Earticle

한국의 ROTC 제도는 유능한 초급장교 충원과 평시부터 예비전력 확보를 위해 1961년에 미국으로부터 도입되었다. 하지만 2000년대 접어들어 저출산에 따른 학령인구 및 병역자원의 감소, 병 복무기간까지 단축되는 획득환경의 변화로 지원율이 점점 하락하는 심각한 위기에 직면하게 되었다. 따라서 본 연구는 이러한 획득환경의 변화와 그에 따른 지원 율 감소의 원인을 분석하여 조직편성 및 운영체계를 중심으로 ROTC 제도 개선방안을 제시하고자 하였다. 연구방법은 국내 외 문헌연구를 통해 미국과 한국의 ROTC 제도에 관한 사례 간 비교기법을 적용하였다. 이론적 측면에서는 지식 기반사회에서 조직의 성과달성과 비교경쟁우위 확보를 위해 기업경영에 적용하고 있는 전략적 인적자원관리를 이론적 준거로 삼았다.

Korea's ROTC system was introduced from the United States in 1961 to recruit competent primary grade officers and secure reserve forces in peacetime. However, entering the 2000s, it was faced with a serious crisis, which was a decrease of the application rate due to the change in the acquisition environment including the decrease in school-age population and military service resources due to the low fertility, and the shortened period of military service. Therefore, this study tried to suggest a ROTC system improvement plan focusing on the organizational structure and operation system by analyzing the change in the acquisition environment and the cause of decrease in the application rate. As a research method, a comparative method between the cases of the ROTC systems in the US and Korea was applied through domestic and foreign literature studies. In terms of theory, Strategic Human Resource Management, which is applied to corporate management to achieve organizational performance and secure comparative competitive advantage in a knowledge-based society, was used as a theoretical criterion.

Massive multiple-input multiple-output (MIMO) systems have become an essential feature in the fifth-generation (5G) wireless communication networks. Due to the commercialization of 5G mobile communication devices, the number of multi-antenna devices have increased over the years. Therefore, a precoding scheme based on multi-antenna users is an inevitable feature that needs to be analyzed in massive MIMO systems. The asymptotic ergodic sum-rate analysis of block diagonalization (BD) based multiuser MIMO systems is performed in this study. Based on the random matrix theory results derived from the massive base station antenna characteristics, the singular values of the block diagonalized channel are obtained asymptotically, and thereby, the closed-form expression for the BD based sum-rate is derived. The asymptotic sum-rate performance gap between the BD and the zero-forcing beamforming is then analyzed. Moreover, from the derived asymptotic sum-rate, the optimal number of users needed to maximize the ergodic sum-rate is proposed. Simulation results show that the derived asymptotic analyses are closely aligned to the sum-rate obtained by Monte Carlo simulations. In addition, the simulation results prove that the maximum ergodic sum-rate can be achieved by using the proposed number of users.

장기불황으로 인해 한국 청년실업률이 수년간 10% 안팎의 높은 수준을 유지하고 있는 가운데, 주요 경제활동 인구인 30~40대의 실업률이 최근 상승세를 보이고 있다. 정부의 기존 청년 중심의 고용촉진 및 실업복지 정책을 30~40대를 포함한 다양한 연령층으로 확대·강화하기 위해서는 각 연령층에 대한 실업예측 모형 연구가 필요하다. 이 에 본 연구에서는 한국 통계청 실업률 자료와 구글 검색어를 활용하여 한국 30~40대 연령층에 특화된 실업률 예측모 형을 개발하고자 하였다. 실업률 자료와 계절성 자기회귀누적이동평균 모형을 활용하여 기초모형(Model 1)을 다중선 형회귀 모형으로 추정하였으며, 개선된 모형을 구하고자 구글 검색 질의어 정보를 Model 1에 추가 활용하였다(Model 2). 그 결과, 30대와 40대 연령층 모두 구글 검색 질의어를 추가 활용한 Model 2가 Model 1보다 우수한 예측력을 보였다. 이는 웹 검색 질의어가 여전히 한국의 실업률 예측모형을 개선하는 데 유의미함을 의미한다. 본 연구는 실질적 인 활용을 위해 추가적인 연구가 필요하지만, 연령대별 실업률 예측 연구에 기여할 것으로 판단된다.

