• Convergence Security Journal
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• v.20 no.4
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• pp.91-101
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• 2020

We analyzed APT attack cases that occurred overseas in the past using a cyber kill chain model and a TTP model. As a result of the analysis, we found that the cyber kill chain model is effective in figuring out the overall outline, but is not suitable for establishing a specific defense strategy, however, TTP model is suitable to have a practical defense system. Based on these analysis results, it is suggested that defense technology development which is based on TTP model to build defense-in-depth system for preparing cyber attacks.

• Nutrition Research and Practice
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• v.1 no.4
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• pp.247-253
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• 2007

Alpha-tocopherol transfer protein (${\alpha}$-TTP) is a liver cytosolic transport protein that faciliates ${\alpha}$-tocopherol (${\alpha}$-T) transfer into liver secreted plasma lipoproteins. Genetic defects in ${\alpha}$-TTP, like dietary vitamin E deficiency, are associated with infertility, muscular weakness and neurological disorders. Both human and ${\alpha}$-TTP deficient (${\alpha}-TTP^{-/-}$) mice exhibit severe plasma and tissue vitamin E deficiency that can be attenuated by sufficient dietary ${\alpha}$-T supplementations. In this review, we summarize the literature concerning studies utilizing the ${\alpha}-TTP^{-/-}$ mice. Levels of vitamin E in the ${\alpha}-TTP^{-/-}$ mice do not appear to be directly related to the amounts of dietary ${\alpha}$-T or to the levels of ${\alpha}$-TTP protein in tissues. The ${\alpha}-TTP^{-/-}$ mice appear to present a good model for investigating the specific role of ${\alpha}$-T in tissue vitamin E metabolism. Furthermore, ${\alpha}-TTP^{-/-}$ mice appear to be useful to elucidate functions of ${\alpha}$-TTP beyond its well recognized functions of transferring ${\alpha}$-T from liver to plasma lipoprotein fractions.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.5
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• pp.518-528
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• 2000

Messages in distributed real-time systems are categorized into two groups: synchronous messages and asynchronous messages. Synchronous messages, such as sampled audio and image data,are generated periodically with delivery time constraints. Protocols should guarantee the end-to-enddeadlines for such messages. Asynchronous messages are non-periodic and may arrive in a randomway with no strict time constraints.In this paper, we propose TTP/C(timed token protocol with concession), an extension of TTPprotocol, to achieve higher timeliness guarantee for synchronous messages in distributed real-timesystems. In TTP/C, a node concedes the allocated bandwidth to other nodes with urgent synchronousmessages to be sent provided that the node has no urgent messages, TTP/C works very well evenif the synchronous messages are generated with some jittering by nodes. The simulation results showthe improved performance of TTP/C protocol for guaranteeing synchronous messages deadlinescomeared to the existing TTP protocols.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.338-340
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• 2003

Certified E-mail 프로토콜은 공정한 교환(fair exchange)을 보장하기 위하여 신뢰된 제 3자 (Trusted Third Party, TTP)톨 사용한다. 그러므로, Certified E-mail을 사용하는 유저들은 원격지의 TTP를 완전히 신뢰(fully-trust)해야 한다. 만약 TTP가 훼손되거나 유저와 공모하여 악위적인 행동을 한다면 Certified E-mail 프로토콜의 공정성(fairness)은 붕괴된다. 본 논문에서는 Threshold secret sharing을 사용하여 TTP의 신뢰성을 분산시킨 강건한 Certified E-mail 프로토콜을 제안한다. 분산된 TTP(Distributed TTP, DTTP)를 사용하므로써 유저가 공모하는 악위적인(malicious) TTP에 대한 공격을 막을 수 있으며 어느 한 DTTP가 훼손되더라도 전체 프로토콜에 영향을 주지 못한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.439-441
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• 2000

통신 기술의 발달은 컴퓨터를 활용한 정보 교환을 수월하게 만들었지만, 더불어 정보 유출의 가능성 또한 증가하였다. 특히 전자상거래와 같이 정보의 보호가 필요한 응용들도 급격히 활성화됨을 따라, 정보의 보안은 반드시 필요하며, 보안 서비스 중에서도 공정한 부인 봉쇄 서비스는 필수적이다. 기존에 제안된 부인 봉쇄 기법들은 보통 공정성을 위해 송.수신자는 중개자인 Trusted Third Party(TIP)를 두어 서로 통신한다. 하지만, 클라이언트수가 증가하면 중앙의 TTP에 네트웍 트래픽이 집중되어 효율적이지 못한다. 본 논문에서는 중앙 TTP에 집중되는 네트웍 트래픽량을 줄이기 위해 TTP를 분석시키는 새로운 부인봉쇄 프로토콜을 제시한다.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.287-294
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• 2014

