• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.3
• /
• pp.25-32
• /
• 2019

The core of the block chain technology is solving the problem of agreement on double payment, and the PoW, PoS and DPoS algorithms used for this have been studied. PoW in-process proofs are consensus systems that require feasible efforts to prevent minor or malicious use of computing capabilities, such as sending spam e-mail or initiating denial of service (DoS) attacks. The proof of the PoS is made to solve the Nothing at stake problem as well as the energy waste of the proof of work (PoW) algorithm, and the decision of the sum of each node is decided according to the amount of money, not the calculation ability. DPoS is that a small number of authorized users maintain a trade consensus through a distributed network, whereas DPS provides consent authority to a small number of representatives, whereas PoS has consent authority to all users. If PoS is direct democracy, DPoS is indirect democracy. This study aims to contribute to the continuous development of the related field through the study of the algorithm of the block chain agreement.

• Kyungpook Mathematical Journal
• /
• v.54 no.4
• /
• pp.629-638
• /
• 2014

The concept of prime and weakly prime ideal in semigroups has been introduced by G. Szasz [4]. In this paper, we define the involution in po-${\Gamma}$-semigroups, then we extend some results on prime, semiprime and weakly prime ideals to the involution po-${\Gamma}$-semigroup S. Also, we characterize intra-regular involution po-${\Gamma}$-semigroups. We establish that in the involution po-${\Gamma}$-semigroup S such that the involution preserves the order, an ideal of S is prime if and only if it is both weakly prime and semiprime and if S is commutative, then the prime and weakly prime ideals of S coincide. Finally, we prove that if S is a po-${\Gamma}$-semigroup with order preserving involution, then the ideals of S are prime if and only if S is intra-regular.

• ETRI Journal
• /
• v.37 no.6
• /
• pp.1120-1128
• /
• 2015

We propose a pseudo optical N-level pulse-amplitude modulation (PO PAM-N) signal using a few externally-modulated lasers (EMLs) operating at different wavelengths, which is suitable for upgrading the transmission speed over an optical link of < 10 km single-mode fiber with low-cost components. To compare a PO PAM-N signal with that of a standard optical PAM-N signal, we perform experiments for evaluating the performance of a 51.56-Gb/s PO PAM-4 signal and standard 51.56-Gb/s optical PAM-4 signal. The receiver sensitivity (at $BER=10^{-5}$) of the PO PAM-4 signal is 1.5 dB better than the receiver sensitivity of a standard optical PAM-4 signal. We also investigate the feasibility of PO PAM-N (N = 4, 8, and 16) signals operating at 103.12 Gb/s, considering relative intensity noise, timing jitter, extinction ratio (ER) of EMLs, and dispersion. From the results, a PO PAM-8 signal performs better than PO PAM-4 and PO PAM-16 signals at 103.12 Gb/s. Finally, we suggest a timing control method to suppress the effect of dispersion in a PO PAM-N signal. We show that the tolerance to dispersion of a 103.12-Gb/s PO PAM-8 signal can be improved to ${\pm}40ps/nm$ by applying a proposed scheme.

• Korean Journal of Mathematics
• /
• v.8 no.1
• /
• pp.43-45
• /
• 2000

In this paper, we give the characterization of a left (right) filter of $po$-semigroups.

• International Journal of Computer Science & Network Security
• /
• v.24 no.6
• /
• pp.41-48
• /
• 2024

Existing PoS (Point of Sale) based payment frameworks are vulnerable as the Payment Application's integrity in the smart phone and PoS are compromised, vulnerable to reverse engineering attacks. In addition to these existing PoS (Point of Sale) based payment frameworks do not perform point-to-point encryption and do not ensure communication security. We propose a Smart and Secure PoS (SSPoS) Framework which overcomes these attacks. Our proposed SSPoS framework ensures point-to-point encryption (P2PE), Application hardening and Application wrapping. SSPoS framework overcomes repackaging attacks. SSPoS framework has very less communication and computation cost. SSPoS framework also addresses Heartbleed vulnerability. SSPoS protocol is successfully verified using Burrows-Abadi-Needham (BAN) logic, so it ensures all the security properties. SSPoS is threat modeled and implemented successfully.

• Microbiology and Biotechnology Letters
• /
• v.5 no.3
• /
• pp.153-158
• /
• 1977

These experiments were conducted to investigate the condition of the production and the heat resistance of the acid protease by Rhizopus japonicus S-62. The results obtained were as follows: 1) The optimum concentrations of sucrose, yeast, ammonium chloride and sodium phosphate monobasic added to the wheat bran medium in the acid protease production were 0.5％, 2.0％, 0.4％, and 0.4％, respectively. 2) KH$_2$PO$_4$ and NaH$_2$PO$_4$ were the most effective as the heat resistant agents. 3) When the enzyme solutions added with KH$_2$PO$_4$ and NaH$_2$PO$_4$ to the concentration of 2％ were heated for 10 min, at 50$^{\circ}C$, their residual activities were 100％, respectively. 4) The heat resistant effects of KH$_2$PO$_4$ and NaH$_2$PO$_4$ were not observed almost above 55$^{\circ}C$.