Prolonged recession has caused the youth unemployment rate in Korea to remain at a high level of approximately 10% for years. Recently, the number of unemployed Koreans in their 30s and 40s has shown an upward trend. To expand the government’s employment promotion and unemployment benefits from youth-centered policies to diverse age groups, including people in their 30s and 40s, prediction models for different age groups are required. Thus, we aimed to develop unemployment prediction models for specific age groups (30s and 40s) using available unemployment rates provided by Statistics Korea and Google search queries related to them. We first estimated multiple linear regressions (Model 1) using seasonal autoregressive integrated moving average approach with relevant unemployment rates. Then, we introduced Google search queries to obtain improved models (Model 2). For both groups, consequently, Model 2 additionally using web queries outperformed Model 1 during training and predictive periods. This result indicates that a web search query is still significant to improve the unemployment predictive models for Koreans. For practical application, this study needs to be furthered but will contribute to obtaining age-wise unemployment predictions.

PURPOSES : Emulsified asphalt is critical for road construction. The objective of applying asphalt emulsion as an adhesive is to prevent the phenomenon of debonding between the upper and lower layers. The quantity and veriety of bituminous material can be varied according to the type of pavement and site conditions. The objective of this study is to reveal the optimum application rates of the emulsified asphalt materials by types of tack-coats using Interface Shear Strength(ISS). METHODS : In the research, emulsified asphalt was paved on the surface of the divided mixture. The specimens of paving asphalt emulsion were utilized to evaluate the bond strength of tack-coat materials. In the evaluation process, NCHRP Report 712 was utilized to investigate the Interface Shear Strength, which reflects the bond capacity of asphalt emulsion. Then, the optimum residual application rates by tack-coat types were determined using regression analysis. RESULTS :As a consequence of squared R values investigated from 0.7 to 1 as part of the regression analysis, the tendency of predicted ISS values was compared with the results. The optimum residual application rates of AP-3, RS(C)-4, QRS-4, and BD-Coat were determined to be $0.78{\ell}/m^2$, $0.51{\ell}/m^2$, $0.53{\ell}/m^2$, and $0.73{\ell}/m^2$, respectively, utilizing 4th regression analysis. CONCLUSIONS :Based on the result of this study, it was not feasible to conclude whether higher residual application of tack-coat material leads to improved bond capacity. Rather, the shearing strength varies depending on the type of pavement.

To determine the optimum N rate in Jeju island for utricle and root production of Achyranthes japonica Nakai, a medicinal plant, the plants were grown at two plant densities (50 and 100 hills/㎡, two plants per hill; main plots) at six N application rates (0, 6, 12, 18, 24, and 30 ㎏/10a; split plots) in 2001. there was no significant interaction between plant density and N application rate for all measured agronomic characters. Main root length and roots per hill were 5 and 52% grater, respectively, but N content of stover was lower under lower plant density compared to higher plant density. The other characters were not affected by plant density. N application rate did not significantly affect main stem diameter, spikes per hill, spike length, utricles per spike, main root length and diameter, and utricle N content. As N rate increased from 0 to 30 ㎏/10a, SPAD values and stover N content increased linearly from 35.0 to 40.5 and 1.09 to 1.38%, respectively, and plant hight, branches per hill, stover, utricle and root dry matter yields, roots per hill, and top N yield increased quadratically. Spikes per hill were increased in a cubic manner with increased N application rates. N application rate for the maximum dry matter yield of utricle and root in A. japonica was estimated to be 21 ㎏ N/10a.

