• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.2
• /
• pp.156-163
• /
• 2013

The use of an error-correcting code is essential in communication systems where the channel is noisy. When channel coding parameters are unknown at a receiver side, decoding becomes difficult. To perform decoding without the channel coding information, we should estimate the parameters. In this paper, we introduce a method to reconstruct the generator polynomial of BCH(Bose-Chaudhuri-Hocquenghem) codes based on the idea that the generator polynomial is compose of minimal polynomials and BCH code is cyclic code. We present a probability compensation method to improve the reconstruction performance. This is based on the concept that a random data pattern can also be divisible by a minimal polynomial of the generator polynomial. And we confirm the performance improvement through an intensive computer simulation.

• Journal of Life Science
• /
• v.7 no.1
• /
• pp.17-23
• /
• 1997

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of maine pollutions by changes in cholinesterase activity of the flounder (Paralichthys olivaceus)in Yellow Sea of Korea. Acetylcholinesterase (AChE) activities in brain and muscle of cultured flounders in Yellow Sea were remarkably lower (40-50% and 40-55%, respectively)than those of wild flounder in Pohang (control) of East Sea, but AChE activities in brain and muscle of wild flounders in Yellow Sea were significantly lower(15-40% and 25-35%, respectively)than those of wild flounder in Pohang of East Sea. Butyrylcholinesterase(BChE) activities in barin and muscle of cultured flounders in Yellow Sea were remarkably lower(70-75% and 65-75%, respectively) than those of wild flounder in Pohang of East Sea, but BChE activities in barin and muscle of wild flounders in Yellow Sea were significantly lower (15-40%and 25-35%, respectively)than those of wild flounder in Pohang of East Sea. Lactate dehydrogenase (LDH) activities in serum of cultured flounders in Yellow Sea were significantly 10-50% higher than those of wild flounder in Pohang of East Sea, but LDH activities in serum of wild flounders in Yellow Sea were significantly 20-25% higher than those of wild flounder in Pohang of East Sea. It suggests that AChE and BChE activities in brain and muscle of cultured and wild flounders of Yellow Sea may be used as the most effective mean in a biochemical markers for diagnosis of pollutant effects by organophosphorus pesticides.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.3
• /
• pp.566-576
• /
• 2017

Key-value stores proved its superiority by being applied to various NoSQL databases such as Redis, Memcached. Lookup performance is important because key-value store applications performs more lookup than insert operations in most environments. However, in traditional applications, lookup may be slow because hash tables are constructed out of linked-list. Therefore, cuckoo hashing has been getting attention from the academia for constant lookup time, and bucketized cuckoo hashing (BCH) has been proposed since it can achieve high load factor. In this paper, we introduce Sorting Cuckoo which inserts data using insertion sort in BCH structure. Sorting Cuckoo determines the existence of a key with a relatively small memory access because data are sorted in each buckets. In particular, the higher memory load factor, the better lookup performance than BCH's. Experimental results show that Sorting Cuckoo has smaller memory access than BCH's as many as about 19 million (25%) in 10 million negative lookup operations (key is not in the table), about 4 million times (10%) in 10 million positive lookup operations (where it is) with load factor 95%.

• Journal of applied mathematics & informatics
• /
• v.5 no.1
• /
• pp.99-110
• /
• 1998

In this paper we study cyclic codes in $Z_m$. i.e., ideals in $Z_mG$, G afinite abelian group and we give a classification of such codes. We also sgtudy the minimum Hamming distance and the generalized Hamming weight of BCH codes over $Z_m$.

• Journal of Life Science
• /
• v.30 no.5
• /
• pp.452-459
• /
• 2020

This study was conducted to investigate the total lignin content and anti-oxidant activity in extracts of defatted sesame seeds (DSS) fermented with 15 strains of Bacillus subtilis. The anti-oxidant activities of DSS were analyzed both before and after fermentation. The total lignan content of the DSS extracts fermented with BCH3678 (1,613.8 mg/l) and BCH3572 (1,599.5 mg/l) were relatively high compared to other strains. Anti-oxidant activity was determined according to phenolic compound and flavonoid content and DPPH radical scavenging rate; the highest total phenolic compound content was provided by the DSS with SRCM103716 at 2,803.3 mg GAE/g which returned total flavonoid content of 1,553.1 mg/g as strong correlation of its anti-oxidant activity. The DSS extract fermented by SRCM103716 at 37℃ for 24 hr showed the highest DPPH scavenging rate at 66.5%. The fermented DSS extracts, regardless of strain, demonstrated higher anti-oxidative activity than the unfermented control, and these results suggest that such extracts could be useful as a potential source of bioactive compounds.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.1
• /
• pp.37-41
• /
• 1999

