2023, Vol.6, No.2

Journal of Advances in Military Studies 2025 KCI Impact Factor : 1.0

pISSN : 2635-5531 / eISSN : 2636-1329
https://journal.kci.go.kr/jams

We conducted simulations to analyze the effects of a hard-kill-type underwater defense system that defends friendly warships against an enemy wake-homing torpedo. Assuming that the enemy torpedo is a wake-homing torpedo, our surface warship detours to the prespecified evasive course by firing a hard-kill-type system, which is modeled as a passive acoustic homing-torpedo, to attack the enemy torpedo. We analyzed the effectiveness of a warship’s survival probability via Monte Carlo simulation, given the probabilistic angles of the launched torpedoes, to compare two cases where one used only evasive maneuvering and the other used the hard-kill-type underwater defense system with evasion at the same time. By changing the maximum torpedo detection range of a warship and the torpedo’s initial location, we observed that the resulting survival probability of a warship was above 61% with a hard-kill-type defense system, whereas it remained at 34% without a hard-kill defense system, the necessity of a hard-kill underwater defense system, especially against wake-homing torpedoes.

The rapid advancement in software-based technology has significantly shortened product life cycles, leading to the proliferation of new products. However, the high initial investment makes it practically impossible for armed forces to rapidly replace existing weapons systems with new ones due to technological obsolescence. A more realistic alternative is to focus on performance improvements (or weapon upgrades) in existing systems. The challenge lies in making the right upgrades with the right technology at the right cost and time given the limited defense budget. Unfortunately, weapons upgrade decisions have mostly been based on costs and politically considered budget allocations to different branches of the armed forces rather than by considering a comprehensive range of decision factors. In light of the escalating national security threats, it is necessary to maximize the cost-effectiveness of weapons upgrade projects and effectively address rising national security challenges. The objective of this study is to develop a performance improvement Decision Index that quantifies the opinions of field-operating experts. Field experts are believed to possess the necessary expertise to select the appropriate fighter types, technologies, and upgrade timings, making it beneficial to factor in their opinions to determine what, how, and when to upgrade. Specifically, this study aims to establish weighted values for major decision factors regarding fighter performance improvement programs in the Republic of Korea Air Force. To achieve this, we collected survey data from 134 active-duty pilots and maintenance, operations, and repair (MRO) personnel from major fighter wings of the Republic of Korea Air Force and analyzed the data using the Fuzzy-AHP (Analytical Hierarchy Process). The analysis results indicate that the highest weighted value is given to the “relative (fighter) performance”against hostile nations, followed by “operating rate,” “durability,” “performance improvement cycle,” and “budget.” Furthermore, this study identified perceptual differences among field experts—particularly between pilots and MRO personnel—regarding the importance of relative performance, budget, performance improvement intervals, and operating rates of different fighter types. The proposed performance improvement index aims to provide a quantitative tool that incorporates field experts’ opinions into the decision-making process to upgrade weapons, facilitating balanced decisions and departing from a policymaker-centered approach. This balanced approach to weapons upgrade decisions will contribute to maximizing cost-effectiveness and, eventually, enhancing combat readiness.

This study focuses on the size of reserve forces and the factors affecting their size. As a result of analyzing theory and prior research, we identified the relations between standing and reserve forces. To minimize the problem of relations, we used a two-stage least squares estimate with simultaneous equations as the analytical method used. We utilized the 2022 cross-sectional data points and analyzed the sample by dividing it into 69 countries and 38 countries with reserve forces. In 38 countries, the reserve force size derived from regression analysis was 2.2 million people, and the standing force size was 470,000 people. The empirical analysis shows that 2.2 million reserve forces solved the single-equation estimation problem caused by the two-way causal relationship between reserve force size and standing force size through simultaneous equations, which further improved the consistency of the estimated coefficients. In terms of size, it was smaller than the 2.75 million presented in Defense Reform 2.0, which seems to be due to the analysis of countries with relatively capital-intensive military structures compared with Korea. Various factors are expected to further increase the size of future reserve forces: the rapid decline in the nation’s birth population; the proportion of defense spending to the government’s budget; the reserve forces, which have been further expanded by Defense Reform 2.0; and the prospect of a reduction in standing forces expected by Defense Innovation 4.0. Therefore, the size of future appropriate reserve forces will increase further than the current appropriate level, making it necessary to determine policies related to reserve forces and develop appropriate measures for procurement.