u-Transportation (u-T) 환경은 차세대의 ITS로 간주되는 미래형 교통서비스로서 어디에서나 적절한 교통서비스를 제공하는 신 교통공간을 의미한다. 그러한 환경의 기초연구로서 본 연구는 기존 ITS에서 교통량 산출 방법을 검토하고, u-T 자료 수집환경(u-TSN)의 자료수집형태를 시뮬레이션으로 구현하여 ITS의 교통량 산정 결과와의 차이점을 연구하였다. 그 결과, u-T에서 단속류의 교통류율이 ITS보다 3.58% 높게 나타났으며, 평가지표 MARE와 MAE 값이 각각 31.4%, 31.1% 낮게 나타나고, 평가지표 균등계수는 1.9% 높게 나타나 상대적으로 u-TSN의 교통자료 집계가 더 우수함을 알 수 있었다. 이는 상류부 링크의 특정지점 교통량을 고려하지 못한 기존 방법론에 비해, u-T에서의 링크 특성이 잘 반영된 링크의 대표치라는데 의의 또한 있는바, 설계시간계수 등의 설계분야, 운영 분야 등에 보다 적절한 교통류율의 제공이 가능할 것으로 판단된다.

u-T (ubiquitous transportation) environment can be envisioned as an advanced version of ITS environment and be expected to provide more advanced transportation service in a ubiquitous manner. As a basic necessity to measure traffic flow in both environments, a flow estimation method was proposed. Flows have been measured in existing ITS and in a new u-T environments and some differences were investigated using simulation technique. In the interrupted traffic situation, the flow rate of u-T is 3.58% higher than that in ITS environment. Both MARE and MAE, which were used as measure of effectiveness, in u-T were better since the results are 31.4% and 31.1% lower than in ITS, respectively. Besides the equality coefficient in u-T was 1.9% higher than that in ITS. Such being the case, the flow rate measured in u-T using U-TSN is more reliable and can be expected to be successfully used for transportation system design or traffic operation areas.

구조물의 파괴 거동은 하중의 재하 속도에 따라 달라지는 특성을 보이는데, 이는 재료의 속도 의존성으로부터 비롯된다고 할 수 있다. 이러한 현상은 공학의 여러 분야에서 관심사였지만, 파괴 메커니즘이 명확히 규명되지 않았기 때문에 수치 해석을 통한 연구에는 그 한계점과 어려움이 상존하였다. 본 연구에서는 파괴 거동의 속도 의존성을 이해하고자, 취성재료를 대상으로 입자동역학을 이용한 수치해석을 수행하였다. 직접 인장 시험 시뮬레이션을 위해 노치가 있는 시편을 모델링하고, 취성재료가 갖는 특성을 표현하기 위해 Lennard-Jones 포텐셜을 사용하였다. 6가지의 다른 하중 속도에 따른 균열의 거칠기, 균열의 후퇴와 멈춤, 분기 현상과 같은 동적 파괴 특성을 관찰하였다. 해석 결과를 통해 하중 속도에 따른 파괴 거동의 변화 원인을 에너지 유입-소모율의 개념을 도입하여 설명하고, 재료의 파괴 메커니즘이 갖는 속도 의존성에 대해 이해할 수 있는 단초를 마련하였다. 또한, 기존 실험과의 비교를 통해 실제적인 현상과의 유사성을 밝힘으로써 입자동역학의 공학적 적용 가능성을 제시하였다.

The failure behavior of structures is changed under different loading rates, which might arise from the rate dependency of materials. This phenomenon has been focused in the engineering fields. However, the failure mechanism is not fully understood yet, so that it is hard to be implemented in numerical simulations. In this study, the numerical experiments to a brittle material are simulated by the Molecular Dynamics (MD) for understanding the rate dependent failure behavior. The material specimen with a notch is modeled for the compact tension test simulation. Lennard-Jones potential is used to describe the properties of a brittle material. Several dynamic failure features under 6 different loading rates are achieved from the numerical experiments, where remarkable characteristics such as crack roughness, crack recession/arrest, and crack branching are observed during the crack propagation. These observations are interpreted by the energy inflow-consumption rates. This study will provides insight about the dynamic failure mechanism under different loading rates. In addition, the applicability of the MD to the macroscopic mechanics is estimated by simulating the previous experimental research.