• Review of KIISC
• /
• v.28 no.3
• /
• pp.18-25
• /
• 2018

최근 블록체인 기술을 응용한 가상화폐에 대한 관심이 높아지면서 자본금이 많지 않은 사람들도 블록체인 네트워크에 참여하기 시작했다. 가장 유명한 가상화폐인 비트코인이 채택한 PoW 방식은 고성능 하드웨어의 과열된 열풍을 불어왔고 PoS 방식은 기존 지분이 많은 참여자들이 많이 존재하여 소수의 자본금을 가진 신규 참여자들이 네트워크에 새로 참여하기 어려운 환경이다. 따라서 본 논문에서는 기존 블록체인 증명방식인 PoW, PoS 방식보다 네트워크 참여를 위한 자본금이 적고 신규로 참여하더라도 리스크가 적은 PoP(Proof-of-Probability) 방식을 소개한다. PoP 방식은 블록을 생성할 시 실제 암호화된 해쉬와 수많은 가짜 해쉬를 각 노드들이 정렬하여 진짜 해쉬를 복호화하여 찾은 노드가 블록을 생성하는 방식이다. 또한 1개의 해쉬를 복호화하여 검증받을 때 1분의 대기시간을 두어 과열된 컴퓨팅파워 경쟁을 제한한다. 지분(Stake)이 많을수록 블록을 생성할 확률은 높아지지만 이는 PoS 방식처럼 절대적이지 않다. 이 방식을 이용한다면 지분을 많이 가진 유효성 검증자(Validators)에 의한 집중화를 피하며 블록체인 네트워크에 참여하려는 진입장벽도 낮출 수 있을 것 이다.

• Journal of Navigation and Port Research
• /
• v.38 no.6
• /
• pp.629-636
• /
• 2014

To minimize secondary damages from marine environment pollution resulting from marine accidents, International Maritime Organization(IMO) adopted "Guidelines on Places of Refuge(POR) for ships in need of assistance" as Resolution A.949(23) in it is 23rd General Assembly in 2003 and recommends Parties to the Organization designate PoR. This resolution suggests that they establish a "Decision-Making process" so as to provide reasonable PoR when disabled ships request use of PoR. Korea has not been performed introduce a PoR system in the country. Therefore, there is no decision-making process to deal with ships which need PoR. When Korea implements the PoR system in the future, the nation should establish a Decision-Making process to provide reasonable PoR in case ships in need of assistance request for PoR. In order to present what should be considered in the process of establishing a Decision-Making process for PoR in Korea in the future, in this study presents matters which should be considered in the process of founding PoR Decision-Making processes. When Korea tries to conduct POR system so that other countries' PoR Decision-Making process and the relating process of IMO and REMPEC (Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea) were investigated and analyzed. In addition, in times of marine accident in Korea's sea areas, Korea's action manuals for marine accident which regulates management for an accident is analyzed and articles will be presented to be taken into account during establishing final PoR Decision-Making process.

• Journal of architectural history
• /
• v.22 no.4
• /
• pp.7-18
• /
• 2013

Integrated-Salmi can be suggested as a character of Da-po type Kong-po in Korea's traditional architecture. However, only few studies are made on this subject yet. This study is to investigate the integration process of Salmi through cases of certain Kong-po which have the same number of inner and outer Chul-mok and are also known to precede in time. The results of the study are like below. First, Integrated-Salmi is more dominant in inner and outer 3 Chul-mok Kong-po than in inner and outer 2 Chul-mok Kong-po. Second, While inner and outer 2 Chul-mok prevail in Yeong-nam region, inner and outer 3 Chul-mok prevail in Ho-nam region. Third, integrated Salmi of Inner and outer 3 Chul-mok, first appeared in internal Jusangpo to be carried over to internal Juganpo then eventually to outer Salmi. Fourth, the reason why integrated form precede in internal salmi of inner and outer 3 Chul-mok Kong-po is due to 2 main factors. First of which is the impact of integrated Boaji that developed in Da-po type since the early 16th century. The second factor is downward expansion of Cho-gak's Boaji which was adopted to cope with disorders made in structure of Chum-Cha, due to inner and outer 3 Chul-mok type buddhist temples' wide reconstruction throughout Jeolla region following the Japanese invasion of Korea in 1592. This study is to disclose the regularity of development process of Salmi's Cho-gak(草刻) which is a characteristic of Korea's Da-po type Kong-po.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.18 no.6
• /
• pp.248-252
• /
• 2008

To get a fine $LiFePO_4$ powder with high electrical conductivity, the influences of doping of aliovalent elements(Cr+B and Cr+Al) on electrical conductivity and of heat treatment conditions on particle size of the doped powders were studied. Two kinds of the doped powders $LiFe_{0.965}Cr_{0.03}B_{0.005}PO_4$ and $LiFe_{0.065}Cr_{0.03}Al_{0.005}PO_4$ were synthesized using mechanochemical milling and subsequent heat treatment at $675{\sim}750^{\circ}C$ for $5{\sim}10\;h$. The doping enhanced grain growth and electrical conductivity. The electrical conductivity at $30^{\circ}C$ was $1{\times}10^{-8}S/cm$ in the doped with Cr and Al, and $5{\times}10^{-10}S/cm$ in the undoped one.