiste romantične poeme, ki pomenijo dezintegracijo epa, ki pa ne poteka v smeri romana, temveč lirske epike.
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