본 연구에서는 이전에 저자가 제안한 감가상각누적비율함수를 이용한 감가상각방법의 실질적인 활용을 위한 보다 상세한 설명을 제시한다. 감가상각누적비율함수는 상각대상금액에 대한 임의의 시점까지의 상각누적비율 값을 제공해 주는 함수로, 시간의 경과에 기반을 둔 감가상각방법에 활용될 수 있다. 이 함수를 사용하면 매 회기의 상각액이 일정하거나, 점차 감소하거나, 점차 증가하는 모든 경우의 상각금액을 체계적으로 계산해낼 수 있어, 각 자산의 특성에 맞는 다양한 감각상각형태를 합리적으로 선택하여 사용할 수 있다. 또한, 상각누적비율이 시간의 연속함수로 표현됨으로써 기중에 자산을 취득하거나 처분하는 경우에도 체계적이고 일관성 있게 감가상각비를 상계할 수 있게 된다. 다만, 함수의 매개변수 값을 얼마로 지정할 것인가 하는 문제가 존재하는데 본 연구에서 그에 대한 자료를 제공한다.

This article presents detailed explanations of the depreciation method using the accumulated depreciation rate function(ADRF) proposed by the author previously, for the practical application. ADRF provides a value of accumulated depreciation rate on the total depreciation charge at any given time, therefore it can be used in a time-based depreciation method. Since the depreciation charge of each period can be systematically computed with ADRF, in every case where the charge is constant or decreasing or increasing, we can choose diverse rational depreciation types for the characteristic of every asset. Also, since the ADRF is the continuous function of time, we can compute the depreciation charge with consistency in cases where assets are owned for partial period. However, we should determine the value of parameter of ADRF. We give some data on the problem.

최근 모바일 기기와 무선기술을 활용한 의료지원과 공중보건사업을 일컫는 mobile health (mHealth) 중 애플리케이션이 신체 및 정신건강 영역에 적극적으로 활용되고 있으나, 그 효과성에 대한 근거는 매우 부족하다. 본 연구에서는 걷기 및 신체활동 증진을 목적으로 하는 mHealth 애플리케이션에 적용할 수 있는 효과적이고 효율적인 강화계획을 탐색하고자 하였다. 이를 위해 강화물의 초기값과 증가율을 조작한 세 가지 증가강화계획 프로그램(큰 초기값-10% 증가율, 중간 초기값-25% 증가율, 작은 초기값-100% 증가율)을 설계하고, 이의 상대적 효과성과 비용 효율성을 검증하기 위해 대학생 66명(남 16명, 여 50명)을 세 가지 프로그램에 무선할당하여 66일간 개입을 실시하였다. 연구 결과, 개입의 효과성 측면에서, 중간 초기값-25% 증가율 집단에서 큰 초기값-10% 증가율 집단에 비해 걸음 수 증가량이 유의하게 컸고, 작은 초기값-100% 증가율 집단에 비해 총 신체활동 증가량이 유의하게 컸다. 다음으로 개입의 비용 효율성의 측면에서, 중간 초기값-25% 증가율 집단과 작은 초기값-100% 증가율 집단에서 큰 초기값-10% 증가율 집단에 비해 사용된 강화물 대비 걸음 수 증가량이 유의하게 컸다. 마지막으로, 개입 종료 66일 후의 추적 조사에서 집단에 관계없이 개입 기간 증가한 걸음 수는 유지되었으나, 자기보고를 통해 증가한 것으로 나타난 총 신체활동량 및 걷기 활동량은 유지되지 않았다. 이러한 결과를 바탕으로 본 연구의 임상적 함의와 한계점에 대해서 논의하였다.

While mobile applications, a type of mobile health (mHealth), have been widely used for achieving physical and mental health objectives, evidence on the effectiveness of mobile applications is limited. This study aimed to examine the effectiveness, cost-effectiveness, and durability of three reinforcement systems that are applicable to mHealth applications. For this purpose, a total of 66 college students (16 males and 50 females) were randomly assigned to the following three groups: the big initial magnitude-10% escalating rate group (Group 1), the moderate initial magnitude-25% escalating rate group (Group 2), and the small initial magnitude-100% escalating rate (Group 3). After 66 days of intervention, the results showed that participants in Group 2 had significantly increased walking behavior compared to participants in Group 1 and significantly increased total physical activity compared to participants in Group 3. In terms of cost-effectiveness, participants in Group 2 and Group 3 showed significantly increased walking behavior per provided reinforcer amount compared to participants in Group 1. In addition, durability of the effects on walking behavior in all groups was found at 66 days after the intervention, but durability of the effects on self-reported total physical activity and walking was not found. Implications and limitations are further discussed.

