Objectives:Th preservatives benzalkonium chlorid (BZC) and potassium sorbate (PS) are widely u ed, not only for na al drops, but also for eyedrops and co metics. How ver, ther e have been many case reports that consider lesions such as d ermatitis or conjunctivitis to b e the r esults of irritation induced by BZC or PS. Methods: We evaluated the histological change aft er the long-term administration ofBZC or PS on rat nasa l respiratory mucosa. Forty rats were us d for the BZC group and 40 rats for PS group. Anima ls in ach group were divid d into four subgroups. Th first subgroup received a lowconcentration preservative solution that was commonly u · d for nasal sprays. The second subgroup received a high-concentration preservative solution that was reported to induce d ermatitis in humans. The third and fourth subgroups received a s teroid .mixed pr servntive solution of low and high concentrations, respectively. The control group was administrnt d normal saline. After each group r eceived 1, 2, and 4 we k s of topical administration, the symptomatic and histological changes on H&E stain were obrv d. Results: Sneezing and nasal rubbing with for I gs were observ din almo tall subgroups by the s . venth day of treatm nt. The pr servatives induced nasal I sion , including intraepithelial glandular formation, inflammatory cell infiltra tion, vascular hyp rplasia, and edematous change. The symptomatic and hi tological chang s wea· pronounced with the prolonged duration of administration. Similar r esults w r ob rv d in the ste roid mixed-solution groups. In the PS st roid mixed-olution group, howeve. r, symptom a nd nasal lesions were reduced with the prolonged duration of administration. Conclusion: ItFrom Lhe D pnrtmenL ofOLolnryngology-Hoad nnd Neck Surgery, ollege of M. dicin , Th atholic Univ rsity of Kor a, Seoul , Kor

As a solution to protect and defend a system against inside attacks, many intrusion detection systems (IDSs) have been developed to identify and react to them for protecting a system. However, the core idea of an IDS is a reactive mechanism in nature even though it detects intrusions which have already been in the system. Hence, the reactive mechanisms would be way behind and not effective for the actions taken by agile and smart attackers. Due to the inherent limitation of an IDS with the reactive nature, intrusion prevention systems (IPSs) have been developed to thwart potential attackers and/or mitigate the impact of the intrusions before they penetrate into the system. In this chapter, we introduce an integrated defense mechanism to achieve intrusion prevention in a software-defined Internetof-Things (IoT) network by leveraging the technologies of cyberdeception (i.e., a decoy system) and moving target defense, namely MTD (i.e., network topology shuffling). In addition, we validate their effectiveness and efficiency based on the devised graphical security model (GSM)-based evaluation framework. To develop an adaptive, proactive intrusion prevention mechanism, we employed fitness functions based on the genetic algorithm in order to identify an optimal network topology where a network topology can be shuffled based on the detected level of the system vulnerability. Our simulation results show that GA-based shuffling schemes outperform random shuffling schemes in terms of the number of attack paths toward decoy targets. In addition, we observe that there exists a tradeoff between the system lifetime (i.e., mean time to security failure) and the defense cost introduced by the proposed MTD technique for fixed and adaptive shuffling schemes. That is, a fixed GA-based shuffling can achieve higher MTTSF with more cost while an adaptive GA-based shuffling obtains less MTTSF with less cost. Introduction Research Goal & ContributionsThis work aims to propose an integrated proactive defense based on intrusion preventive mechanisms, such as cyberdeception and MTD techniques, to minimize the impact of potential attackers trying to penetrate into IoT systems via multiple entries. We make the following key contributions in this book chapter:  We developed an integrated proactive defense system by proposing an adaptive MTD technique by shuffling a network topology where a network consists of both decoy nodes and real nodes. As decoy nodes are the part of a decoy system,

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