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This study addresses the critical challenge of developing lightweight, flexible soundproofing materials for contemporary applications by introducing an innovative Flexible Soundproofing Metapanel (FSM). The FSM represents a significant advancement in acoustic metamaterial design, engineered to attenuate noise within the 2000–5000 Hz range—a frequency band associated with significant human auditory discomfort. The FSM’s novel structure, comprising a box-shaped frame and vibrating membrane, was optimized through rigorous finite element analysis and subsequently validated via comprehensive open field tests for enclosure-type soundproofing. Our results demonstrate that the FSM, featuring an optimized configuration of urethane rubber (Young’s modulus 6.5 MPa) and precisely tuned unit cell dimensions, significantly outperforms conventional mass-law-based materials in sound insulation efficacy across target frequencies. The FSM exhibited superior soundproofing performance across a broad spectrum of frequency bands, with particularly remarkable results in the crucial 2000–5000 Hz range. Its inherent flexibility enables applications to diverse surface geometries, substantially enhancing its practical utility. This research contributes substantially to the rapidly evolving field of acoustic metamaterials, offering a promising solution for noise control in applications where weight and spatial constraints are critical factors.

This article examines the tensions surrounding the opening of Seoul to foreign trade and residence and how mixed residence and extraterritoriality played a decisive role in the boundaries of residence in Seoul as well as the boundaries of jurisdiction and citizenship in Korea from 1876 to 1910. Different from most capital cities in East Asia, Seoul opened in 1882 as a city of mixed residence with no foreign settlements established exclusively for foreign residents. As a result, the entire space inside the walls became an arena where multiple extraterritorialities directly challenged the sovereignty of the Korean state. It was against this backdrop of imperial powers’ growing presences and their attempts to make Seoul into an extraterritorial space that the newly established Taehan Empire strove to refashion Seoul into the imperial capital Hwangsŏng, as a means to reinsert its power into the capital’s space and residents. Despite its efforts, however, this article shows that the Korean government was losing its grip on both the capital’s space and residents, as a growing number of opportunistic Koreans evaded Korean jurisdiction by taking advantage of extraterritoriality or obtaining foreign citizenship.

This paper measures the technical inefficiency and the shadow price of Korean fossil-fuel generation companies (GENCOs) between 2001 and 2016 at the firm-level. To obtain robust empirical results, this study employs both commonly used deterministic and stochastic estimation methods. The empirical results are as follows: the inefficiency estimates are approximately 0.09 (deterministic) and 0.08 (stochastic); the estimates of CO 2 shadow price, in KRW/tCO 2 , are 82,758 (deterministic) and 49,830 (stochastic), which shows high volatility in the annual average shadow price. In addition, we find that the results of the deterministic method without any random errors show a large variation in the trends of technical inefficiency and shadow price, while the stochastic method with random errors yields only moderate volatility. Our empirical results are expected to assist policymakers in determining how much potential mitigation can be achieved through improved efficiency, and the range of the CO 2 shadow price will contribute to more efficient policy tools.

This study measures and decomposes green productivity growth of Korean manufacturing industries between 2004 and 2010 using the Malmquist-Luenberger productivity index. We focus on differences in the measures of productivity growth by distinguishing carbon emissions from either end-user industries or the electricity generation industry. Empirical results suggest three main findings. First, the efficiency of total emissions is higher than that of direct emissions except for the shipbuilding industry. Second, green productivity in the manufacturing sector increased during the study period. Finally, green productivity depends on the indirect emissions of each industry. These results indicate that policymakers need to deliberately develop policy tools for mitigating carbon emissions of the manufacturing industrial sectors based on our empirical findings.