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in cholinesterase activity of the flounder (Paralichthys olivaceus) in tie South Sea of Korea. Aceflcholinesterase (AChE) activities in brain and muscle of cultured flounders in the South Sea were significantly lower ($10\~20\%$ and $12\~19\%$, respectively) than those of wild flounder in Pohang of the East Sea as a control. Buthrylcholinesterase (BChE) activites in brain and muscle of cultured flounders in the South Sea were also remarkably lower ($25\~40\%$ and $22\~35\%$, respectively) than those of wild flounder in Pohang. Lactate dehydrogenase (LDH) activites in serum of cultured flounders in South Sea were significantly higher ($10\~55\%$) than those of wild flounder in Pohang. It suggests that AChE, BChE and LDH activities of the flounders clould be used as effective biochemical markers for early warning of environmental damages caused by organophosphorus pesticides.

• KIPS Transactions on Computer and Communication Systems
• /
• v.8 no.6
• /
• pp.127-138
• /
• 2019

The data response speed is a critical issue of cloud services because it directly related to the user experience. As such, the in-memory database is widely adopted in many cloud-based applications for achieving fast data response. However, the current implementation of the in-memory database is mostly based on the linked list-based hash table which cannot guarantee the constant data response time. Thus, cuckoo hashing was introduced as an alternative solution, however, there is a disadvantage that only half of the allocated memory can be used for storing data. Subsequently, bucketized cuckoo hashing (BCH) improved the performance of cuckoo hashing in terms of memory efficiency but still cannot overcome the limitation that the insert overhead. In this paper, we propose a data management solution called Wall Cuckoo which aims to improve not only the insert performance but also lookup performance of BCH. The key idea of Wall Cuckoo is that separates the data among a bucket according to the different hash function be used. By doing so, the searching range among the bucket is narrowed down, thereby the amount of slot accesses required for the data lookup can be reduced. At the same time, the insert performance will be improved because the insert is following up the operation of the lookup. According to analysis, the expected value of slot access required for our Wall Cuckoo is less than that of BCH. We conducted experiments to show that Wall Cuckoo outperforms the BCH and Sorting Cuckoo in terms of the amount of slot access in lookup and insert operations and in different load factor (i.e., 10%-95%).

• Journal of Advanced Navigation Technology
• /
• v.5 no.2
• /
• pp.158-164
• /
• 2001

We presented a channel model for the inter vehicle radio link including the reflection from the road surface, side road vehicle and concrete wall. Then we theoretically derived the path loss and delay profile characteristics using the Ray tracing method efficiently analyzing millimeter wave or optic wave. Finally, we shown the improvement of propagation characteristics by diversity techniques, BCH coding and convolution coding techniques. At the result, MRC diversity techniques and BCH coding can't obtained PER = $10^{-6}$ which is considered to be data service criterion. But, we knew that Packet Error Rate Characteristic can obtained PER = $10^{-6}$, which is considered to be data service criterion, when convolution coding scheme are adopted in Rician fading.

• Journal of Advanced Navigation Technology
• /
• v.12 no.2
• /
• pp.115-121
• /
• 2008

In this paper, we analysis the error performance improvement of the FS MC-CDMA, whose information data are spread spectrum with direct sequences(DS), and each subband signal is transmitted using a subcarrier frequency, combining BCH code in Mobile communication channels which is characterized by Nakagami fading. The effect of co-channel interference on the block error performance is also studied in this paper. As a results of study, the coding techniques provides more efficient improvement than non-coding, but the coding techniques are required more band as many coding rate. Our study demonstrates that the system is combined coding techniques, the amount of improvement is capable of efficiently exploiting over the Nakagami fading.

• The KIPS Transactions:PartC
• /
• v.11C no.1
• /
• pp.109-114
• /
• 2004

A new code and its decoding scheme are proposed. With this code, we can correct and detect the errors in communication systems. To limit the runlength of data 0 and augment the minimum density of data 1, a (15, 7) BCH code is modified and an overall parity bit is added. The proposed code is a (16, 7) block code which has the bit clock signal regeneration capability and high error control capability. It is proved that the runlength of data 0 is less than or equal to 7, the density of data 1 is greater than or equal to 1/8, and the minimum Hamming distance is 6. The decoding error probability, the error detection probability and the correct decoding probability are presented for the proposed code. It is shown that the proposed code has better error control capability than the conventional schemes.