본 연구의 목적은 수도권과 비수도권 경력단절 여성의 재취업률 차이의 결정요인을 실증적으로 분석하여 여성의 노동시장 참여 증진에 필요한 정책 대안을 모색하는 데 있다. 본 연구에 사용된 자료는 통계청에서 제공하는 인구주택총조사 2015년 자료이며 연구대상은 만 25-64세의 결혼 전 취업 경험이 있는 여성으로 한정하였다. 본 연구에 활용된 방법론은 다변량 해체기법으로 수도권과 비수도권 간 경력단절 여성의 재취업 확률 차이를 특성효과와 잔차효과로 분리하여 분석하였다. 분석 결과, 경력단절 여성의 재취업 확률은 비수도권이 수도권보다 높은 것으로 나타났다. 지역 간 경력단절 여성의 재취업 확률 차이엣는 잔차효과가 94%로 해당 분석을 설명하는 주요 효과임이 드러났으며, 해당 효과를 설명하는 주요 변인은 자녀 수, 교육수준, 자가거주 여부인 것으로 나타났다. 분석 결과를 정리해보면, 두 지역 간 경력단절 여성의 재취업 확률 차이를 발생시킨 근본적 요인은 지역 간 경제력 격차로 인한 여성의 재취업에 대한 동기부여 차이와 고용불일치 문제인 것으로 파악된다. 본 연구의 의의는 지역 간 경력단절 여성의 재취업 확률 차이를 다변량 해체기법을 통해 결정요인을 분석했다는 점과 지역 간 재취업 확률 차이를 해소하기 위한 정책 방향을 제시했다는 데 있다.

The purpose of this study is to statistically find determinants which make differences of career-broken women’s reemployment rate between capital and non-capital region. This study used Korea census of Population and Housing 2015 data and utilized a sample of women aged between 25 and 64 with premarital employment experience. By applying multivariate decomposition method, this study analyzed regional differences in career-broken women’s reemployment rate with endowment and residual effect. The study found that career-broken women in the non-capital region showed higher rate of being reemployed than those in the capital region. Main factors that made differences were number of kids, high school graduate, and own house variables for residual effect. In sum up, this study found that motivation of reemployment caused by regional gap in economic power and regional employment mismatch affects on the differences in career-broken women’s reemployment rate between the capital and non-capital regions. This study concludes with suggesting the policy direction to lessen the regional gap in career-broken women’s reemployment.

The necessity of the certification system for individual buildings, both at home and abroad, is spreading throughout the building industry, and the certification standards of each country are also becoming effective systems through trial and error. On the other hand, complex development, neighborhood design, further urban design and urban development stages have greater impact on the urban environment than individual buildings, and the necessity of an green building certification system is continuously raised. This study examines the LEED for Neighborhood Development (LEED-ND) certification standards for neighborhood development projects, established and operated by the Green Building Council in the United States. By analyzing the detailed criteria of the items with high application rate, we derived the key elements that represent the ultimate purpose and direction of LEED-ND. Based on this, it is intended to provide the basic data necessary for the improvement and supplementation of the concept of green neighborhood in Korea to be extended to the urban environment level beyond the individual building-oriented standards.

The purpose of this study is to statistically find determinants which make differences of career-broken women’s reemployment rate between capital and non-capital region. This study used Korea census of Population and Housing 2015 data and utilized a sample of women aged between 25 and 64 with premarital employment experience. By applying multivariate decomposition method, this study analyzed regional differences in career-broken women’s reemployment rate with endowment and residual effect. The study found that career-broken women in the non-capital region showed higher rate of being reemployed than those in the capital region. Main factors that made differences were number of kids, high school graduate, and own house variables for residual effect. In sum up, this study found that motivation of reemployment caused by regional gap in economic power and regional employment mismatch affects on the differences in career-broken women’s reemployment rate between the capital and non-capital regions. This study concludes with suggesting the policy direction to lessen the regional gap in career-broken women’s reemployment.