This paper measures the technical inefficiency and the shadow price of Korean fossil-fuel generation companies (GENCOs) between 2001 and 2016 at the firm-level. To obtain robust empirical results, this study employs both commonly used deterministic and stochastic estimation methods. The empirical results are as follows: the inefficiency estimates are approximately 0.09 (deterministic) and 0.08 (stochastic); the estimates of CO2 shadow price, in KRW/tCO2, are 82,758 (deterministic) and 49,830 (stochastic), which shows high volatility in the annual average shadow price. In addition, we find that the results of the deterministic method without any random errors show a large variation in the trends of technical inefficiency and shadow price, while the stochastic method with random errors yields only moderate volatility. Our empirical results are expected to assist policymakers in determining how much potential mitigation can be achieved through improved efficiency, and the range of the CO2 shadow price will contribute to more efficient policy tools.

This study measures and decomposes green productivity growth of Korean manufacturing industries between 2004 and 2010 using the Malmquist-Luenberger productivity index. We focus on differences in the measures of productivity growth by distinguishing carbon emissions from either end-user industries or the electricity generation industry. Empirical results suggest three main findings. First, the efficiency of total emissions is higher than that of direct emissions except for the shipbuilding industry. Second, green productivity in the manufacturing sector increased during the study period. Finally, green productivity depends on the indirect emissions of each industry. These results indicate that policymakers need to deliberately develop policy tools for mitigating carbon emissions of the manufacturing industrial sectors based on our empirical findings.

This dissertation explores the contacts, conflicts, and contestations surrounding Seoul's city walls, and how they shaped Seoul's transformation and Korea's transition from the opening of the ports to the early colonial period (1876-1919). One of the main goals in this dissertation is to assert the inseparable connection between the capital and its city walls in the premodern period, and thereby the importance of examining various contestations and negotiations over its city walls in understanding Seoul's transformation into a modern city. More specifically, not only was the construction of Seoul's city walls instrumental in establishing Seoul as a capital and Chosoˇn as a dynasty, but also its very existence came to symbolize royal authority and national sovereignty within the changing sociopolitical conditions of the Chosoˇn dynasty as well as the diplomatic relationships in the larger East Asian contexts. In the same way, I argue that, the reverse, the destruction of the walls--both as symbolic and physical boundaries--played a significant role in Seoul's transformation and Korea's transition from the premodern to modern period in the global context. By largely focusing on forces from above and their intentions, the existing scholarship presents Seoul's transformation during this period as a progression from the royal capital Hansoˇng (1394-1897) to the imperial capital Hwangsoˇng (1897-1910), before being disrupted by Japanese rule as the colonial city Kyoˇngsoˇng (1910-1945). Stepping outside this teleological explanation, my dissertation challenges and adds complexities to the existing narratives by revealing how the Taehan Empire's efforts to make Seoul as a spatial manifestation of its imperial power were contested by other historical groups' attempts to respatialize the capital with different agendas: to an extraterritorial space, a democratic space, and a colonial space. Within a larger theoretical framework of the mutually constitutive relationship between space and society, this study argues that the transformation of Seoul from a walled to an open space was a process in which various historical actors competed against and cooperated with one another to make Seoul a new space of possibilities, at the crossroads of modernity in Korea.

To evaluate the changes of the corneal epithelial thickness (ET) profile induced by combined small incision lenticule extraction and accelerated corneal collagen crosslinking (SMILE-xtra) for myopia compared with the standard small incision lenticule extraction (SMILE). Nuri Eye Hospital, 61, Dunsan-ro, Seo-gu, Daejeon, 35233, Korea. Retrospective cross-sectional study. Thirty-one myopic eye undergoing SMILE-xtra and control group of 36 myopic eyes undergoing SMILE were retrospectively analyzed. Spectral-domain optical coherence tomography (CIRRUS[TM] HD-OCT 5000, ZEISS, Dublin, CA) was used to measure corneal ET of 17 zones within the central 7-mm zone at preoperative, postoperative 1 month, 3 months and 6 months. Postoperative ET alterations were analyzed for correlation with treatment parameters. There was no difference in preoperative mean age, postoperative MRSE, visual acuity, and ablation depth between the two groups, and there was a significant difference in preoperative central corneal thickness. Both groups showed the greatest increase in corneal ET in the paracentral area on the inferotemporal area, respectively, for 6 months. The preoperative MRSE and the ablation depth showed significant correlation with the postoperative epithelial thickening in mid-peripheral sectors in both groups, and significant negative correlations in paracentral sectors only in SMILE-xtra group. It is significant as the first study to compare corneal epithelial remodeling between SMILE and SMILE with accelerated corneal collagen crosslinking. The SMILE-xtra with the relatively large corneal ablation did not show a significant difference in the pattern of corneal epithelial remodeling compared to the SMILE group.

