A s a c om pl e men t t o da ta d edupli cat ion , de lta c om p ress i on fu r-
t he r r edu c es t h e dat a vo l u m e by c o m pr e ssi n g n o n - dup li c a t e
d ata chunk s r e l a t iv e to t h e i r s i m il a r chunk s (bas e chunk s).
H ow ever, ex is t i n g p o s t - d e dup li c a t i o n d e l t a c o m pr e ssi o n a p-
p ro a ches fo r bac kup s t or ag e e i t h e r su ffe r f ro m t h e l ow s i m -
il a r i t y b e twee n m any de te c ted c hun ks o r m i ss so me po t e n -
t i a l s i m il a r c hunks , o r su ffer f r om l ow (ba ckup and r es t ore )
th r oug hpu t du e t o extr a I/ Os f or r e a d i n g b a se c hun ks o r a dd
a dd i t i on a l s e r v i c e - d i s r up t ive op e r a t i on s to b a ck up s ys t em s.
I n t h i s pa p e r, w e pr opo se L oop D e l t a t o a dd ress the above -
m e n t i on e d prob l e m s by an e nha nced em b e ddi n g d e l t a c o m p -
r e ss i on sc heme i n d e dup li c a t i on i n a non - i n t ru s ive way. T h e
e nha nce d d elt a c o mpr ess ion s che m e co m b in e s f our key t e c h -
ni qu e s : (1) du a l - l o c a li t y - b a s e d s i m il a r i t y t r a c k i n g to d e t ect
po t e n t i a l si m il a r chun k s b y e x p l o i t i n g both l o g i c a l and ph y -
s i c a l l o c a li t y, ( 2 ) l o c a li t y - a wa r e pr e f e t c h i n g to pr efe tc h ba se
c hun ks to a vo i d ex t ra I/ Os fo r r e a d i n g ba s e chun ks on t h e
w r i t e p at h , (3) c a che -aware fil t e r to avo i d ext r a I/Os f or b a se
c hunk s on t he read p at h, a nd (4) i nver sed de l ta co mpressi on t o
perf orm de lt a co mpress i o n fo r d at a chunk s t hat a re o th e r wi se
f o r b i dd e n to s er ve as ba se c hunk s by r ew r i t i n g t e c hn i qu e s
d e s i g n e d t o i m p r ove r es t o re pe rf o rma nc e.
E x p e r i m e n t a l re su lts indi ca te t hat L oop D e l t a i ncr ea se s t he
c o m pr e ss i o n r a t i o by 1 .2410 .97 t i m e s on t op of d e dup li c a -
t i on , wi t hou t no t a b l y a ffe c t i n g th e ba ck up th rou ghpu t, a nd i t
i m p r ove s t he res to re p er fo r m an ce b y 1.23.57 t i m e
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N -Vinyl and N -Aryl Hydroxypyridinium Ions: Charge-Activated Catalysts with Electron-Withdrawing Groups
- Award ID(s):
- 1665392
- NSF-PAR ID:
- 10191309
- Date Published:
- Journal Name:
- The Journal of Organic Chemistry
- Volume:
- 85
- Issue:
- 9
- ISSN:
- 0022-3263
- Page Range / eLocation ID:
- 6017 to 6026
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract We describe convenient preparations of
N ,N′ ‐dialkyl‐1,3‐propanedialdiminium chlorides,N ,N′ ‐dialkyl‐1,3‐propanedialdimines, and lithiumN ,N′ ‐dialkyl‐1,3‐propanedialdiminates in which the alkyl groups are methyl, ethyl, isopropyl, ortert ‐butyl. For the dialdiminium salts, the N2C3backbone is always in thetrans‐ s‐trans configuration. Three isomers are present in solution except for thetert ‐butyl compound, for which only two isomers are present; increasing the steric bulk of theN ‐alkyl substituents shifts the equilibrium away from the (Z ,Z ) isomer in favor of the (E ,Z ), and (E ,E ) isomers. For the neutral dialdimines, crystal structures show that the methyl and isopropyl compounds adopt the (E ,Z ) form, whereas thetert ‐butyl compound is in the (E ,E ) form. In aprotic solvents all four dialdimines (as well as the lithium dialdiminate salts) adoptcis‐ s‐cis conformations in which there presumably is either an intramolecular hydrogen bond (or a lithium cation) between the two nitrogen atoms.
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.joc.0c00498