The transcription factor E2F1 is active during G1 to S transition and is involved in the cell cycle and progression. A recent study reported that increased E2F1 is associated with DNA damage and tumor development in several tissues using transgenic models. Here, we show that E2F1 expression is regulated by tristetraprolin (TTP) in prostate cancer. Overexpression of TTP decreased the stability of E2F1 mRNA and the expression level of E2F1. In contrast, inhibition of TTP using siRNA increased the E2F1 expression. E2F1 mRNA contains three AREs within the 3'UTR, and TTP destabilized a luciferase mRNA that contained the E2F1 mRNA 3'UTR. Analyses of point mutants of the E2F1 mRNA 3'UTR demonstrated that ARE2 was mostly responsible for the TTP-mediated destabilization of E2F1 mRNA. RNA EMSA revealed that TTP binds directly to the E2F1 mRNA 3'UTR of ARE2. Moreover, treatment with siRNA against TTP increased the proliferation of PC3 human prostate cancer cells. Taken together, these results demonstrate that E2F1 mRNA is a physiological target of TTP and suggests that TTP controls proliferation as well as migration and invasion through the regulation of E2F1 mRNA stability.

• Environmental Mutagens and Carcinogens
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• v.8 no.1
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• pp.1-12
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• 1988

The effects of aphidicolin (APC), an inhibitor of DNA polymerase alpha, or 2', 3'-dideoxythymidine 5'-triphosphate (ddTTP), an inhibitor of DNA polymerase beta, on the repair of DNA damage induced by ethyl methanesulfonate (EMS) or bleomycin (BLM) were investigated in Chinese hamster ovary (CHO)-K1 cells. Three assays were employed in this study: unscheduled DNA synthesis, alkaline elution and alkaline sucrose gradient sedimentation. It was shown that APC or ddTTP inhibited DNA induced by EMS, and thus, the post-treatment with APC or ddTTP following EMS treatment was resulted in the more amount of unscheduled DNA synthesis, and the more accumulation of DNA single-stand breaks than the cells post-incubated without APC or ddTTP. While, in the BLM induced DNA repair, only ddTTP inhibited DNA repair induced by BLM. And thus, the groups post-incubated with or without APC after BLM treatment had the same value in the amount of unscheduled DNA synthesis and of DNA single-strand breaks, while post-treatment with ddTTP was resulted in the increased amount of unscheduled DNA synthesis and the increased DNA sin -strand breaks than the group without ddTTP. These results suggested that both of DNA polymerase $\alpha$ and $\beta$ participated in the repair of DNA damage induced by EMS, but in BLM-induced DNA repair, polymerase $\beta$ participated.ipated.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.596-602
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• 2007

Recently, many ECUs(Electronic Control Units) have been used to enhance the vehicle safety, which leads to a distributed real-time control system. The distributed real-time control system requires to reduce the network delay for dependable real-time performance. There are two different paradigms by which a network protocol operates: event-triggered and time-triggered. This paper focuses on implementation of a time-triggered protocol. i.e. TTP/C(Time-Triggered Protocol/class C). This paper presents a design method of TTP control network and performance evaluation of distributed real-time control system using TTP protocol.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.288-293
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• 2007

Thrombotic thrombocytopenic purpura(TTP) is a rare but life-threatening multi-system disorder characterized by the classic pentad of clinical features that includes fever, microangiopathic hemolytic anemia, thrombocytopenia, neurologic abnormalities and renal dysfunction. TTP has been rarely reported to simultaneously present with systemic lupus erythematosus (SLE). While it is important to distinguish between the two diseases of therapeutic implication, cases of concurrent TTP and SLE help to elucidate the pathophysiology that underlies each condition. We describe two adolescents with synchronous TTP and SLE, and review the literature.

• Molecules and Cells
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• v.41 no.7
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• pp.653-664
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• 2018

The RNA-binding protein tristetraprolin (TTP) binds to adenosine-uridine AU-rich elements in the 3'-untranslated region of messenger RNAs and facilitates rapid degradation of the target mRNAs. Therefore, it regulates the expression of multiple cancer and immunity-associated transcripts. Furthermore, a lack of TTP in cancer cells influences cancer progression and predicts poor survival. Although the functions of TTP on cancer cells have previously been researched, the mechanism of TTP on the interaction between cancer cells with their micro-environment remains undiscovered. In this study, we admed to determine the role of cancer cell TTP during the interaction between tumor and immune cells, specifically regulatory T cells (Tregs). We evaluate the capability of TTP to modulate the antitumor immunity of GC and explored the underlying mechanism. The overexpression of TTP in GC cells dramatically increased peripheral blood mononuclear lymphocyte (PBML) -mediated cytotoxicity against GC cells. Increased cytotoxicity against TTP-overexpressed GC cells by PBMLs was determined by Treg development and infiltration. Surprisingly, we found the stabilization of programmed death-ligand 1 (PD-L1) mRNA was declining while TTP was elevated. The PD-L1 protein level was reduced in TTP-abundant GC cells. PD-L1 gas been found to play a pivotal role in Treg development and functional maintenance in immune system. Taken together, our results suggest the overexpression of TTP in GC cells not only affects cell survival and apoptosis but also increases PBMLs -mediated cytotoxicity against GC cells to decelerate tumor progression. Moreover, we identified PD-L1 as a critical TTP-regulated factor that contributes to inhibiting antitumor immunity.