Background Tumor-associated macrophages (TAMs) are the major component of tumor-infiltrating immune cells. Macrophages are broadly categorized as M1 or M2 types, and TAMs have been shown to express an M2-like phenotype. TAMs promote tumor progression and contribute to resistance to chemotherapies. Therefore, M2-like TAMs are potential targets for the cancer immunotherapy. In this study, we targeted M2-like TAMs using a hybrid peptide, MEL-dKLA, composed of melittin (MEL), which binds preferentially to M2-like TAMs, and the pro-apoptotic peptide d (KLAKLAK) 2 (dKLA), which induces mitochondrial death after cell membrane penetration. Methods The M1 or M2-differentiated RAW264.7 cells were used for mitochondrial colocalization and apoptosis test in vitro. For in vivo study, the murine Lewis lung carcinoma cells were inoculated subcutaneously in the right flank of mouse. The dKLA, MEL and MEL-dKLA peptides were intraperitoneally injected at 175 nmol/kg every 3 days. Flow cytometry analysis of tumor-associated macrophages and immunofluorescence staining were performed to investigate the immunotherapeutic effects of MEL-dKLA. Results We showed that MEL-dKLA induced selective cell death of M2 macrophages in vitro, whereas MEL did not disrupt the mitochondrial membrane. We also showed that MEL-dKLA selectively targeted M2-like TAMs without affecting other leukocytes, such as T cells and dendritic cells, in vivo. These features resulted in lower tumor growth rates, tumor weights, and angiogenesis in vivo. Importantly, although both MEL and MEL-dKLA reduced numbers of CD206 + M2-like TAMs in tumors, only MEL-dKLA induced apoptosis in CD206 + M2-like TAMs, and MEL did not induce cell death. Conclusion Taken together, our study demonstrated that MEL-dKLA could be used to target M2-like TAMs as a promising cancer therapeutic agent.

To evaluate the changes of the corneal epithelial thickness (ET) profile induced by combined small incision lenticule extraction and accelerated corneal collagen crosslinking (SMILE-xtra) for myopia compared with the standard small incision lenticule extraction (SMILE). Nuri Eye Hospital, 61, Dunsan-ro, Seo-gu, Daejeon, 35233, Korea. Retrospective cross-sectional study. Thirty-one myopic eye undergoing SMILE-xtra and control group of 36 myopic eyes undergoing SMILE were retrospectively analyzed. Spectral-domain optical coherence tomography (CIRRUS™ HD-OCT 5000, ZEISS, Dublin, CA) was used to measure corneal ET of 17 zones within the central 7-mm zone at preoperative, postoperative 1 month, 3 months and 6 months. Postoperative ET alterations were analyzed for correlation with treatment parameters. There was no difference in preoperative mean age, postoperative MRSE, visual acuity, and ablation depth between the two groups, and there was a significant difference in preoperative central corneal thickness. Both groups showed the greatest increase in corneal ET in the paracentral area on the inferotemporal area, respectively, for 6 months. The preoperative MRSE and the ablation depth showed significant correlation with the postoperative epithelial thickening in mid-peripheral sectors in both groups, and significant negative correlations in paracentral sectors only in SMILE-xtra group. It is significant as the first study to compare corneal epithelial remodeling between SMILE and SMILE with accelerated corneal collagen crosslinking. The SMILE-xtra with the relatively large corneal ablation did not show a significant difference in the pattern of corneal epithelial remodeling compared to the SMILE group.